[Jenn]

....of listening to music through home audio equipment. In about 35
years, for all of the gear I've had, from Sears on up, I've had a power
switch on a SAE amp go out after 3 years of use in 1983. That's it. Am
I lucky, or do you have similar experiences?

[Trevor Wilson[_2_]]

"MiNe 109" wrote in message
...
In article

et,
Jenn wrote:

...of listening to music through home audio equipment. In about 35
years, for all of the gear I've had, from Sears on up, I've had a power
switch on a SAE amp go out after 3 years of use in 1983. That's it. Am
I lucky, or do you have similar experiences?

I was surprised to learn that my Linn electronic crossover required more
than one hundred fifty replacement capacitors. Then I found my Linn amp
needed a similar action when I plugged in the newly repaired crossover.

The capacitors on my LP12 power supply died a couple of years back. I
wonder if these Linn capacitor failures are a coincidence.


**Read the specs on capacitors sometime. It's quite scarey. Electrolytic
caps are usually rated to XXXX hrs @ 85oC or 105oC. The better the cap, the
more hours and the higher the temp. Naturally, the cap is derated, as the
temperature rises. A typical cap found in a domestic product would be rated
for around 5,000 hours @ 85oC. A mil-spec cap might be typically 20,000
hours @ 105oC. The difference in cost would be substantial. Keep your caps
cool. Fan cooling is best.

Trevor Wilson

[[email protected]]

You are lucky.

Jenn wrote:
: ...of listening to music through home audio equipment. In about 35
: years, for all of the gear I've had, from Sears on up, I've had a power
: switch on a SAE amp go out after 3 years of use in 1983. That's it. Am
: I lucky, or do you have similar experiences?

[Trevor Wilson[_2_]]

"MiNe 109" wrote in message
...
In article ,
"Trevor Wilson" wrote:

"MiNe 109" wrote in message
...
In article

et,
Jenn wrote:

...of listening to music through home audio equipment. In about 35
years, for all of the gear I've had, from Sears on up, I've had a
power
switch on a SAE amp go out after 3 years of use in 1983. That's it.
Am
I lucky, or do you have similar experiences?

I was surprised to learn that my Linn electronic crossover required
more
than one hundred fifty replacement capacitors. Then I found my Linn amp
needed a similar action when I plugged in the newly repaired crossover.

The capacitors on my LP12 power supply died a couple of years back. I
wonder if these Linn capacitor failures are a coincidence.


**Read the specs on capacitors sometime. It's quite scarey. Electrolytic
caps are usually rated to XXXX hrs @ 85oC or 105oC. The better the cap,
the
more hours and the higher the temp. Naturally, the cap is derated, as the
temperature rises. A typical cap found in a domestic product would be
rated
for around 5,000 hours @ 85oC. A mil-spec cap might be typically 20,000
hours @ 105oC. The difference in cost would be substantial. Keep your
caps
cool. Fan cooling is best.

My repairman used mil-spec replacements for about the same price Linn
would have charged to renew the original parts.

**That'd be about right.


I think I'll go turn off some amps now.

**Good idea. And next time some idiot tells you to keep your amp switched
on, send them the repair bill.

Trevor Wilson

[George M. Middius]

MiNe 109 said:

My repairman used mil-spec replacements for about the same price Linn
would have charged to renew the original parts.

Been there done, that.

I think I'll go turn off some amps now.

Careful of the puddles!

[Arny Krueger]

"Jenn" wrote in message
...

...of listening to music through home audio equipment. In about 35
years, for all of the gear I've had, from Sears on up, I've had a power
switch on a SAE amp go out after 3 years of use in 1983. That's it. Am
I lucky, or do you have similar experiences?

It all depends on how long you are keeping the piece of equipment in
service. For example, if you're still using that SAE amp as your daily
driver, and you know for sure that it still meets spec, then your story is
interesting. If you change power amps every 30 days, then it isn't. ;-)

[Arny Krueger]

"MiNe 109" wrote in message
...
In article ,
"Trevor Wilson" wrote:

"MiNe 109" wrote in message
...
In article

et,
Jenn wrote:

...of listening to music through home audio equipment. In about 35
years, for all of the gear I've had, from Sears on up, I've had a
power
switch on a SAE amp go out after 3 years of use in 1983. That's it.
Am
I lucky, or do you have similar experiences?

I was surprised to learn that my Linn electronic crossover required
more
than one hundred fifty replacement capacitors. Then I found my Linn amp
needed a similar action when I plugged in the newly repaired crossover.

The capacitors on my LP12 power supply died a couple of years back. I
wonder if these Linn capacitor failures are a coincidence.


**Read the specs on capacitors sometime. It's quite scarey. Electrolytic
caps are usually rated to XXXX hrs @ 85oC or 105oC. The better the cap,
the
more hours and the higher the temp. Naturally, the cap is derated, as the
temperature rises. A typical cap found in a domestic product would be
rated
for around 5,000 hours @ 85oC. A mil-spec cap might be typically 20,000
hours @ 105oC. The difference in cost would be substantial. Keep your
caps
cool. Fan cooling is best.

My repairman used mil-spec replacements for about the same price Linn
would have charged to renew the original parts.

He was probably marking those mil-spec parts up fantastically. In small
volumes, the actual additional cost of a more competent part obtained
competently is usually only marginal.

[Arny Krueger]

"MiNe 109" wrote in message
...

My repairman used mil-spec replacements for about the same price Linn
would have charged to renew the original parts.

He was probably marking those mil-spec parts up fantastically. In small
volumes, the actual additional cost of a more competent part obtained
competently is usually only marginal.

For the crossover, he installed 150 caps for $250 and was finished the
next day.

Very unlikely. There aren't 150 capactors in 10 speakers, let alone 1.

Interesting that 'same price for better specs' translates to 'fantastic
markup' for you.

Stephen, can't read can you? Or is it that context means nothing to you?
The above is irrelevant to what I said, and more strikingly, it is
irrelevant to what you said.

You can buy motor oil cheaper in the store than at the mechanic's, too.

Of course, but irrelevant.

[Arny Krueger]

"MiNe 109" wrote in message
...
In article ,
"Arny Krueger" wrote:

"MiNe 109" wrote in message
...

My repairman used mil-spec replacements for about the same price
Linn
would have charged to renew the original parts.

He was probably marking those mil-spec parts up fantastically. In
small
volumes, the actual additional cost of a more competent part obtained
competently is usually only marginal.

For the crossover, he installed 150 caps for $250 and was finished the
next day.

Very unlikely. There aren't 150 capactors in 10 speakers, let alone 1.

It's a three-way active crossover on a circuit board. I got a plastic
bag full of dead parts in exchange. There were also repairs to the power
supply, so it's possible the total was of assorted parts.

Maybe 15 parts.

An online forum post describes a similar Linn crossover: "Linn
definitely claim some correction for phase in the Isobarik Aktiv box, it
has a lot of electronics in it. Including two rows of 8 stages of
something with a capactitor and two transistors" which were said "The
two neat rows of trannies are basically cascaded all pass phase shift
networks to give you time alignment between the hf & mf sections at
crossover point." The Kabers are three-way, so include more parts than
that.

There's only one way to describe a circuit board that small with 15 bad
parts on it: junk as built.

Interesting that 'same price for better specs' translates to 'fantastic
markup' for you.

Stephen, can't read can you? Or is it that context means nothing to you?
The above is irrelevant to what I said, and more strikingly, it is
irrelevant to what you said.

It's a paraphrase of what you said in reply to what I said. I agree that
it didn't make sense in context.

You can buy motor oil cheaper in the store than at the mechanic's, too.

Of course, but irrelevant.

Exactly relevant to the cost of replacement parts "obtained competently"
by the tech vs the cost to the consumer installed as a repair.

That wasn't what I was talking about. I was talking about the incremental
cost of a higher-spec part which is what you started out talking about.

[Trevor Wilson[_2_]]

"Arny Krueger" wrote in message
. ..

"MiNe 109" wrote in message
...
In article ,
"Trevor Wilson" wrote:

"MiNe 109" wrote in message
...
In article

et,
Jenn wrote:

...of listening to music through home audio equipment. In about 35
years, for all of the gear I've had, from Sears on up, I've had a
power
switch on a SAE amp go out after 3 years of use in 1983. That's it.
Am
I lucky, or do you have similar experiences?

I was surprised to learn that my Linn electronic crossover required
more
than one hundred fifty replacement capacitors. Then I found my Linn
amp
needed a similar action when I plugged in the newly repaired
crossover.

The capacitors on my LP12 power supply died a couple of years back. I
wonder if these Linn capacitor failures are a coincidence.


**Read the specs on capacitors sometime. It's quite scarey. Electrolytic
caps are usually rated to XXXX hrs @ 85oC or 105oC. The better the cap,
the
more hours and the higher the temp. Naturally, the cap is derated, as
the
temperature rises. A typical cap found in a domestic product would be
rated
for around 5,000 hours @ 85oC. A mil-spec cap might be typically 20,000
hours @ 105oC. The difference in cost would be substantial. Keep your
caps
cool. Fan cooling is best.

My repairman used mil-spec replacements for about the same price Linn
would have charged to renew the original parts.

He was probably marking those mil-spec parts up fantastically. In small
volumes, the actual additional cost of a more competent part obtained
competently is usually only marginal.

**Possibly. I just checked my supplier. For a typical decoupling cap (such
as that used in a crossover) the cost of a regular 85oC rated part was
AUS$0.68c each. For a high grade, 105oC part, the cost was $7.19 each. (Same
values) Naturally, there is a range of prices between these values.

Trevor Wilson

[Arny Krueger]

"MiNe 109" wrote in message
...
In article ,
"Arny Krueger" wrote:

"MiNe 109" wrote in message
...
In article ,
"Arny Krueger" wrote:

"MiNe 109" wrote in message
...

My repairman used mil-spec replacements for about the same price
Linn
would have charged to renew the original parts.

He was probably marking those mil-spec parts up fantastically. In
small
volumes, the actual additional cost of a more competent part
obtained
competently is usually only marginal.

For the crossover, he installed 150 caps for $250 and was finished
the
next day.

Very unlikely. There aren't 150 capactors in 10 speakers, let alone
1.

It's a three-way active crossover on a circuit board. I got a plastic
bag full of dead parts in exchange. There were also repairs to the
power
supply, so it's possible the total was of assorted parts.

Maybe 15 parts.

No, even an electronics novice such as myself can tell the difference
between a bag of fifteen parts and a bag of one hundred fifty.

An online forum post describes a similar Linn crossover: "Linn
definitely claim some correction for phase in the Isobarik Aktiv box,
it
has a lot of electronics in it. Including two rows of 8 stages of
something with a capactitor and two transistors" which were said "The
two neat rows of trannies are basically cascaded all pass phase shift
networks to give you time alignment between the hf & mf sections at
crossover point." The Kabers are three-way, so include more parts than
that.

There's only one way to describe a circuit board that small with 15 bad
parts on it: junk as built.

The number fifteen is your guess based on passive crossovers, so we can
move past this claim.

Well Stephen, you usual delusions of mind reading are in evidence as is
usual.

As for 'bad parts,' you must have missed Trevor's posts about the finite
life of electronic components. These may have been as much as twenty
years old, and because of damage to the power switch, run 24/7 for the
last few years.

I don't need Trevor to educate me about the reliability of electronic parts.

The still-excessive failure rate may help explain Linn's continual
redesign of its active crossovers from discrete components to circuit
boards with plug-in modules to plug-in modules placed directly in the
power amp.

Failure of 150 parts in an electronic crossover, even after 20 years of 24/7
use is characteristic of junk-as-built.

Interesting that 'same price for better specs' translates to
'fantastic
markup' for you.

Stephen, can't read can you? Or is it that context means nothing to
you?
The above is irrelevant to what I said, and more strikingly, it is
irrelevant to what you said.

It's a paraphrase of what you said in reply to what I said. I agree
that
it didn't make sense in context.

You can buy motor oil cheaper in the store than at the mechanic's,
too.

Of course, but irrelevant.

