[Boris[_2_]]

Hi,

If there is a better newsgroup for this question, please let me know.

I want to hook up some old equipment I bought back in 1994. It's an
Onkyo six cd changer, and an Onkyo amp/receiver. It's from the old
Circuit City days. They were mid-range comsumer electronic components
at the time. I can give model numbers if needed.

The amp/receiver will power two sets of speakers, and has two buttons on
the front, A and B to enable one or both sets. The rear of the
amp/receiver has terminals for speakers A and B. Under the row of
terminals, there is a warning:

Caution
Speaker A or B: 4 ohms
Speaker A and B: 8 ohms

I have been using a set of 6 ohm speakers and they work on either A or
B, but I'd like to do things right.

Should I get a set of 4 ohm speakers?
Is the 8 ohm warning only necessary if I have both sets of speakers
enabled, or is it relevant even if I have two sets connected, but only
one enalbled at a time.

I have been to Wikipedia, and googled all of this, but I'd like to hear
from you.

Thanks.

[[email protected]]

Boris: With impedance, go over, but
never under! I don't know any of
the math associated with impedance,
but if your receiver say 4ohms that
is just the minimum you never go
below. You can drive 12ohm speakers
with it, just might not be loud enough
for you.

My receiver can handle 8-16ohm
speakers(It's a 22 year old JVC).
I can run 8ohm and up with it,
never down.

[Boris[_2_]]

wrote in news:44877035-33c1-401c-8801-996bd55bd115
@googlegroups.com:

Boris: With impedance, go over, but
never under! I don't know any of
the math associated with impedance,
but if your receiver say 4ohms that
is just the minimum you never go
below. You can drive 12ohm speakers
with it, just might not be loud enough
for you.

My receiver can handle 8-16ohm
speakers(It's a 22 year old JVC).
I can run 8ohm and up with it,
never down.

Wish I had kept some of my old tube equipment from the mid-70s. But, the
capacitors may be dried out by now.

[Mike Rivers[_2_]]

On 4/28/2017 11:51 AM, Boris wrote:
Wish I had kept some of my old tube equipment from the mid-70s. But, the
capacitors may be dried out by now.

It can be fixed. But tube amplifiers are different from solid state
amplifiers in many ways. A solid state amplifier has a very low output
impedance, which makes the voltage that the speaker sees pretty much the
same for an 8 ohm or a 4 ohm speaker. But for the same applied voltage,
the 4 ohm speaker will draw twice as much current, and that's what makes
the amplifier sweat.

A tube amplifier has an output transformer which has a higher source
impedance, and they make an attempt to match the source (transformer
output) impedance to the load impedance by putting a couple of taps on
the transformer secondary. For a given input signal level, the 4 ohm tap
provides a lower voltage than the 8 ohm tap. You get maximum power
transferred from the amplifier to the speaker when the load and source
impedances are equal.

The other thing about tube amplifiers is that it's not a good idea to
run them with no load on the output transformer. It's not always the
case, but some times the unloaded voltage can get so high that the
transformer will arc between turns of the coil and could be damaged
expensively.

--
"Today's production equipment is IT based and cannot be operated without
a passing knowledge of computing, although it seems that it can be
operated without a passing knowledge of audio" - John Watkinson

Drop by http://mikeriversaudio.wordpress.com now and then

[Phil Allison[_4_]]

Mike Rivers wrote:



But tube amplifiers are different from solid state
amplifiers in many ways. A solid state amplifier has a very low output
impedance, which makes the voltage that the speaker sees pretty much the
same for an 8 ohm or a 4 ohm speaker. But for the same applied voltage,
the 4 ohm speaker will draw twice as much current, and that's what makes
the amplifier sweat.


** Typical SS amps for home hi-fi have output impedances around 0.1 ohms.

The speaker lead adds maybe 0.3 ohms to that - so 0.4 ohms all up.


A tube amplifier has an output transformer which has a higher source
impedance, and they make an attempt to match the source (transformer
output) impedance to the load impedance by putting a couple of taps on
the transformer secondary.


** The output impedance of a good quality tube amp is around 0.5 to 1 ohm when used at the 8 ohms setting.

For a given input signal level, the 4 ohm tap provides a lower voltage
than the 8 ohm tap.