Exactly relevant to the cost of replacement parts "obtained
competently"
by the tech vs the cost to the consumer installed as a repair.

That wasn't what I was talking about. I was talking about the incremental
cost of a higher-spec part which is what you started out talking about.

Yes, I said I was able to get the higher-spec'd parts installed for the
supposed cost of a Linn renewal to original specs. Then you said the
repairman got a 'fantastic markup' which doesn't make sense,

It makes as much sense as you care to understand.

As things stand, the whole story is strange.

The number of parts (150 capacitors!) that were replaced was way out of
proportion to reality for either a passive or active crossover. Form
example, there might be 35 capacitors per channel in an active crossover. If
even 25 percent failed after 20 years, it would be a disaster of biblical
proportions!

[Arny Krueger]

"Trevor Wilson" wrote in message
...

"Arny Krueger" wrote in message
. ..

"MiNe 109" wrote in message
...
In article ,
"Trevor Wilson" wrote:

"MiNe 109" wrote in message
...
In article

et,
Jenn wrote:

...of listening to music through home audio equipment. In about 35
years, for all of the gear I've had, from Sears on up, I've had a
power
switch on a SAE amp go out after 3 years of use in 1983. That's it.
Am
I lucky, or do you have similar experiences?

I was surprised to learn that my Linn electronic crossover required
more
than one hundred fifty replacement capacitors. Then I found my Linn
amp
needed a similar action when I plugged in the newly repaired
crossover.

The capacitors on my LP12 power supply died a couple of years back. I
wonder if these Linn capacitor failures are a coincidence.


**Read the specs on capacitors sometime. It's quite scarey.
Electrolytic
caps are usually rated to XXXX hrs @ 85oC or 105oC. The better the cap,
the
more hours and the higher the temp. Naturally, the cap is derated, as
the
temperature rises. A typical cap found in a domestic product would be
rated
for around 5,000 hours @ 85oC. A mil-spec cap might be typically 20,000
hours @ 105oC. The difference in cost would be substantial. Keep your
caps
cool. Fan cooling is best.

My repairman used mil-spec replacements for about the same price Linn
would have charged to renew the original parts.

He was probably marking those mil-spec parts up fantastically. In small
volumes, the actual additional cost of a more competent part obtained
competently is usually only marginal.

**Possibly. I just checked my supplier. For a typical decoupling cap (such
as that used in a crossover) the cost of a regular 85oC rated part was
AUS$0.68c each. For a high grade, 105oC part, the cost was $7.19 each.
(Same values) Naturally, there is a range of prices between these values.

In my searching, the range of prices was US$0.68 for the 85 degree part
versus US $0.35 for the 105 degree part. Yes, the higher temperature
product was cheaper!

[Trevor Wilson[_2_]]

"Arny Krueger" wrote in message
...

"Trevor Wilson" wrote in message
...

"Arny Krueger" wrote in message
. ..

"MiNe 109" wrote in message
...
In article ,
"Trevor Wilson" wrote:

"MiNe 109" wrote in message
...
In article

et,
Jenn wrote:

...of listening to music through home audio equipment. In about 35
years, for all of the gear I've had, from Sears on up, I've had a
power
switch on a SAE amp go out after 3 years of use in 1983. That's
it. Am
I lucky, or do you have similar experiences?

I was surprised to learn that my Linn electronic crossover required
more
than one hundred fifty replacement capacitors. Then I found my Linn
amp
needed a similar action when I plugged in the newly repaired
crossover.

The capacitors on my LP12 power supply died a couple of years back.
I
wonder if these Linn capacitor failures are a coincidence.


**Read the specs on capacitors sometime. It's quite scarey.
Electrolytic
caps are usually rated to XXXX hrs @ 85oC or 105oC. The better the
cap, the
more hours and the higher the temp. Naturally, the cap is derated, as
the
temperature rises. A typical cap found in a domestic product would be
rated
for around 5,000 hours @ 85oC. A mil-spec cap might be typically
20,000
hours @ 105oC. The difference in cost would be substantial. Keep your
caps
cool. Fan cooling is best.

My repairman used mil-spec replacements for about the same price Linn
would have charged to renew the original parts.

He was probably marking those mil-spec parts up fantastically. In small
volumes, the actual additional cost of a more competent part obtained
competently is usually only marginal.

**Possibly. I just checked my supplier. For a typical decoupling cap
(such as that used in a crossover) the cost of a regular 85oC rated part
was AUS$0.68c each. For a high grade, 105oC part, the cost was $7.19
each. (Same values) Naturally, there is a range of prices between these
values.

In my searching, the range of prices was US$0.68 for the 85 degree part
versus US $0.35 for the 105 degree part. Yes, the higher temperature
product was cheaper!

**That is certainly possible. However, I was VERY specific in my search. I
wanted MIL-Spec or similar quality. That means at least 20,000 hours and low
ESR, along with the usual specs associated with high grade parts.

Trevor Wilson

[Trevor Wilson[_2_]]

"Arny Krueger" wrote in message
. ..

"MiNe 109" wrote in message
...
In article ,
"Arny Krueger" wrote:

"MiNe 109" wrote in message
...
In article ,
"Arny Krueger" wrote:

"MiNe 109" wrote in message
...

My repairman used mil-spec replacements for about the same price
Linn
would have charged to renew the original parts.

He was probably marking those mil-spec parts up fantastically. In
small
volumes, the actual additional cost of a more competent part
obtained
competently is usually only marginal.

For the crossover, he installed 150 caps for $250 and was finished
the
next day.

Very unlikely. There aren't 150 capactors in 10 speakers, let alone
1.

It's a three-way active crossover on a circuit board. I got a plastic
bag full of dead parts in exchange. There were also repairs to the
power
supply, so it's possible the total was of assorted parts.

Maybe 15 parts.

No, even an electronics novice such as myself can tell the difference
between a bag of fifteen parts and a bag of one hundred fifty.

An online forum post describes a similar Linn crossover: "Linn
definitely claim some correction for phase in the Isobarik Aktiv box,
it
has a lot of electronics in it. Including two rows of 8 stages of
something with a capactitor and two transistors" which were said "The
two neat rows of trannies are basically cascaded all pass phase shift
networks to give you time alignment between the hf & mf sections at
crossover point." The Kabers are three-way, so include more parts than
that.

There's only one way to describe a circuit board that small with 15 bad
parts on it: junk as built.

The number fifteen is your guess based on passive crossovers, so we can
move past this claim.

Well Stephen, you usual delusions of mind reading are in evidence as is
usual.

As for 'bad parts,' you must have missed Trevor's posts about the finite
life of electronic components. These may have been as much as twenty
years old, and because of damage to the power switch, run 24/7 for the
last few years.

I don't need Trevor to educate me about the reliability of electronic
parts.

**Actually, I suspect you do. Electrlytic capacitors begin wearing out, as
soon as the equipment is turned on. Many caps destined for domestic products
have a very short (published) life span. Certainly less than 5,000 hours. If
I was presented with a 20 year old piece of equipment, with a large number
of caps, some of which had failed, I would advise replacement of most/all
electros as a matter of course.The reason for this is that I do not like to
see my clients return with the same equipment, for similar faults, within a
year or two of service. I'd much prefer that my repair last AT LEAST as long
as the equipment had lasted to date. Preferably longer. As a rule, I always
use superior quality replacement caps, where possible.


The still-excessive failure rate may help explain Linn's continual
redesign of its active crossovers from discrete components to circuit
boards with plug-in modules to plug-in modules placed directly in the
power amp.

Failure of 150 parts in an electronic crossover, even after 20 years of
24/7 use is characteristic of junk-as-built.

**Nope. It is quite common. Ten years is about what we expect from a
permanent power supply in an old VCR. Cap failure is a normal event.
Particularly for products which operate at elevated temperatures. Even
quality brands like Sony and Panasonic are so afflicted. Quite a large
number of engineers appear to treat caps as if they are 'blcak box' passive
components, which are impervious to heat. They're wrong, of course.


Interesting that 'same price for better specs' translates to
'fantastic
markup' for you.

Stephen, can't read can you? Or is it that context means nothing to
you?
The above is irrelevant to what I said, and more strikingly, it is
irrelevant to what you said.

It's a paraphrase of what you said in reply to what I said. I agree
that
it didn't make sense in context.

You can buy motor oil cheaper in the store than at the mechanic's,
too.

Of course, but irrelevant.

Exactly relevant to the cost of replacement parts "obtained
competently"
by the tech vs the cost to the consumer installed as a repair.

That wasn't what I was talking about. I was talking about the
incremental
cost of a higher-spec part which is what you started out talking about.

Yes, I said I was able to get the higher-spec'd parts installed for the
supposed cost of a Linn renewal to original specs. Then you said the
repairman got a 'fantastic markup' which doesn't make sense,

It makes as much sense as you care to understand.

As things stand, the whole story is strange.

The number of parts (150 capacitors!) that were replaced was way out of
proportion to reality for either a passive or active crossover.

**Not necessarily. I've not sighted the crossover in question, but it is
entirely possible that Linn have used a large number of decoupling caps in
their design. I've worked on a few crossovers and some use rather prodigious
numbers of eletros in their design (usually as decoupling caps).

Form
example, there might be 35 capacitors per channel in an active crossover.
If even 25 percent failed after 20 years, it would be a disaster of
biblical proportions!

**Except that neither of us know what Linn have done and their reasons for
doing so.

Trevor Wilson

[Trevor Wilson[_2_]]

"ScottW" wrote in message
...

"Trevor Wilson" wrote in message
...

**Actually, I suspect you do. Electrlytic capacitors begin wearing out,
as soon as the equipment is turned on. Many caps destined for domestic
products have a very short (published) life span. Certainly less than
5,000 hours.

Couple of points.
1) These short lives are at very high temps. 80c.

**85oC, actually.

No domestic product has temps that high...they'd have to
provide thermal shield to meet U/L safety requirements.
So the cap life doubles with every 10c decrease in temp.
Get down to a quite reasonable 40c and you're looking
at 40,000 hours...

**Correct. Many domestic products subject caps to temps as high as 60oC,
however.


2) The primary wearout failure is loss electrolyte causing a
a drop in capacitance with failure usually spec'd at 80% of
rated value. Most electrolytics are applied as filters which
aren't terribly value sensitive.

**Not quite. There are several factors which suffer as a cap ages.
Primarily, it is ESR (Equivalent Series Resistance), followed by
capacitance. Often a cap will measure close for specified capacistance, but
an unnacceptably high value for ESR.

Electrolytics in a crossovers value sensitive applications would
be very poor design.

**Indeed. I've not examined the Linn design, but I very much doubt that
electros would be used in such applications.




If I was presented with a 20 year old piece of equipment, with a large
number of caps, some of which had failed, I would advise replacement of
most/all electros as a matter of course.The reason for this is that I do
not like to see my clients return with the same equipment, for similar
faults, within a year or two of service. I'd much prefer that my repair
last AT LEAST as long as the equipment had lasted to date. Preferably
longer. As a rule, I always use superior quality replacement caps, where
possible.


The still-excessive failure rate may help explain Linn's continual
redesign of its active crossovers from discrete components to circuit
boards with plug-in modules to plug-in modules placed directly in the
power amp.

Failure of 150 parts in an electronic crossover, even after 20 years of
24/7 use is characteristic of junk-as-built.

**Nope. It is quite common. Ten years is about what we expect from a
permanent power supply in an old VCR. Cap failure is a normal event.
Particularly for products which operate at elevated temperatures. Even
quality brands like Sony and Panasonic are so afflicted. Quite a large
number of engineers appear to treat caps as if they are 'blcak box'
passive components, which are impervious to heat. They're wrong, of
course.


Interesting that 'same price for better specs' translates to
'fantastic
markup' for you.

Stephen, can't read can you? Or is it that context means nothing to
you?
The above is irrelevant to what I said, and more strikingly, it is
irrelevant to what you said.

It's a paraphrase of what you said in reply to what I said. I agree
that
it didn't make sense in context.

You can buy motor oil cheaper in the store than at the
mechanic's, too.

Of course, but irrelevant.

Exactly relevant to the cost of replacement parts "obtained
competently"
by the tech vs the cost to the consumer installed as a repair.

That wasn't what I was talking about. I was talking about the
incremental
cost of a higher-spec part which is what you started out talking
about.

Yes, I said I was able to get the higher-spec'd parts installed for the
supposed cost of a Linn renewal to original specs. Then you said the
repairman got a 'fantastic markup' which doesn't make sense,

It makes as much sense as you care to understand.

As things stand, the whole story is strange.

The number of parts (150 capacitors!) that were replaced was way out of
proportion to reality for either a passive or active crossover.

**Not necessarily. I've not sighted the crossover in question, but it is
entirely possible that Linn have used a large number of decoupling caps
in their design.
I've worked on a few crossovers and some use rather prodigious numbers of
eletros in their design (usually as decoupling caps).

Why is a dc block needed in an active crossover?

**I dunno. It's your strawman, you build it, you burn it down.


Anyway...electrolytics not being symmetrical with polarity are
an awful choice for an ac coupling/decoupling application.

**Huh? Coupling and DEcoupling are very different things. Electrolytic caps
are fine for DEcoupling. In fact, there are few suitable alternatives.
Provided they are suitably selected, they can also be fine for coupling, but
that would not be my preference.


See this guide.
http://www.electrocube.com/support/bullet3.asp

**Tell you what: Don't direct me to a site which has misleading information
and I won't tell your mom how to cook roadkill.

Trevor Wilson

[Trevor Wilson[_2_]]

"ScottW" wrote in message
...

"Trevor Wilson" wrote in message
...

"ScottW" wrote in message
...

"Trevor Wilson" wrote in message
...

**Actually, I suspect you do. Electrlytic capacitors begin wearing out,
as soon as the equipment is turned on. Many caps destined for domestic
products have a very short (published) life span. Certainly less than
5,000 hours.

Couple of points.
1) These short lives are at very high temps. 80c.

**85oC, actually.

No domestic product has temps that high...they'd have to
provide thermal shield to meet U/L safety requirements.
So the cap life doubles with every 10c decrease in temp.
Get down to a quite reasonable 40c and you're looking
at 40,000 hours...

**Correct. Many domestic products subject caps to temps as high as 60oC,
however.


2) The primary wearout failure is loss electrolyte causing a
a drop in capacitance with failure usually spec'd at 80% of
rated value. Most electrolytics are applied as filters which
aren't terribly value sensitive.

**Not quite. There are several factors which suffer as a cap ages.
Primarily, it is ESR (Equivalent Series Resistance), followed by
capacitance. Often a cap will measure close for specified capacistance,
but an unnacceptably high value for ESR.

See this nice paper on cap failure modes.
Capacitance and tan delta both decay as a function of the same
failure mechanism, electrolyte loss.

http://industrial.panasonic.com/www-...ABA0000TE4.pdf

**MUCH better cite than your earlier, misleading one. IME, ESR increases
long before capacitance decreases. Of coruse, what would I know? I've only
been servicing faulty equipment for several decades. Tell about your
experience. Do you, like me, use an ESR meter, as part of your test
equipment suite?



Electrolytics in a crossovers value sensitive applications would
be very poor design.

**Indeed. I've not examined the Linn design, but I very much doubt that
electros would be used in such applications.




If I was presented with a 20 year old piece of equipment, with a large
number of caps, some of which had failed, I would advise replacement of
most/all electros as a matter of course.The reason for this is that I
do not like to see my clients return with the same equipment, for
similar faults, within a year or two of service. I'd much prefer that
my repair last AT LEAST as long as the equipment had lasted to date.
Preferably longer. As a rule, I always use superior quality replacement
caps, where possible.


The still-excessive failure rate may help explain Linn's continual
redesign of its active crossovers from discrete components to circuit
boards with plug-in modules to plug-in modules placed directly in the
power amp.

Failure of 150 parts in an electronic crossover, even after 20 years
of 24/7 use is characteristic of junk-as-built.

**Nope. It is quite common. Ten years is about what we expect from a
permanent power supply in an old VCR. Cap failure is a normal event.
Particularly for products which operate at elevated temperatures. Even
quality brands like Sony and Panasonic are so afflicted. Quite a large
number of engineers appear to treat caps as if they are 'blcak box'
passive components, which are impervious to heat. They're wrong, of
course.


Interesting that 'same price for better specs' translates to
'fantastic
markup' for you.

Stephen, can't read can you? Or is it that context means nothing
to you?
The above is irrelevant to what I said, and more strikingly, it
is
irrelevant to what you said.

It's a paraphrase of what you said in reply to what I said. I
agree that
it didn't make sense in context.

You can buy motor oil cheaper in the store than at the
mechanic's, too.

Of course, but irrelevant.

Exactly relevant to the cost of replacement parts "obtained
competently"
by the tech vs the cost to the consumer installed as a repair.

That wasn't what I was talking about. I was talking about the
incremental
cost of a higher-spec part which is what you started out talking
about.

Yes, I said I was able to get the higher-spec'd parts installed for
the
supposed cost of a Linn renewal to original specs. Then you said the
repairman got a 'fantastic markup' which doesn't make sense,

It makes as much sense as you care to understand.

As things stand, the whole story is strange.

The number of parts (150 capacitors!) that were replaced was way out
of proportion to reality for either a passive or active crossover.

**Not necessarily. I've not sighted the crossover in question, but it
is entirely possible that Linn have used a large number of decoupling
caps in their design.
I've worked on a few crossovers and some use rather prodigious numbers
of eletros in their design (usually as decoupling caps).

Why is a dc block needed in an active crossover?

**I dunno. It's your strawman, you build it, you burn it down.

That is what is often referred to as decoupling here,
so it's your strawman.

**Decoupling is a universal term. It is used all over the planet. Except,
apparently, your little corner (and I don't mean the US). EVERYONE in the
electronics biz understands the terminology.




Anyway...electrolytics not being symmetrical with polarity are
an awful choice for an ac coupling/decoupling application.

**Huh? Coupling and DEcoupling are very different things.

OK.

Electrolytic caps are fine for DEcoupling.

exception being when AC amplitudes are larger than DC
bias.......depending on circuit requirements.

**Huh? Anyone designing a product using decoupling caps will have done so
taking the peak AC impressed on the DC level into account. Designers who do
not, tend to end up with a large number of premature failures.


In fact, there are few suitable alternatives.

Low cost/form factor equivalent alternatives...but there
are alternatives.

**OK, I'll bite. List them.


Provided they are suitably selected, they can also be fine for coupling,
but that would not be my preference.


See this guide.
http://www.electrocube.com/support/bullet3.asp

**Tell you what: Don't direct me to a site which has misleading
information and I won't tell your mom how to cook roadkill.

Lol....its film specialty shop and they have different guidelines
than your typical cap manufacturer for good reasons.

**I don't care. They are supplying you misleading and incorrect information.
I suggest you get your knowledge from a proper text book on the subject.

Don't tell us the designers who cook your caps don't cut corners
for board space as well?

**Of course. That is a big part of the problem. Lazy designers don't ensure
that caps are kept cool.

Trevor Wilson

[Arny Krueger]

"ScottW" wrote in message
...

"Trevor Wilson" wrote in message
...

**Actually, I suspect you do. Electrlytic capacitors begin wearing out,
as soon as the equipment is turned on. Many caps destined for domestic
products have a very short (published) life span. Certainly less than
5,000 hours.

Couple of points.

1) These short lives are at very high temps. 80c.
No domestic product has temps that high...they'd have to
provide thermal shield to meet U/L safety requirements.
So the cap life doubles with every 10c decrease in temp.
Get down to a quite reasonable 40c and you're looking
at 40,000 hours...

Agreed.

2) The primary wearout failure is loss electrolyte causing a
a drop in capacitance with failure usually spec'd at 80% of
rated value. Most electrolytics are applied as filters which
aren't terribly value sensitive.
Electrolytics in a crossovers value sensitive applications would
be very poor design.

Agreed.

If I was presented with a 20 year old piece of equipment, with a large
number of caps, some of which had failed, I would advise replacement of
most/all electros as a matter of course.The reason for this is that I do
not like to see my clients return with the same equipment, for similar
faults, within a year or two of service. I'd much prefer that my repair
last AT LEAST as long as the equipment had lasted to date. Preferably
longer. As a rule, I always use superior quality replacement caps, where
possible.

Agreed up to the point where a ludicrous number of parts are involved, like
150 caps in a simple stereo active crossover.

The still-excessive failure rate may help explain Linn's continual
redesign of its active crossovers from discrete components to circuit
boards with plug-in modules to plug-in modules placed directly in the
power amp.

Failure of 150 parts in an electronic crossover, even after 20 years of
24/7 use is characteristic of junk-as-built.

**Nope. It is quite common. Ten years is about what we expect from a
permanent power supply in an old VCR.

Irrelevant because VCRs aren't comparable to electronic crossovers. Every
VCR I've scrapped had worn-out heads.

Cap failure is a normal event. Particularly for products which operate
at elevated temperatures. Even quality brands like Sony and Panasonic
are so afflicted. Quite a large number of engineers appear to treat caps
as if they are 'blcak box' passive components, which are impervious to
heat. They're wrong, of course.

Come on Trevor, this is a high end electronic crossover, not a power amp or
piece of consumer mid-fi.

Interesting that 'same price for better specs' translates to
'fantastic
markup' for you.

Stephen, can't read can you? Or is it that context means nothing to
you?
The above is irrelevant to what I said, and more strikingly, it is
irrelevant to what you said.

It's a paraphrase of what you said in reply to what I said. I agree
that
it didn't make sense in context.

You can buy motor oil cheaper in the store than at the
mechanic's, too.

Of course, but irrelevant.

Exactly relevant to the cost of replacement parts "obtained
competently"
by the tech vs the cost to the consumer installed as a repair.

That wasn't what I was talking about. I was talking about the
incremental
cost of a higher-spec part which is what you started out talking
about.

Yes, I said I was able to get the higher-spec'd parts installed for the
supposed cost of a Linn renewal to original specs. Then you said the
repairman got a 'fantastic markup' which doesn't make sense,

It makes as much sense as you care to understand.

As things stand, the whole story is strange.

The number of parts (150 capacitors!) that were replaced was way out of
proportion to reality for either a passive or active crossover.

**Not necessarily. I've not sighted the crossover in question, but it is
entirely possible that Linn have used a large number of decoupling caps
in their design.

All things are possible, but 150 decoupling caps in an simpe 2-channel
electronic crossover is ludicrous.

I've worked on a few crossovers and some use rather prodigious numbers of
eletros in their design (usually as decoupling caps).

I guess some people do crazy things. For example, look at the power supply
caps in a ME power amp!

Why is a dc block needed in an active crossover?

No, these are decoupling caps, for the power supply. A large number of
electrolytic decoupling caps are not needed - the decoupling caps that show
up in any volume at all are ceramics or film caps, and those typically have
much longer lives than electrolytics.

Anyway...electrolytics not being symmetrical with polarity are
an awful choice for an ac coupling/decoupling application.

Not true.

See this guide.
http://www.electrocube.com/support/bullet3.asp

I don't see where this document supports your claims about electrolytics
being bad for coupling, Scott.

[Arny Krueger]

"Trevor Wilson" wrote in message
...


**Of course. That is a big part of the problem. Lazy designers don't
ensure that caps are kept cool.

Red herring in the context of the OP. Keeping caps cool in an electronic
crossover is rarely if ever an issue.

[Arny Krueger]

"MiNe 109" wrote in message
...
In article ,
"Arny Krueger" wrote:

Agreed up to the point where a ludicrous number of parts are involved,
like
150 caps in a simple stereo active crossover.

The Linn probably isn't "a simple stereo active crossover".

Actually, absent a schematic, we don't know one way or the other. Linn is
well known for hype.

There's some complicated phase-correction if it's like the other Linn
crossover whose
description I quoted.