** But with 40% more current available.


You get maximum power
transferred from the amplifier to the speaker when the load and source
impedances are equal.


** More precisely, when the two are *matched* - so an 8ohms load on the 8ohm setting and so on.

However, actual speaker impedance varies widely over the audio range so it is only gonna be "matched" in the mid band - around 200 to 500 Hz.



..... Phil

[geoff]

On 29/04/2017 4:14 a.m., wrote:
Boris: With impedance, go over, but
never under! I don't know any of
the math associated with impedance,
It is fairly simple arithmetic. Google it.

geoff

[[email protected]]

On Friday, April 28, 2017 at 12:14:51 PM UTC-4, wrote:
Boris: With impedance, go over, but
never under! I don't know any of
the math associated with impedance,
but if your receiver say 4ohms that
is just the minimum you never go
below. You can drive 12ohm speakers
with it, just might not be loud enough
for you.

My receiver can handle 8-16ohm
speakers(It's a 22 year old JVC).
I can run 8ohm and up with it,
never down.

My woofer stopped woofing. I blame it on speaker Impotence.

Jack

[geoff]

On 29/04/2017 11:52 PM, wrote:
On Friday, April 28, 2017 at 12:14:51 PM UTC-4, wrote:
Boris: With impedance, go over, but
never under! I don't know any of
the math associated with impedance,
but if your receiver say 4ohms that
is just the minimum you never go
below. You can drive 12ohm speakers
with it, just might not be loud enough
for you.

My receiver can handle 8-16ohm
speakers(It's a 22 year old JVC).
I can run 8ohm and up with it,
never down.

My woofer stopped woofing. I blame it on speaker Impotence.

Jack



If anything I would have expected your tweeter to blow.

geoff

[Mike Rivers[_2_]]

On 4/29/2017 6:09 AM, geoff wrote:
If anything I would have expected your tweeter to blow.

When they're out of phase, they suck.

--
"Today's production equipment is IT based and cannot be operated without
a passing knowledge of computing, although it seems that it can be
operated without a passing knowledge of audio" - John Watkinson

Drop by http://mikeriversaudio.wordpress.com now and then

[[email protected]]

On Saturday, April 29, 2017 at 10:03:03 AM UTC-4, Mike Rivers wrote:
On 4/29/2017 6:09 AM, geoff wrote:
If anything I would have expected your tweeter to blow.

When they're out of phase, they suck.

Watch that use of "phase", you don't want to upset Scott, do you?

Jack :-)


--
"Today's production equipment is IT based and cannot be operated without
a passing knowledge of computing, although it seems that it can be
operated without a passing knowledge of audio" - John Watkinson

Drop by http://mikeriversaudio.wordpress.com now and then

[[email protected]]

On Saturday, April 29, 2017 at 9:10:28 AM UTC-4, geoff wrote:
On 29/04/2017 11:52 PM, wrote:
On Friday, April 28, 2017 at 12:14:51 PM UTC-4, wrote:
Boris: With impedance, go over, but
never under! I don't know any of
the math associated with impedance,
but if your receiver say 4ohms that
is just the minimum you never go
below. You can drive 12ohm speakers
with it, just might not be loud enough
for you.

My receiver can handle 8-16ohm
speakers(It's a 22 year old JVC).
I can run 8ohm and up with it,
never down.

My woofer stopped woofing. I blame it on speaker Impotence.

Jack



If anything I would have expected your tweeter to blow.

Excuse me, but 3kHz is Midrange!!

I'm lovin' my Sony headphones, they allow me to hear tape [hiss] noise, gives me a better idea of limitations.

Like, wow, The Partridge Family, I never knew there as a tambourine, but now I hear one. Time to embarrass Sony Music once again!!

Jack

geoff

[Don Pearce[_3_]]

On Sat, 29 Apr 2017 10:16:56 -0700 (PDT), wrote:

Excuse me, but 3kHz is Midrange!!

Not when you're 67 it isn't

d

---
This email has been checked for viruses by Avast antivirus software.
https://www.avast.com/antivirus

[[email protected]]

Went to computer show. Found new JVC Speakers, like $10. Complete with bass & treble controls. DC supply is massive. Bottom line, they are nice. Wish I bought a dozen!

Jack

[Scott Dorsey]

Boris wrote:

If there is a better newsgroup for this question, please let me know.

That would be rec.audio.tech.