Unecessarily complicated = bad design. Phase correction even overkilled
doesn't take 100+ caps.

It also has separate level controls by internal switching.

That need not add any caps at all.

The Rane crossover I've been using as a benchmark obtains its desirable
phase characteristics by means of a sophisticated design that does add a few
more parts, like maybe 4 op amps, 8 caps and 8 resistors.

[Arny Krueger]

"MiNe 109" wrote in message
...
In article ,
"Arny Krueger" wrote:

"MiNe 109" wrote in message
...
In article ,
"Arny Krueger" wrote:

Agreed up to the point where a ludicrous number of parts are involved,
like
150 caps in a simple stereo active crossover.

The Linn probably isn't "a simple stereo active crossover".

Actually, absent a schematic, we don't know one way or the other. Linn is
well known for hype.

Or you could pop the top and look at it.

Yeah, the one I have right here. NOT!

There's a bunch of parts in there.

Yup, that's an exact number: "a bunch of parts".

There's some complicated phase-correction if it's like the other Linn
crossover whose
description I quoted.

Unecessarily complicated = bad design. Phase correction even overkilled
doesn't take 100+ caps.

Perhaps that's why Linn developed plug-in cards.

Perhaps not. Most likely: irrelevant.

It also has separate level controls by internal switching.

That need not add any caps at all.

The Rane crossover I've been using as a benchmark obtains its desirable
phase characteristics by means of a sophisticated design that does add a
few
more parts, like maybe 4 op amps, 8 caps and 8 resistors.

I'm sure it works fine.

The point is, it doesn't take 150+ decoupling caps to make a very, very good
crossover.

[Arny Krueger]

"ScottW" wrote in message
oups.com...
On Oct 17, 5:54 am, "Arny Krueger" wrote:
"MiNe 109" wrote in message

...

In article ,
"Arny Krueger" wrote:

Agreed up to the point where a ludicrous number of parts are involved,
like
150 caps in a simple stereo active crossover.
The Linn probably isn't "a simple stereo active crossover".

Actually, absent a schematic, we don't know one way or the other. Linn is
well known for hype.

There's some complicated phase-correction if it's like the other Linn
crossover whose
description I quoted.

Unecessarily complicated = bad design. Phase correction even overkilled
doesn't take 100+ caps.

It also has separate level controls by internal switching.

That need not add any caps at all.

The Rane crossover I've been using as a benchmark obtains its desirable
phase characteristics by means of a sophisticated design that does add a
few
more parts, like maybe 4 op amps, 8 caps and 8 resistors.

Which one? All their non-digital active crossovers use 4th order L-
R filters but no additional phase correction AFAICT.

Read what I said - "maintains desirable phase characteristic". Didn't say
there was any correction provided or needed.

[Trevor Wilson[_2_]]

"ScottW" wrote in message
ups.com...
On Oct 16, 10:29 pm, "Trevor Wilson"
wrote:
"ScottW" wrote in message

...







"Trevor Wilson" wrote in message
...

"ScottW" wrote in message
...

"Trevor Wilson" wrote in message
...

**Actually, I suspect you do. Electrlytic capacitors begin wearing
out,
as soon as the equipment is turned on. Many caps destined for
domestic
products have a very short (published) life span. Certainly less
than
5,000 hours.

Couple of points.
1) These short lives are at very high temps. 80c.

**85oC, actually.

No domestic product has temps that high...they'd have to
provide thermal shield to meet U/L safety requirements.
So the cap life doubles with every 10c decrease in temp.
Get down to a quite reasonable 40c and you're looking
at 40,000 hours...

**Correct. Many domestic products subject caps to temps as high as
60oC,
however.

2) The primary wearout failure is loss electrolyte causing a
a drop in capacitance with failure usually spec'd at 80% of
rated value. Most electrolytics are applied as filters which
aren't terribly value sensitive.

**Not quite. There are several factors which suffer as a cap ages.
Primarily, it is ESR (Equivalent Series Resistance), followed by
capacitance. Often a cap will measure close for specified
capacistance,
but an unnacceptably high value for ESR.

See this nice paper on cap failure modes.
Capacitance and tan delta both decay as a function of the same
failure mechanism, electrolyte loss.

http://industrial.panasonic.com/www-...ABA0000TE4.pdf

**MUCH better cite than your earlier, misleading one. IME, ESR increases
long before capacitance decreases. Of coruse, what would I know?

It's proportional. They both follow their curves.
Its a numbers game with initial ESR values being small so any change
is a significanct percentage while initial capacitance values are
large so any shift is small as a percentage.

I've only
been servicing faulty equipment for several decades. Tell about your
experience. Do you, like me, use an ESR meter, as part of your test
equipment suite?

I wasn't servicing gear...I was managing a lab which qualified caps
(among many other components) for military (ship borne computers) and
hi reliability mainframe applications. It was some time ago, but the
technology hasn't changed much except for the emergence of nonpolar
electrolytics. The work horse of our test lab was an HP LCR meter.
4284 comes to mind...You have the equivalent to one of those in your
shop?

**My two, main capacitor measurement devices a
* Custom made ESR meter. Regularly calibrated.
* Data Precision 938 capacitor meter. Regularly calibrated.





Electrolytics in a crossovers value sensitive applications would
be very poor design.

**Indeed. I've not examined the Linn design, but I very much doubt
that
electros would be used in such applications.

If I was presented with a 20 year old piece of equipment, with a
large
number of caps, some of which had failed, I would advise replacement
of
most/all electros as a matter of course.The reason for this is that
I
do not like to see my clients return with the same equipment, for
similar faults, within a year or two of service. I'd much prefer
that
my repair last AT LEAST as long as the equipment had lasted to date.
Preferably longer. As a rule, I always use superior quality
replacement
caps, where possible.

The still-excessive failure rate may help explain Linn's continual
redesign of its active crossovers from discrete components to
circuit
boards with plug-in modules to plug-in modules placed directly in
the
power amp.

Failure of 150 parts in an electronic crossover, even after 20
years
of 24/7 use is characteristic of junk-as-built.

**Nope. It is quite common. Ten years is about what we expect from a
permanent power supply in an old VCR. Cap failure is a normal event.
Particularly for products which operate at elevated temperatures.
Even
quality brands like Sony and Panasonic are so afflicted. Quite a
large
number of engineers appear to treat caps as if they are 'blcak box'
passive components, which are impervious to heat. They're wrong, of
course.

Interesting that 'same price for better specs' translates to
'fantastic
markup' for you.

Stephen, can't read can you? Or is it that context means
nothing
to you?
The above is irrelevant to what I said, and more strikingly,
it
is
irrelevant to what you said.

It's a paraphrase of what you said in reply to what I said. I
agree that
it didn't make sense in context.

You can buy motor oil cheaper in the store than at the
mechanic's, too.

Of course, but irrelevant.

Exactly relevant to the cost of replacement parts "obtained
competently"
by the tech vs the cost to the consumer installed as a repair.

That wasn't what I was talking about. I was talking about the
incremental
cost of a higher-spec part which is what you started out talking
about.

Yes, I said I was able to get the higher-spec'd parts installed
for
the
supposed cost of a Linn renewal to original specs. Then you said
the
repairman got a 'fantastic markup' which doesn't make sense,

It makes as much sense as you care to understand.

As things stand, the whole story is strange.

The number of parts (150 capacitors!) that were replaced was way
out
of proportion to reality for either a passive or active crossover.

**Not necessarily. I've not sighted the crossover in question, but
it
is entirely possible that Linn have used a large number of
decoupling
caps in their design.
I've worked on a few crossovers and some use rather prodigious
numbers
of eletros in their design (usually as decoupling caps).

Why is a dc block needed in an active crossover?

**I dunno. It's your strawman, you build it, you burn it down.

That is what is often referred to as decoupling here,
so it's your strawman.

**Decoupling is a universal term. It is used all over the planet. Except,
apparently, your little corner (and I don't mean the US). EVERYONE in the
electronics biz understands the terminology.

Sorry.. its a microwave thing. In microwave and RF apps the
requirements
for DC blocks and decoupling are the same...low reactance at
the frequency of operation....so the terms get interchanged when
specing parts.
My mistake....Jenn please take note.

**Your mistake is recognised.





Anyway...electrolytics not being symmetrical with polarity are
an awful choice for an ac coupling/decoupling application.

**Huh? Coupling and DEcoupling are very different things.

OK.

Electrolytic caps are fine for DEcoupling.

exception being when AC amplitudes are larger than DC
bias.......depending on circuit requirements.

**Huh? Anyone designing a product using decoupling caps will have done so
taking the peak AC impressed on the DC level into account. Designers who
do
not, tend to end up with a large number of premature failures.

Many electrolytics are now advertised as nonpolar for use in these
applications.

http://www.maplin.co.uk/Module.aspx?...SO&U=strat1 5

IME...which is dated...their performance is not symmetrical with bias
polarity.

**I've NEVER seen such caps used for decoupling. And it is decoupling that
we are discussing.


In any case...they won't fail if reverse biased...but they are not a
preferred solution
thought I suspect speakers are full of these caps.

**Many are. And they fail regularly. Most have a published life of around
2,000 hours @ 85oC. With their 50 or 100 Volt ratings, failures are common
with listeners who enjoy loud music.





In fact, there are few suitable alternatives.

Low cost/form factor equivalent alternatives...but there
are alternatives.

**OK, I'll bite. List them.

Poly metal film is the most common.

**Completely impractical for decoupling. The smallest decoupling caps are
around 1uF. More usually, they range well up to 470uF. Pack a few dozen film
caps into a case and there won't be much room for anything else. Then
there's the cost. 1uF film caps are MUCH more expensive than electros.

Big, expensive but better for bipolar applications.

**Of course, but we're discussing decoupling caps.





Provided they are suitably selected, they can also be fine for
coupling,
but that would not be my preference.

See this guide.
http://www.electrocube.com/support/bullet3.asp

**Tell you what: Don't direct me to a site which has misleading
information and I won't tell your mom how to cook roadkill.

Lol....its film specialty shop and they have different guidelines
than your typical cap manufacturer for good reasons.

**I don't care. They are supplying you misleading and incorrect
information.
I suggest you get your knowledge from a proper text book on the subject.

I'll bite....list one.

**The Art of Electronics - Horowitz, is one I've used.



Don't tell us the designers who cook your caps don't cut corners
for board space as well?

**Of course. That is a big part of the problem. Lazy designers don't
ensure
that caps are kept cool.

Or use larger sized components that might provide more ideal
electrical characteristics.

Here's an example. I open my Quads and on the input is a filter with
a 220 uf electrolytic with a 1.5ohm 10 watt (maybe more) wirewound
resistor
on the input. The resistor are zip tied to the side of the cap.
How's that for stupid?

**It sure is dumb.


Anyway, on both speakers the reisistor is cooked and cracked.
I replaced the network with a poly cap and new WW resistors...subtle
change
in sound. I had to use a 1 ohm in series with 2, 1 ohms in parallel
to get the
right value. I notice after a year the leading series resistor is
cracked and burnt.
Things shouldn't be getting that hot...so maybe it was defective and
intermittent.

So now I got a 35 watt low inductance metal oxides in a TO220 packages
and heatsink. Suckers won't get hot now....but I think the low
inductance made a difference...maybe the balance is just better...hard
to tell, but I like it.

**There you go. Lazy designers have caused you problems. I deal with their
mistakes every day. I sometimes wish those idiots would consult with techs
sometime.

Trevor Wilson

[Trevor Wilson[_2_]]

"ScottW" wrote in message
oups.com...
On Oct 17, 1:40 pm, "Trevor Wilson"
wrote:
"ScottW" wrote in message
In fact, there are few suitable alternatives.

Low cost/form factor equivalent alternatives...but there
are alternatives.

**OK, I'll bite. List them.

Poly metal film is the most common.

**Completely impractical for decoupling. The smallest decoupling caps are
around 1uF. More usually, they range well up to 470uF.

In power supplies.....which is a fine place for electrolytics.
I should probably start looking into replacing the electrolytics
in my Krell....that beast gets hot.