The amp/receiver will power two sets of speakers, and has two buttons on
the front, A and B to enable one or both sets. The rear of the
amp/receiver has terminals for speakers A and B. Under the row of
terminals, there is a warning:

Caution
Speaker A or B: 4 ohms
Speaker A and B: 8 ohms

These are minimum ratings. If you use just one set of speakers, 4 ohm
speakers are fine. If you use both at the same time, you need 8 ohm
or higher.

I have been using a set of 6 ohm speakers and they work on either A or
B, but I'd like to do things right.

That's fine, just don't use two sets of 6 ohm speakers.

Should I get a set of 4 ohm speakers?

Buy speakers that sound good, don't worry about the impedance. Worry about
how they sound.
--scott


--
"C'est un Nagra. C'est suisse, et tres, tres precis."

[Boris[_2_]]

(Scott Dorsey) wrote in
news
Boris wrote:

If there is a better newsgroup for this question, please let me know.

That would be rec.audio.tech.

The amp/receiver will power two sets of speakers, and has two buttons
on the front, A and B to enable one or both sets. The rear of the
amp/receiver has terminals for speakers A and B. Under the row of
terminals, there is a warning:

Caution
Speaker A or B: 4 ohms
Speaker A and B: 8 ohms

These are minimum ratings. If you use just one set of speakers, 4 ohm
speakers are fine. If you use both at the same time, you need 8 ohm
or higher.

When you say 'at the same time', could I have two sets of 4 ohm speakers
connected, but only play through one set,say set A enabled, at a time?
Or, is just having two sets of 4 ohm speakers connected at the same
time, even if only one set is playing, incorrect?

I have been using a set of 6 ohm speakers and they work on either A or
B, but I'd like to do things right.

That's fine, just don't use two sets of 6 ohm speakers.

Should I get a set of 4 ohm speakers?

Buy speakers that sound good, don't worry about the impedance. Worry
about how they sound.

Totally agree.

--scott

[Scott Dorsey]

Boris wrote:
(Scott Dorsey) wrote in

These are minimum ratings. If you use just one set of speakers, 4 ohm
speakers are fine. If you use both at the same time, you need 8 ohm
or higher.

When you say 'at the same time', could I have two sets of 4 ohm speakers
connected, but only play through one set,say set A enabled, at a time?
Or, is just having two sets of 4 ohm speakers connected at the same
time, even if only one set is playing, incorrect?

If only one set is selected, it's fine. The problem is that sooner or
later, if the buttons allow both sets to be selected, someone will do that.
You can put a big sign on it saying not to do that, but someday it will
happen and then the output stage will fail.
--scott


--
"C'est un Nagra. C'est suisse, et tres, tres precis."

[geoff]

On 29/04/2017 7:14 a.m., Boris wrote:
When you say 'at the same time', could I have two sets of 4 ohm speakers
connected, but only play through one set,say set A enabled, at a time?

Yes, but sounds like a recipe for disaster as a 2 ohm load may be momentarily applied at the wrong moment ...

geoff

[[email protected]]

Scott Dorsey wrote:

"That's fine, just don't use two sets of 6 ohm speakers"

Why not? They're above the minimum
stated on the back of his receiver.



"Buy speakers that sound good, don't worry about the impedance. Â*Worry about
how they sound"

Typical 'engineer' statement. Fine:

Remove all impedance specs from
the backs of speakers, receivers, and
amplifiers. While we're at it, remove
signal presence and OL single LED
indicators and all the meters from
DAWs and mixing consoles.

Remove the specifications page
from the website and from the operators
manuals. It doesn't matter right?
Whether to run balanced or unbalanced
lines, whether this component is over
heating, that one is distorting, or the
other one is clipping. As long as it
"sounds good" "Use your ears"!!!

Ave Maria purissmo...

[geoff]

On 29/04/2017 9:20 a.m., wrote:
Scott Dorsey wrote:

"That's fine, just don't use two sets of 6 ohm speakers"

Why not? They're above the minimum
stated on the back of his receiver.



"Buy speakers that sound good, don't worry about the impedance. Worry about
how they sound"

Typical 'engineer' statement. Fine:

Remove all impedance specs from
the backs of speakers, receivers, and
amplifiers. While we're at it, remove
signal presence and OL single LED
indicators and all the meters from
DAWs and mixing consoles.