**Unless it has fans, yes. You should consider replacing all the small
electros, at least. IME, these guys suffer long before the big guys. Of
course, it depends on the age of your amp and how much it gets used.


Anyway in the case of signal decoupling...which is probably
a rare app in audio now that I think about it...
electrolytics aren't always the best choice but due to size
and cost are still used.


Pack a few dozen film
caps into a case and there won't be much room for anything else. Then
there's the cost. 1uF film caps are MUCH more expensive than electros.

Big, expensive but better for bipolar applications.

**Of course, but we're discussing decoupling caps.

So where would that occurr in audio outside of a power supply?

**It doesn't. At least not strictly speaking. Most manufacturers decouple
power supply rails at each OP amp, or amplifier stage within a product. For
instance: A typical (not hugely expensive) CD player will contain between 4
and 8 OP amps. Each OP amp will have two power supply rails. Each rail at
each OP amp will have a capacitor to decouple that rail. Good designers
place the caps VERY close to the OP amps. Caps would typically range from
22uF to 220uF in this application. High end CD players (often fitted with
balanced outputs) may have between 8 and 16 OP amps.Or more, if headphone
amps and volume controlled output are used. A DVD or SACD player may have
even more, since 5.1 channels may need to be accommodated for.

Trevor Wilson

[Trevor Wilson[_2_]]

"Arny Krueger" wrote in message
. ..

"ScottW" wrote in message
...

"Trevor Wilson" wrote in message
...

**Actually, I suspect you do. Electrlytic capacitors begin wearing out,
as soon as the equipment is turned on. Many caps destined for domestic
products have a very short (published) life span. Certainly less than
5,000 hours.

Couple of points.

1) These short lives are at very high temps. 80c.
No domestic product has temps that high...they'd have to
provide thermal shield to meet U/L safety requirements.
So the cap life doubles with every 10c decrease in temp.
Get down to a quite reasonable 40c and you're looking
at 40,000 hours...

Agreed.

2) The primary wearout failure is loss electrolyte causing a
a drop in capacitance with failure usually spec'd at 80% of
rated value. Most electrolytics are applied as filters which
aren't terribly value sensitive.
Electrolytics in a crossovers value sensitive applications would
be very poor design.

Agreed.

If I was presented with a 20 year old piece of equipment, with a large
number of caps, some of which had failed, I would advise replacement of
most/all electros as a matter of course.The reason for this is that I do
not like to see my clients return with the same equipment, for similar
faults, within a year or two of service. I'd much prefer that my repair
last AT LEAST as long as the equipment had lasted to date. Preferably
longer. As a rule, I always use superior quality replacement caps, where
possible.

Agreed up to the point where a ludicrous number of parts are involved,
like 150 caps in a simple stereo active crossover.

**You keep parrotting this statement, like it makes sense. Neither you, nor
I have seen the product in question. Let's examine what is involved (worst
case scenario):

Linn probably use OP amps in the unit. It is, as I understand it, a three
way crossover. If it uses balanced circuitry, the complexity and the number
of caps could be prodigious. Each OP amp will have a pair of decoupling
caps. The power supply would likely contain 6 or 8 caps, at a bare minimum.
Etc, etc. 150 caps is within the realm of possibility.


The still-excessive failure rate may help explain Linn's continual
redesign of its active crossovers from discrete components to circuit
boards with plug-in modules to plug-in modules placed directly in the
power amp.

Failure of 150 parts in an electronic crossover, even after 20 years of
24/7 use is characteristic of junk-as-built.

**Nope. It is quite common. Ten years is about what we expect from a
permanent power supply in an old VCR.

Irrelevant because VCRs aren't comparable to electronic crossovers.

**Sure they are. They use electrolytic caps and are permanently powered.

Every
VCR I've scrapped had worn-out heads.

**I suggest you examine some 20 year old VCRs. Don't forget: Stephen's
crossover is 20 years old.


Cap failure is a normal event. Particularly for products which operate
at elevated temperatures. Even quality brands like Sony and Panasonic
are so afflicted. Quite a large number of engineers appear to treat
caps as if they are 'blcak box' passive components, which are
impervious to heat. They're wrong, of course.

Come on Trevor, this is a high end electronic crossover, not a power amp
or piece of consumer mid-fi.

**So? I've measured transistors in a preamp operating at 75oC. And there was
no ventilation holes in the case either. Of course, that was an issue of
very abd design. Still, I've seen soem pretty dumb design choices in mass
market products. In fact, on Tuesday, I worked on a cheap Sony CD player,
where a powewr supply cap was stupidly placed adjacent to a hot running
regulator. It was stuffed.


Interesting that 'same price for better specs' translates to
'fantastic
markup' for you.

Stephen, can't read can you? Or is it that context means nothing
to you?
The above is irrelevant to what I said, and more strikingly, it is
irrelevant to what you said.

It's a paraphrase of what you said in reply to what I said. I agree
that
it didn't make sense in context.

You can buy motor oil cheaper in the store than at the
mechanic's, too.

Of course, but irrelevant.

Exactly relevant to the cost of replacement parts "obtained
competently"
by the tech vs the cost to the consumer installed as a repair.

That wasn't what I was talking about. I was talking about the
incremental
cost of a higher-spec part which is what you started out talking
about.

Yes, I said I was able to get the higher-spec'd parts installed for
the
supposed cost of a Linn renewal to original specs. Then you said the
repairman got a 'fantastic markup' which doesn't make sense,

It makes as much sense as you care to understand.

As things stand, the whole story is strange.

The number of parts (150 capacitors!) that were replaced was way out of
proportion to reality for either a passive or active crossover.

**Not necessarily. I've not sighted the crossover in question, but it is
entirely possible that Linn have used a large number of decoupling caps
in their design.

All things are possible, but 150 decoupling caps in an simpe 2-channel
electronic crossover is ludicrous.

**Have you examined the crossover? I haven't. I can conceive of the
possibilty that 150 caps were used. It is an analogue, three way crossover
and it is 20 years old, don't forget.


I've worked on a few crossovers and some use rather prodigious numbers
of eletros in their design (usually as decoupling caps).

I guess some people do crazy things. For example, look at the power supply
caps in a ME power amp!

**It seems your memory is faulty. I will explain why so many caps are used.

* ME amps use no Global NFB. As a consequence, their quality is heavily
dependent on power supply quality.
* Capacitors possess several paramaters which are of interest to designers:
* Capacitance.
* Ripple current rating.
* ESR (Equivalent Series Resistance)
* ESL (Equivalent Series Inductance)
Using a large number of capacitors acheives several things for the
manufacturer:
* Due to the packing efficiency of a large number of small caps,
more capacitance can be squeezed into a given chassis size, than several
large (round) caps. The effect, if you like, is to have a large, almost
rectangular block of caps.
* Ripple current is increased massively, thus enhancing the life
span of the caps.
* ESR is reduced, due to the large number of paralleled caps.
* ESL is reduced due to the large number of paralleled caps.
* A side benefit has been the increased longevity of the caps, due to the
both the paralleled nature of the caps and the fan cooling used in later
models.



Why is a dc block needed in an active crossover?

No, these are decoupling caps, for the power supply. A large number of
electrolytic decoupling caps are not needed - the decoupling caps that
show up in any volume at all are ceramics or film caps, and those
typically have much longer lives than electrolytics.

**Nope. Most domestic products use electros as decoupling elements.
Sometimes, these will be bypassed with small value film caps as well.


Anyway...electrolytics not being symmetrical with polarity are
an awful choice for an ac coupling/decoupling application.

Not true.

**Agreed.


See this guide.
http://www.electrocube.com/support/bullet3.asp

I don't see where this document supports your claims about electrolytics
being bad for coupling, Scott.

**Also agreed.

Trevor Wilson

[Arny Krueger]

"Trevor Wilson" wrote in message
...

**It doesn't. At least not strictly speaking. Most manufacturers decouple
power supply rails at each OP amp, or amplifier stage within a product.

So far, so good.

For instance: A typical (not hugely expensive) CD player will contain
between 4 and 8 OP amps.

Not lately.

A typical modern CD player will probably have just one op amp - the output
buffer. Why would it need more?

Each OP amp will have two power supply rails.

Each rail at each OP amp will have a capacitor to decouple that rail.

Well really, its more like a bypass cap.

Good designers place the caps VERY close to the OP amps.

So far, so good.

Caps would typically range from 22uF to 220uF in this application.

Nonsense. The power supply bypass caps at the op amps might be 0.05 or 0.1
uF, usually ceramics.

High end CD players (often fitted with balanced outputs) may have between
8 and 16 OP amps.

Nahh, more likely they have no op amps, and rely on discrete output stages.

Or more, if headphone amps and volume controlled output are used. A DVD
or SACD player may have even more, since 5.1 channels may need to be
accommodated for.

As a rule, only SACD and DVD-A players actually have more than 2 analog
outputs. Your typical CD or DVD player has 2 analog outputs and one or two
digital outputs.

[Arny Krueger]

"ScottW" wrote in message
ups.com...
On Oct 17, 1:07 pm, "Arny Krueger" wrote:
"ScottW" wrote in message

oups.com...





On Oct 17, 5:54 am, "Arny Krueger" wrote:
"MiNe 109" wrote in message

...

In article ,
"Arny Krueger" wrote:

Agreed up to the point where a ludicrous number of parts are
involved,
like
150 caps in a simple stereo active crossover.
The Linn probably isn't "a simple stereo active crossover".

Actually, absent a schematic, we don't know one way or the other. Linn
is
well known for hype.

There's some complicated phase-correction if it's like the other
Linn
crossover whose
description I quoted.

Unecessarily complicated = bad design. Phase correction even
overkilled
doesn't take 100+ caps.

It also has separate level controls by internal switching.

That need not add any caps at all.

The Rane crossover I've been using as a benchmark obtains its
desirable
phase characteristics by means of a sophisticated design that does add
a
few
more parts, like maybe 4 op amps, 8 caps and 8 resistors.

Which one? All their non-digital active crossovers use 4th order L-
R filters but no additional phase correction AFAICT.

Read what I said - "maintains desirable phase characteristic".

By means of a sophisticated design that does add a few more
parts......

So what do these parts do besides implement a 4th order L-R filter?

That is it.

What other 24 db/octave filter is used in audio that is less
sophisticated than yours?

The ones that don't provide continuously-variable frequency control, and the
ones that don't control both channels with one potentiometer.

[Arny Krueger]

"Trevor Wilson" wrote in message
...

"Arny Krueger" wrote in message
. ..

"ScottW" wrote in message
...

"Trevor Wilson" wrote in message
...

**Actually, I suspect you do. Electrlytic capacitors begin wearing out,
as soon as the equipment is turned on. Many caps destined for domestic
products have a very short (published) life span. Certainly less than
5,000 hours.

Couple of points.

1) These short lives are at very high temps. 80c.
No domestic product has temps that high...they'd have to
provide thermal shield to meet U/L safety requirements.
So the cap life doubles with every 10c decrease in temp.
Get down to a quite reasonable 40c and you're looking
at 40,000 hours...

Agreed.

2) The primary wearout failure is loss electrolyte causing a
a drop in capacitance with failure usually spec'd at 80% of
rated value. Most electrolytics are applied as filters which
aren't terribly value sensitive.
Electrolytics in a crossovers value sensitive applications would
be very poor design.

Agreed.

If I was presented with a 20 year old piece of equipment, with a large
number of caps, some of which had failed, I would advise replacement of
most/all electros as a matter of course.The reason for this is that I
do not like to see my clients return with the same equipment, for
similar faults, within a year or two of service. I'd much prefer that
my repair last AT LEAST as long as the equipment had lasted to date.
Preferably longer. As a rule, I always use superior quality replacement
caps, where possible.

Agreed up to the point where a ludicrous number of parts are involved,
like 150 caps in a simple stereo active crossover.