Remove the specifications page
from the website and from the operators
manuals. It doesn't matter right?
Whether to run balanced or unbalanced
lines, whether this component is over
heating, that one is distorting, or the
other one is clipping. As long as it
"sounds good" "Use your ears"!!!

Ave Maria purissmo...

I hope you were joking (not always apparent).

Sounds great, still sounds great, oh it's stopped completely. Too late.

geoff

[[email protected]]

geoff wrote: "
I hope you were joking (not always apparent).

Sounds great, still sounds great, oh it's stopped completely. Too late.

geoff "


I was stone-cold serious geoff.

Scott Dorsey and Ian Shepard are
two of the biggest "use your ears"/
"whatever sounds best" advocates
in and out of rec.audio.pro. So I
meant it: Why label the backs of
amps and speakers with impedance
ranges, have meters on equipment,
or have specification sheets, since
specs "don't matter" according to
those two? Take altimeters out of
planes and speedometers out of
cars & trucks while we're at it -
just fly as high as feels comfortable,
and go with the flow in traffic!

[geoff]

On 29/04/2017 2:05 p.m., wrote:
geoff wrote: "
I hope you were joking (not always apparent).

Sounds great, still sounds great, oh it's stopped completely. Too late.

geoff "


I was stone-cold serious geoff.

Scott Dorsey and Ian Shepard are
two of the biggest "use your ears"/
"whatever sounds best" advocates
in and out of rec.audio.pro. So I
meant it: Why label the backs of
amps and speakers with impedance
ranges, have meters on equipment,
or have specification sheets, since
specs "don't matter" according to
those two? Take altimeters out of
planes and speedometers out of
cars & trucks while we're at it -
just fly as high as feels comfortable,
and go with the flow in traffic!

He was referring to subtle aspects of sound quality. Not to whether or
not you have blown up your amp.

geoff

[Scott Dorsey]

wrote:
Scott Dorsey and Ian Shepard are
two of the biggest "use your ears"/
"whatever sounds best" advocates
in and out of rec.audio.pro. So I
meant it: Why label the backs of
amps and speakers with impedance
ranges, have meters on equipment,
or have specification sheets, since
specs "don't matter" according to
those two? Take altimeters out of
planes and speedometers out of
cars & trucks while we're at it -
just fly as high as feels comfortable,
and go with the flow in traffic!

If your specification sheet consists only of useless information
like a scalar impedance number (which really bears little connection
to the actual speaker impedance plot), a frequency range without
tolerances (which is utterly meaningless) and speaker power ratings that
are made up by someone in the marketing department, then by all means we
should definitely not have specification sheets.

Because these are not actual specifications, they are not actual measurements,
they are more misleading than helpful.

Making decisions based on such information is not going to do you any good,
it will only give you a false sense of being informed when you are not.
--scott


--
"C'est un Nagra. C'est suisse, et tres, tres precis."

[[email protected]]

Scott Dorsey wrote:

"That's fine, just don't use two sets of 6 ohm speakers"

Why not? They're above the minimum
stated on the back of his receiver.



"Buy speakers that sound good, don't worry about the impedance. Â*Worry about
how they sound"

Typical 'engineer' statement. Fine:

Remove all impedance specs from
the backs of speakers, receivers, and
amplifiers. While we're at it, remove
signal presence and OL single LED
indicators and all the meters from
DAWs and mixing consoles.

Remove the specifications page
from the website and from the operators
manuals. It doesn't matter right?
Whether to run balanced or unbalanced
lines, whether this component is over
heating, that one is distorting, or the
other one is clipping. As long as it
"sounds good" "Use your ears"!!!

Ave Maria purissmo...

[None]

thekmahhhhh @ dum****.retard.doh wrote in message
...
Scott Dorsey wrote:
Remove all impedance specs from
the backs of speakers, receivers, and
amplifiers. While we're at it, remove
signal presence and OL single LED
indicators and all the meters from
DAWs and mixing consoles.

Remove the specifications page
from the website and from the operators
manuals

And remove your retarded skull from your rectum. Your colon cancer has
spread to your tiny little brain, due to direct physical contact. In
your case, since you dont give a **** what anything actually sounds
like, and your shoe-size IQ won't allow you to use anything resembling
reason, you should just buy whatever the **** appeals to your
grape-sized intellect, and keep a bucket of gasoline handy to douse
the amplifier when it gets to hot.