**You keep parrotting this statement, like it makes sense. Neither you,
nor I have seen the product in question. Let's examine what is involved
(worst case scenario):

Linn probably use OP amps in the unit. It is, as I understand it, a three
way crossover. If it uses balanced circuitry, the complexity and the
number of caps could be prodigious. Each OP amp will have a pair of
decoupling caps. The power supply would likely contain 6 or 8 caps, at a
bare minimum. Etc, etc. 150 caps is within the realm of possibility.


The still-excessive failure rate may help explain Linn's continual
redesign of its active crossovers from discrete components to circuit
boards with plug-in modules to plug-in modules placed directly in the
power amp.

Failure of 150 parts in an electronic crossover, even after 20 years
of 24/7 use is characteristic of junk-as-built.

**Nope. It is quite common. Ten years is about what we expect from a
permanent power supply in an old VCR.

Irrelevant because VCRs aren't comparable to electronic crossovers.

**Sure they are. They use electrolytic caps and are permanently powered.

Every
VCR I've scrapped had worn-out heads.

**I suggest you examine some 20 year old VCRs. Don't forget: Stephen's
crossover is 20 years old.


Cap failure is a normal event. Particularly for products which operate
at elevated temperatures. Even quality brands like Sony and Panasonic
are so afflicted. Quite a large number of engineers appear to treat
caps as if they are 'blcak box' passive components, which are
impervious to heat. They're wrong, of course.

Come on Trevor, this is a high end electronic crossover, not a power amp
or piece of consumer mid-fi.

**So? I've measured transistors in a preamp operating at 75oC. And there
was no ventilation holes in the case either. Of course, that was an issue
of very abd design. Still, I've seen soem pretty dumb design choices in
mass market products. In fact, on Tuesday, I worked on a cheap Sony CD
player, where a powewr supply cap was stupidly placed adjacent to a hot
running regulator. It was stuffed.


Interesting that 'same price for better specs' translates to
'fantastic
markup' for you.

Stephen, can't read can you? Or is it that context means nothing
to you?
The above is irrelevant to what I said, and more strikingly, it
is
irrelevant to what you said.

It's a paraphrase of what you said in reply to what I said. I
agree that
it didn't make sense in context.

You can buy motor oil cheaper in the store than at the
mechanic's, too.

Of course, but irrelevant.

Exactly relevant to the cost of replacement parts "obtained
competently"
by the tech vs the cost to the consumer installed as a repair.

That wasn't what I was talking about. I was talking about the
incremental
cost of a higher-spec part which is what you started out talking
about.

Yes, I said I was able to get the higher-spec'd parts installed for
the
supposed cost of a Linn renewal to original specs. Then you said the
repairman got a 'fantastic markup' which doesn't make sense,

It makes as much sense as you care to understand.

As things stand, the whole story is strange.

The number of parts (150 capacitors!) that were replaced was way out
of proportion to reality for either a passive or active crossover.

**Not necessarily. I've not sighted the crossover in question, but it
is entirely possible that Linn have used a large number of decoupling
caps in their design.

All things are possible, but 150 decoupling caps in an simpe 2-channel
electronic crossover is ludicrous.

**Have you examined the crossover? I haven't. I can conceive of the
possibilty that 150 caps were used. It is an analogue, three way crossover
and it is 20 years old, don't forget.


I've worked on a few crossovers and some use rather prodigious numbers
of eletros in their design (usually as decoupling caps).

I guess some people do crazy things. For example, look at the power
supply caps in a ME power amp!

**It seems your memory is faulty. I will explain why so many caps are
used.

* ME amps use no Global NFB.

As I said, some people do crazy things. Not using loop NFB in a power amp is
a genuinely crazy thing. Almost no modern power amps lack loop NFB.


Why is a dc block needed in an active crossover?

No, these are decoupling caps, for the power supply. A large number of
electrolytic decoupling caps are not needed - the decoupling caps that
show up in any volume at all are ceramics or film caps, and those
typically have much longer lives than electrolytics.

**Nope. Most domestic products use electros as decoupling elements.

Nonsense. Check the schematics at the Rane site - they are typical.

Sometimes, these will be bypassed with small value film caps as well.

The bypass caps are often needed. Power supply decoupling for most op amps
is silly and rarely done in audio gear outside of the wasteful high end.

[Trevor Wilson[_2_]]

"ScottW" wrote in message
ups.com...
On Oct 17, 2:31 pm, "Trevor Wilson"
wrote:
"ScottW" wrote in message

oups.com...





On Oct 17, 1:40 pm, "Trevor Wilson"
wrote:
"ScottW" wrote in message
In fact, there are few suitable alternatives.

Low cost/form factor equivalent alternatives...but there
are alternatives.

**OK, I'll bite. List them.

Poly metal film is the most common.

**Completely impractical for decoupling. The smallest decoupling caps
are
around 1uF. More usually, they range well up to 470uF.

In power supplies.....which is a fine place for electrolytics.
I should probably start looking into replacing the electrolytics
in my Krell....that beast gets hot.

**Unless it has fans, yes. You should consider replacing all the small
electros, at least. IME, these guys suffer long before the big guys. Of
course, it depends on the age of your amp and how much it gets used.







Anyway in the case of signal decoupling...which is probably
a rare app in audio now that I think about it...
electrolytics aren't always the best choice but due to size
and cost are still used.

Pack a few dozen film
caps into a case and there won't be much room for anything else. Then
there's the cost. 1uF film caps are MUCH more expensive than electros.

Big, expensive but better for bipolar applications.

**Of course, but we're discussing decoupling caps.

So where would that occurr in audio outside of a power supply?

**It doesn't. At least not strictly speaking. Most manufacturers decouple
power supply rails at each OP amp,

All our designs do the same...but none use electrolytics to decouple
at surface mount IC power leads. A ceramic that is very close to the
leads is more effective.

The other problem is that surface mounted caps don't do well in
elevated
reflow temps of ROHS compliant solders.
There's only a few manufacturers claiming compliance (Nichikon being
one).


or amplifier stage within a product. For
instance: A typical (not hugely expensive) CD player will contain between
4
and 8 OP amps. Each OP amp will have two power supply rails. Each rail at
each OP amp will have a capacitor to decouple that rail. Good designers
place the caps VERY close to the OP amps. Caps would typically range from
22uF to 220uF in this application.

Why so much driving a high impedance load? Sounds crazy to me.

**Decent quality audio OP amps can source 50-100mA. Even a venerable 5534
consumes a fair chunk of juice. Electros are necessary in this environment.

If they need that much supply filtering at the op amps they're
doing something wrong in power distribution.

**Possibly.

Go to a multi-layer board with a power plane and ground plane.

**The Japanese very rarely use even double sided boards in audio. They have
always used single sided boards and jumpers. A multilayer board is simply
not even on the radar.

Low inductance supply and low in circuit ESR for your caps.
Far more effective.

**Caps are cheap and very effective.

Trevor Wilson

[Trevor Wilson[_2_]]

"Arny Krueger" wrote in message
. ..


**It seems your memory is faulty. I will explain why so many caps are
used.

* ME amps use no Global NFB.

As I said, some people do crazy things. Not using loop NFB in a power amp
is a genuinely crazy thing. Almost no modern power amps lack loop NFB.

**Wrong. A number of other manufacturers are now emulating what ME did 30
years ago (and still do today). I will readily acknowledge that few mass
market manufacturers choose to do so, however. Additionally, most listeners
prefer the sound of an ME amp which eschews the use to Global NFB. And yes,
ME did some blind tests to establish this. Listener preference for Zero
Global NFB was overwhelming.




Why is a dc block needed in an active crossover?

No, these are decoupling caps, for the power supply. A large number of
electrolytic decoupling caps are not needed - the decoupling caps that
show up in any volume at all are ceramics or film caps, and those
typically have much longer lives than electrolytics.

**Nope. Most domestic products use electros as decoupling elements.

Nonsense. Check the schematics at the Rane site - they are typical.

**I don't need to. Rane are not represented in the domestic market. I
suggest you look to Sony, Panasonic, Sanyo, Marantz, NAD, Rotel, Denon, et
al. These are what most people would regard as domestic equipment
manufacturers. Rane would be what I would refer to as pro and semi pro
equipment manufacturers. Additionally, I suggest you keep in mind that
Stephen's crossover is 20 years old.


Sometimes, these will be bypassed with small value film caps as well.

The bypass caps are often needed. Power supply decoupling for most op amps
is silly and rarely done in audio gear outside of the wasteful high end.

**Wrong. It is VERY common in domestic audio. And trust me when I tell you
this: I KNOW what I am talking about. In fact, I just checked the schematic
of my newly acquired Harman Kardon HD970 CD player. Yep. It uses 47uF
decoupling caps, bypassed with 100nF film caps. It is hardly high end
(though it sure sounds like a high end player). I could go through my filing
cabinet to locate more, but I really cannot be bothered. You'll need to take
my word for it.

Trevor Wilson

[Trevor Wilson[_2_]]

"Arny Krueger" wrote in message
. ..

"MiNe 109" wrote in message
...
In article ,
"Arny Krueger" wrote:

"MiNe 109" wrote in message
...
In article ,
"Arny Krueger" wrote:

Agreed up to the point where a ludicrous number of parts are
involved,
like
150 caps in a simple stereo active crossover.

The Linn probably isn't "a simple stereo active crossover".

Actually, absent a schematic, we don't know one way or the other. Linn
is
well known for hype.

Or you could pop the top and look at it.

Yeah, the one I have right here. NOT!

There's a bunch of parts in there.

Yup, that's an exact number: "a bunch of parts".

There's some complicated phase-correction if it's like the other
Linn
crossover whose
description I quoted.

Unecessarily complicated = bad design. Phase correction even overkilled
doesn't take 100+ caps.

Perhaps that's why Linn developed plug-in cards.

Perhaps not. Most likely: irrelevant.

It also has separate level controls by internal switching.

That need not add any caps at all.

The Rane crossover I've been using as a benchmark obtains its desirable
phase characteristics by means of a sophisticated design that does add a
few
more parts, like maybe 4 op amps, 8 caps and 8 resistors.

I'm sure it works fine.

The point is, it doesn't take 150+ decoupling caps to make a very, very
good crossover.

**Actually, I agree. However, it is 2007, not 1987. Things were different
back then.

Trevor Wilson

[Arny Krueger]

"Trevor Wilson" wrote in message
...

"Arny Krueger" wrote in message
. ..


**It seems your memory is faulty. I will explain why so many caps are
used.

* ME amps use no Global NFB.

As I said, some people do crazy things. Not using loop NFB in a power amp
is a genuinely crazy thing. Almost no modern power amps lack loop NFB.

**Wrong. A number of other manufacturers are now emulating what ME did 30
years ago (and still do today).

Well letsee, there are how many thousand different amplifier manufacturers?
A few nuts doesn't make a fruit cake!

I will readily acknowledge that few mass market manufacturers choose to
do so, however.

Few??? None!!!

Then there is the professional market. Very unlikely there.

Additionally, most listeners prefer the sound of an ME amp which eschews
the use to Global NFB.

Not hardly! Only a miniscule fraction of the billions of music lovers in the
world have ever heard the ME amp.

Trevor, do try to remember that there is a tiny miniscule fraction of world
outside of Australia!

And yes, ME did some blind tests to establish this.

Unlikely that they were properly double blind.

Listener preference for Zero Global NFB was overwhelming.

Only among true believers.


Why is a dc block needed in an active crossover?

No, these are decoupling caps, for the power supply. A large number of
electrolytic decoupling caps are not needed - the decoupling caps that
show up in any volume at all are ceramics or film caps, and those
typically have much longer lives than electrolytics.

**Nope. Most domestic products use electros as decoupling elements.

Nonsense. Check the schematics at the Rane site - they are typical.

**I don't need to.

Right, why confuse yourself with relevant facts, Trevor?

Rane are not represented in the domestic market.

So what? Their products represent good and typical engineering practice.

I suggest you look to Sony, Panasonic, Sanyo, Marantz, NAD, Rotel, Denon,
et al.

Been there, done that.

Case in point, sony's premiere SACD player:

http://www.hifiengine.com/download_c...-1_service.pdf

Check out the op amps in the audio section.

These are what most people would regard as domestic equipment
manufacturers. Rane would be what I would refer to as pro and semi pro
equipment manufacturers. Additionally, I suggest you keep in mind that
Stephen's crossover is 20 years old.

You;re arguing out of both sides of your mouth, Trevor.

Sometimes, these will be bypassed with small value film caps as well.

The bypass caps are often needed. Power supply decoupling for most op
amps is silly and rarely done in audio gear outside of the wasteful high
end.

**Wrong. It is VERY common in domestic audio. And trust me when I tell you
this: I KNOW what I am talking about. In fact, I just checked the
schematic of my newly acquired Harman Kardon HD970 CD player. Yep. It uses
47uF decoupling caps, bypassed with 100nF film caps. It is hardly high end
(though it sure sounds like a high end player). I could go through my
filing cabinet to locate more, but I really cannot be bothered. You'll
need to take my word for it.

Show me the schematic diagram evidence where I can see it for myself as I
have done for you and not your assertions, Trevor.

[Trevor Wilson[_2_]]

"Arny Krueger" wrote in message
. ..

"Trevor Wilson" wrote in message
...

"Arny Krueger" wrote in message
. ..


**It seems your memory is faulty. I will explain why so many caps are
used.

* ME amps use no Global NFB.

As I said, some people do crazy things. Not using loop NFB in a power
amp is a genuinely crazy thing. Almost no modern power amps lack loop
NFB.

**Wrong. A number of other manufacturers are now emulating what ME did 30
years ago (and still do today).

Well letsee, there are how many thousand different amplifier
manufacturers? A few nuts doesn't make a fruit cake!

**Your complete inexperience with ME power amps is duly noted. After you
measure one, get back to me. After you listen to one, get back to me. Until
then, your opinion is worth spit.


I will readily acknowledge that few mass market manufacturers choose to
do so, however.

Few??? None!!!

Then there is the professional market. Very unlikely there.

**Indeed. Price rules.


Additionally, most listeners prefer the sound of an ME amp which eschews
the use to Global NFB.

Not hardly! Only a miniscule fraction of the billions of music lovers in
the world have ever heard the ME amp.

**Their loss.


Trevor, do try to remember that there is a tiny miniscule fraction of
world outside of Australia!

**It ain't tiny.


And yes, ME did some blind tests to establish this.

Unlikely that they were properly double blind.

**Single blind.


Listener preference for Zero Global NFB was overwhelming.

Only among true believers.

**Nope.



Why is a dc block needed in an active crossover?

No, these are decoupling caps, for the power supply. A large number
of electrolytic decoupling caps are not needed - the decoupling caps
that show up in any volume at all are ceramics or film caps, and those
typically have much longer lives than electrolytics.

**Nope. Most domestic products use electros as decoupling elements.

Nonsense. Check the schematics at the Rane site - they are typical.

**I don't need to.

Right, why confuse yourself with relevant facts, Trevor?

**Our discussion is centred around domestic products. You can introduce pro
models if you like. I have little experience with them, so I will not be
discussing them with you.


Rane are not represented in the domestic market.

So what? Their products represent good and typical engineering practice.

**They're not domestic products and I have little experience with them.


I suggest you look to Sony, Panasonic, Sanyo, Marantz, NAD, Rotel,
Denon, et al.

Been there, done that.

**No, you have not. See below.


Case in point, sony's premiere SACD player:

http://www.hifiengine.com/download_c...-1_service.pdf

Check out the op amps in the audio section.

**Done. They sensibly use regulators close to the chips. Common in high end
domestic equipment. Too expensive for cheap domestic equipment however.


These are what most people would regard as domestic equipment
manufacturers. Rane would be what I would refer to as pro and semi pro
equipment manufacturers. Additionally, I suggest you keep in mind that
Stephen's crossover is 20 years old.

You;re arguing out of both sides of your mouth, Trevor.

**Just stating facts. Nothing more.


Sometimes, these will be bypassed with small value film caps as well.

The bypass caps are often needed. Power supply decoupling for most op
amps is silly and rarely done in audio gear outside of the wasteful high
end.

**Wrong. It is VERY common in domestic audio. And trust me when I tell
you this: I KNOW what I am talking about. In fact, I just checked the
schematic of my newly acquired Harman Kardon HD970 CD player. Yep. It
uses 47uF decoupling caps, bypassed with 100nF film caps. It is hardly
high end (though it sure sounds like a high end player). I could go
through my filing cabinet to locate more, but I really cannot be
bothered. You'll need to take my word for it.

Show me the schematic diagram evidence where I can see it for myself as I
have done for you and not your assertions, Trevor.

**Certainly. Proceed to the site you directed me to. Examine the following
brands and models:

Denon:
AVR485
AVR685
AVR1505
AVR1705
PMA700V

Harman Kardon:
HK3250
HK590i

Marantz
CD43
CD53
CD63
CD73
DV7600

NAD
514
5420
5425

Pioneer
A107
A207R
A209
A223
A307R
A400
A407R
A509R
A607R
A616

All use electrolytic caps for decoupling of OP amps.

There are many others, but only owner's manuals and partial schematics are
available on that site.

What strawman will you build now? I can only wonder.

Do yourself a favour: Stop telling me what type of topology is used in
domestic audio equipment. I've been servicing the stuff for 30 years.

Trevor Wilson

[Arny Krueger]

"Trevor Wilson" wrote in message
...

**Certainly. Proceed to the site you directed me to. Examine the following
brands and models:

Denon:
AVR485
AVR685
AVR1505
AVR1705
PMA700V

Lets see if you have done your homework, Trevor or if you are just throwing
the usual crap around.

Here's the box sco

Denon:

http://www.hifiengine.com/manuals.php?man=Denon

AVR685 not listed
AVR505 not listed
AVR1705 not listed
PMA700V not listed

The AVR 485 shows plenty of examples of op amps whose VCC supplies are
bypassed, but not decoupled. Also very many examples of op amps where VCC is
bypassed only with a small film or ceramic capacitor, and not an
electrolytic. Some examples of no proximate bypass at all.

Bottom line Trevor, your Denon list, the first one you provided is too
flawed to bother with the rest. Come back when you've done your homework.

[Trevor Wilson[_2_]]

"Arny Krueger" wrote in message
. ..

"Trevor Wilson" wrote in message
...

**Certainly. Proceed to the site you directed me to. Examine the
following brands and models:

Denon:
AVR485
AVR685
AVR1505
AVR1705
PMA700V

Lets see if you have done your homework, Trevor or if you are just
throwing the usual crap around.

Here's the box sco

Denon:

http://www.hifiengine.com/manuals.php?man=Denon

AVR685 not listed
AVR505 not listed
AVR1705 not listed
PMA700V not listed

The AVR 485 shows plenty of examples of op amps whose VCC supplies are
bypassed, but not decoupled.

**They're decoupled, you clown. The resistance of the PCB tracks and wiring,
in combination with the caps acts as a high pass filter. Get back to me when
you've studied some electronics theory. You supplied one example where a
local regulator was used (the best system, which is usually reserved fro
expensive products), whilst I showed you 25 examples. Stop arguing.

Also very many examples of op amps where VCC is
bypassed only with a small film or ceramic capacitor, and not an
electrolytic. Some examples of no proximate bypass at all.

**Nope. I checked. ALL use electros for decoupling. Every single one. Some
have film caps as well.


Bottom line Trevor, your Denon list, the first one you provided is too
flawed to bother with the rest. Come back when you've done your homework.

**I suggest you ask someone about electronics theory. Every one of the
products listed has decoupling caps on OP amps.

Trevor Wilson

[Trevor Wilson[_2_]]

"ScottW" wrote in message
...

"Trevor Wilson" wrote in message
...

"Arny Krueger" wrote in message
. ..

"Trevor Wilson" wrote in message
...

**Certainly. Proceed to the site you directed me to. Examine the
following brands and models:

Denon:
AVR485
AVR685
AVR1505
AVR1705
PMA700V

Lets see if you have done your homework, Trevor or if you are just
throwing the usual crap around.

Here's the box sco

Denon:

http://www.hifiengine.com/manuals.php?man=Denon

AVR685 not listed
AVR505 not listed
AVR1705 not listed
PMA700V not listed

The AVR 485 shows plenty of examples of op amps whose VCC supplies are
bypassed, but not decoupled.

**They're decoupled, you clown. The resistance of the PCB tracks and
wiring, in combination with the caps acts as a high pass filter. Get back
to me when you've studied some electronics theory. You supplied one
example where a local regulator was used (the best system, which is
usually reserved fro expensive products), whilst I showed you 25
examples. Stop arguing.

Also very many examples of op amps where VCC is
bypassed only with a small film or ceramic capacitor, and not an
electrolytic. Some examples of no proximate bypass at all.

Now I'm confused again....isn't all that power supply stuff
technically decoupling?

**Of course it is. For some reason, Arny wants to argue the point. I have no
idea why. He's wrong.


Bypassing is shunting to ground at the source...not at the
power supply.

**Bypassing is a similar term, but relates to the use of a (say) film cap
across an electro. Or, in the case of a tube amp, when the Cathode is
coupled to ground, through a resistor, which is bypassed with a capacitor.
It gets a little muddy, however.


Here's a reputable app note on high speed digital
circuits which have far greater need .....

http://hsi.web.cern.ch/HSI/s-link/de...c/decouple.pdf

**That particular cite is MUCH better than your earlier one. I concur with
the description.




**Nope. I checked. ALL use electros for decoupling. Every single one.
Some have film caps as well.

Well...I picked one op amp (BTW..I didn't see any obviously in the
audio circuits..only video)..and it was decoupled with a ceramic.

**Duh. What did you expect?

So would you mind specifying a schematic and an op-amp.
PITA to scroll back and forth between schematic and parts list.

******! Find it yourself. I just jumped through hoops for Arny. I'm not
doing it again. OK, ONCE. You get ONE example only. Here goes:

NAD 5000 CD player. Page 34.
IC109, IC110, IC111, IC112, IC113, IC114, IC117.

Happy?

Don't **** me off again. Do your own ****ing legwork. I listed a bunch of
models for you and Arny. Arny can't be bothered searching for proof and
neither, it seems, can you.

All the other models listed have similar topologies.

Trevor Wilson



--
Posted via a free Usenet account from http://www.teranews.com

[Arny Krueger]

"Trevor Wilson" wrote in message
...

"Arny Krueger" wrote in message
. ..

"Trevor Wilson" wrote in message
...

**Certainly. Proceed to the site you directed me to. Examine the
following brands and models:

Denon:
AVR485
AVR685
AVR1505
AVR1705
PMA700V

Lets see if you have done your homework, Trevor or if you are just
throwing the usual crap around.

Here's the box sco

Denon:

http://www.hifiengine.com/manuals.php?man=Denon

AVR685 not listed
AVR505 not listed
AVR1705 not listed
PMA700V not listed

The AVR 485 shows plenty of examples of op amps whose VCC supplies are
bypassed, but not decoupled.

**They're decoupled, you clown.

A few are, most are not. BTW Trevor, your reliance on abuse here rather than
relevant facts to assist your argument basically tells the whole story - you
know that you are fighting a losing battle based on just the facts. By now,
you should know far better than to try to intimidate me! Far better men than
you have tried and failed - the Middiot knows their names very well, and so
should you.

The resistance of the PCB tracks and wiring, in combination with the caps
acts as a high pass filter.

High pass filter? LOL!

Time to hit the books again Trevor, the series resistance of the traces and
the parallel filter caps act like low pass filters. High pass filters don't
pass DC, and DC is what power supplies are all about, no?

Get back to me when you've studied some electronics theory.

If irony killed! It is you who just demonstrated his ignorance of basic
electronics theory!

You supplied one example where a local regulator was used (the best
system, which is usually reserved fro expensive products), whilst I showed
you 25 examples.

Time to study your own references, Trevor. There is at least one example of
a local regulator in the AVR 485.

Stop arguing.

True, I should stop arguing with people who don't even know the difference
between low pass and high pass filters.

Also very many examples of op amps where VCC is
bypassed only with a small film or ceramic capacitor, and not an
electrolytic. Some examples of no proximate bypass at all.

**Nope. I checked. ALL use electros for decoupling. Every single one. Some
have film caps as well.

Nonsense. There's even a case where there are traces to support an
electrolytic, and the schematic notes that it is not installed!

Bottom line Trevor, your Denon list, the first one you provided is too
flawed to bother with the rest. Come back when you've done your homework.

**I suggest you ask someone about electronics theory. Every one of the
products listed has decoupling caps on OP amps.

There are occasional examples of that, but both components we've talked
about power most of their op amps without local decoupling filters.

The logic behind this is that a good op amp has tremendous power supply
rejection, particularly at low frequencies. An op amp that does not have
good power supply rejection, is arguably substandard.


Trevor, please post again when you understand that it is folly to try to try
to apply power through a high pass filter.

[Arny Krueger]

"ScottW" wrote in message
...


Now I'm confused again....isn't all that power supply stuff
technically decoupling?

The distinction between decoupling and bypassing seems to have escaped you,
Scott. You can decouple without bypassing, but it is harder to bypass
without doing at least a little high frequency decoupling.

The purpose of decoupling is to isolate the load from variations in the
source (example: the power supply). The purpose of bypassing is to provide a
source that provides a low source impedance. The process of providing a low
source impedance inherently provides some decoupling.

Many op amps are not stable unless their power supplies provide a low source
impedance, especially at high frequencies. An easy means for providing a
power source with low source impedance is to add bypass capacitors near the
power supply pins of the op amp. Therefore we see a lot of small value caps
clustered around the power supply pins of op amps.

A good op amp will tend to reject variations in its power supply,
particularly at low frequencies where the op amps open-loop gain is
extremely high. Therefore, there are only a limited number of sitautions
where op amp power supplies need to be heavily decoupled.

There are many situations where op amp power supply pins need to be bypassed
at high frequencies. An op amp with high bandwidth is much more likely to
need careful bypassing. In some cases the power supply pins need not be
bypassed to ground at the op amp, but simply effectively connected together
at high frequencies. Therefore we occasionally see cases where just one
relatively small bypass cap is connected between the two power supply pins
of the op amp.

Here's an example of an independent source supporting much of what I've just
written:

http://electronicdesign.com/Articles...leID=1478&pg=2

"The usual arrangement for a pc board is to have a relatively large bypass
capacitor for each supply line at a point close to where dc power enters the
board. Practical values between 1 and 100 µF may be used. As a rule, larger
capacitors are needed in circuits that must deliver large transient currents
into the load. In these applications, the power-supply bypass capacitor
stores the necessary transient energy, which otherwise wouldn't be available
directly from the supply itself due to lead inductance."

"If the pc board holds several op amps, relatively small (0.1-µF)
local-bypass capacitors can be used at each op amp's power-supply pins. A
much larger capacitor, located where the supply line enters the pc board,
can serve as a common bypass for each supply. The effectiveness of a common
bypass depends on several factors, including the length and width of the
wire runs between this bypass and each op amp, the value of the bypass, and
most importantly, the transient current required to drive the load. In many
cases, the power supply will have a very low output impedance, and the pc
wire runs will be very short. Therefore, the power supply itself will be
able to provide the transient energy needed to drive the load. If so, only a
small local bypass is needed at each op amp—just enough to supply
short-duration energy to the op amp."

Bypassing is shunting to ground at the source...not at the
power supply.

I quote my source:

""If the pc board holds several op amps, relatively small (0.1-µF)
local-bypass capacitors can be used at each op amp's power-supply pins."

That's not shunting to ground at the source, it is shunting to ground at the
load.

Here's a reputable app note on high speed digital
circuits which have far greater need .....

http://hsi.web.cern.ch/HSI/s-link/de...c/decouple.pdf

Wrong again Scott. You need to read and understand the titles of articles.
The article is titled:

"Using Decoupling Capacitors"

It is a fine article as far as it goes.

You need to find an article about "Using bypass capacitors".

**Nope. I checked. ALL use electros for decoupling. Every single one.
Some have film caps as well.

Well...I picked one op amp (BTW..I didn't see any obviously in the
audio circuits..only video)..and it was decoupled with a ceramic.

No, it is bypassed with a ceramic. Decoupling and bypassing are two
different things.

The most common symptom of poor bypassing is high frequency oscillation and
ringing. The most common symptom of poor decoupling is low frequency
osciallation and ringing.

So would you mind specifying a schematic and an op-amp.


http://www.hifiengine.com/download_c...-1_service.pdf

Please see page 35, figure 7-13, around IC 171 and 271.

http://www.hifiengine.com/download_c...85_service.pdf

Please see page 62, "Input/Volume Unit", IC 781-784. There are a total of
8 op amps with individual power supply bypassing, but shared decoupling.
In addtion IC 816 on the same page shows an example of an op amp with power
supply bypassing by means of a single relatively small cap connected between
the power supply pins.

PITA to scroll back and forth between schematic and parts list.

It takes a certain lack of intellectual laziness to understand these things.

[Arny Krueger]

"ScottW" wrote in message
oups.com...
On Oct 18, 4:39 am, "Arny Krueger" wrote:
"ScottW" wrote in message

...

Now I'm confused again....isn't all that power supply stuff
technically decoupling?

The distinction between decoupling and bypassing seems to have escaped
you,
Scott. You can decouple without bypassing, but it is harder to bypass
without doing at least a little high frequency decoupling.

The purpose of decoupling is to isolate the load from variations in the
source (example: the power supply). The purpose of bypassing is to provide
a
source that provides a low source impedance. The process of providing a
low
source impedance inherently provides some decoupling.

Many op amps are not stable unless their power supplies provide a low
source
impedance, especially at high frequencies. An easy means for providing a
power source with low source impedance is to add bypass capacitors near
the
power supply pins of the op amp. Therefore we see a lot of small value
caps
clustered around the power supply pins of op amps.

A good op amp will tend to reject variations in its power supply,
particularly at low frequencies where the op amps open-loop gain is
extremely high. Therefore, there are only a limited number of sitautions
where op amp power supplies need to be heavily decoupled.

There are many situations where op amp power supply pins need to be
bypassed
at high frequencies. An op amp with high bandwidth is much more likely to
need careful bypassing. In some cases the power supply pins need not be
bypassed to ground at the op amp, but simply effectively connected
together
at high frequencies. Therefore we occasionally see cases where just one
relatively small bypass cap is connected between the two power supply pins
of the op amp.

Here's an example of an independent source supporting much of what I've
just
written:

http://electronicdesign.com/Articles...leID=1478&pg=2

"The usual arrangement for a pc board is to have a relatively large bypass
capacitor for each supply line at a point close to where dc power enters
the
board. Practical values between 1 and 100 µF may be used. As a rule,
larger
capacitors are needed in circuits that must deliver large transient
currents
into the load. In these applications, the power-supply bypass capacitor
stores the necessary transient energy, which otherwise wouldn't be
available
directly from the supply itself due to lead inductance."

"If the pc board holds several op amps, relatively small (0.1-µF)
local-bypass capacitors can be used at each op amp's power-supply pins. A
much larger capacitor, located where the supply line enters the pc board,
can serve as a common bypass for each supply. The effectiveness of a
common
bypass depends on several factors, including the length and width of the
wire runs between this bypass and each op amp, the value of the bypass,
and
most importantly, the transient current required to drive the load. In
many
cases, the power supply will have a very low output impedance, and the pc
wire runs will be very short. Therefore, the power supply itself will be
able to provide the transient energy needed to drive the load. If so, only
a
small local bypass is needed at each op amp-just enough to supply
short-duration energy to the op amp."

Bypassing is shunting to ground at the source...not at the
power supply.

I quote my source:

""If the pc board holds several op amps, relatively small (0.1-µF)
local-bypass capacitors can be used at each op amp's power-supply pins."

That's not shunting to ground at the source, it is shunting to ground at
the
load.

Here's a reputable app note on high speed digital
circuits which have far greater need .....
http://hsi.web.cern.ch/HSI/s-link/de...c/decouple.pdf

Wrong again Scott. You need to read and understand the titles of articles.
The article is titled:

"Using Decoupling Capacitors"

It is a fine article as far as it goes.

Except the application as described is very much in line
with your article describing bypass caps.

I've further explained the similarities and differences between decoupling
and bypass caps in another post I made after this one.

[Clyde Slick]

On 18 Oct, 14:40, "Arny Krueger" wrote:


I've further explained the similarities and differences between decoupling
and bypass caps in another post I 'made after this one'.

My Krooglish translation is available in another post I made after
this one.
Or maybe its in one I 'will make before this one'!!

[Trevor Wilson[_2_]]

"Arny Krueger" wrote in message
...

"Trevor Wilson" wrote in message
...

"Arny Krueger" wrote in message
. ..

"Trevor Wilson" wrote in message
...

**Certainly. Proceed to the site you directed me to. Examine the
following brands and models:

Denon:
AVR485
AVR685
AVR1505
AVR1705
PMA700V

Lets see if you have done your homework, Trevor or if you are just
throwing the usual crap around.

Here's the box sco

Denon:

http://www.hifiengine.com/manuals.php?man=Denon

AVR685 not listed
AVR505 not listed
AVR1705 not listed
PMA700V not listed

The AVR 485 shows plenty of examples of op amps whose VCC supplies are
bypassed, but not decoupled.

**They're decoupled, you clown.

A few are, most are not.

**THEY ALL ARE. I examined every single one.

BTW Trevor, your reliance on abuse here rather than
relevant facts to assist your argument basically tells the whole story -
you know that you are fighting a losing battle based on just the facts. By
now, you should know far better than to try to intimidate me! Far better
men than you have tried and failed - the Middiot knows their names very
well, and so should you.

The resistance of the PCB tracks and wiring, in combination with the caps
acts as a high pass filter.

High pass filter? LOL!

**Typo, brain fart. Call it what you will. Of course it is a low pass
filter.


Time to hit the books again Trevor, the series resistance of the traces
and the parallel filter caps act like low pass filters. High pass filters
don't pass DC, and DC is what power supplies are all about, no?

Get back to me when you've studied some electronics theory.

If irony killed! It is you who just demonstrated his ignorance of basic
electronics theory!

You supplied one example where a local regulator was used (the best
system, which is usually reserved fro expensive products), whilst I
showed you 25 examples.

Time to study your own references, Trevor. There is at least one example
of a local regulator in the AVR 485.

**IC781, IC782, IC783, IC784 all use decupling caps. Stop being a ****ing
idiot.



Stop arguing.

True, I should stop arguing with people who don't even know the difference
between low pass and high pass filters.

**See above. Stop acting like a moron. I admit my error. I've provided
examples where decoupling caps are used on OP amps.


Also very many examples of op amps where VCC is
bypassed only with a small film or ceramic capacitor, and not an
electrolytic. Some examples of no proximate bypass at all.

**Nope. I checked. ALL use electros for decoupling. Every single one.
Some have film caps as well.

Nonsense. There's even a case where there are traces to support an
electrolytic, and the schematic notes that it is not installed!

**EVERY SINGLE ONE. Unlike you, I examined the schematic of every unit I
mentioned.



Bottom line Trevor, your Denon list, the first one you provided is too
flawed to bother with the rest. Come back when you've done your
homework.

**I suggest you ask someone about electronics theory. Every one of the
products listed has decoupling caps on OP amps.

There are occasional examples of that, but both components we've talked
about power most of their op amps without local decoupling filters.

**EVERY SINGLE ONE. Unlike you, I examined the schematic of every unit I
mentioned.



The logic behind this is that a good op amp has tremendous power supply
rejection, particularly at low frequencies. An op amp that does not have
good power supply rejection, is arguably substandard.

**We are discussing whether decoupling of OP amps is common. We're not
discussing the necessaity for it, or otherwise.



Trevor, please post again when you understand that it is folly to try to
try to apply power through a high pass filter.

**I admit my error. Will you now admit yours?

Trevor Wilson