You should probably just re-wire your entire home electrical system,
guided by random eejits on the net. When the code requires you to do
the arithmetic, just connect your toaster to the bus bars with jumper
cables. LKHSD, BDQNAPDJBF. FCKWAFA!

[[email protected]]

Scott Dorsey wrote:

"That's fine, just don't use two sets of 6 ohm speakers"

Why not? They're above the minimum
stated on the back of his receiver.



"Buy speakers that sound good, don't worry about the impedance. Â*Worry about
how they sound"

Typical 'engineer' statement. Fine:

Remove all impedance specs from
the backs of speakers, receivers, and
amplifiers. While we're at it, remove
signal presence and OL single LED
indicators and all the meters from
DAWs and mixing consoles.

Remove the specifications page
from the website and from the operators
manuals. It doesn't matter right?
Whether to run balanced or unbalanced
lines, whether this component is over
heating, that one is distorting, or the
other one is clipping. As long as it
"sounds good" "Use your ears"!!!

Ave Maria purissmo...

[geoff]

On 29/04/2017 9:59 a.m., wrote:
Scott Dorsey wrote:

"That's fine, just don't use two sets of 6 ohm speakers"

Why not? They're above the minimum
stated on the back of his receiver.



"Buy speakers that sound good, don't worry about the impedance. Worry about
how they sound"

Typical 'engineer' statement. Fine:

Remove all impedance specs from
the backs of speakers, receivers, and
amplifiers. While we're at it, remove
signal presence and OL single LED
indicators and all the meters from
DAWs and mixing consoles.

Remove the specifications page
from the website and from the operators
manuals. It doesn't matter right?
Whether to run balanced or unbalanced
lines, whether this component is over
heating, that one is distorting, or the
other one is clipping. As long as it
"sounds good" "Use your ears"!!!

Ave Maria purissmo...

It was stupid once. Thrice is stupider.

geoff

[Ron C[_2_]]

On 4/28/2017 9:38 PM, geoff wrote:
On 29/04/2017 9:59 a.m., wrote:
Scott Dorsey wrote:

"That's fine, just don't use two sets of 6 ohm speakers"

Why not? They're above the minimum
stated on the back of his receiver.



"Buy speakers that sound good, don't worry about the impedance. Worry
about
how they sound"

Typical 'engineer' statement. Fine:

Remove all impedance specs from
the backs of speakers, receivers, and
amplifiers. While we're at it, remove
signal presence and OL single LED
indicators and all the meters from
DAWs and mixing consoles.

Remove the specifications page
from the website and from the operators
manuals. It doesn't matter right?
Whether to run balanced or unbalanced
lines, whether this component is over
heating, that one is distorting, or the
other one is clipping. As long as it
"sounds good" "Use your ears"!!!

Ave Maria purissmo...

It was stupid once. Thrice is stupider.

geoff

I'll give K-Man a tiny bit of credit for having learned
a few things since he started posting here.

However, it seems the world of difference between
consumer gear "specs" and pro gear specs.
[The quality of /prosumer/ specs are a total toss-up.]

When Scott and others here say "use your ears" there
are a lot of unstated assumptions that pro and semi-pro
understand with out the need for a detailed /caveat/ list.

==
Later...
Ron Capik
--

[[email protected]]

Ron Capik wrote: "I'll give K-Man a tiny bit of credit for having learned
a few things since he started posting here. "

Thanks!



"When Scott and others here say "use your ears" there
are a lot of unstated assumptions that pro and semi-pro
understand with out the need for a detailed /caveat/ list."

Well, we all know about ASSuming, and
one would have to BE one by stating
that documentation and metering are
not important. To them I say: Both
meters and ears matter!

[[email protected]]

On Friday, April 28, 2017 at 10:40:04 PM UTC-4, Ron C wrote:
On 4/28/2017 9:38 PM, geoff wrote:
On 29/04/2017 9:59 a.m., wrote:
Scott Dorsey wrote:

"That's fine, just don't use two sets of 6 ohm speakers"

Why not? They're above the minimum
stated on the back of his receiver.



"Buy speakers that sound good, don't worry about the impedance. Worry
about
how they sound"

Typical 'engineer' statement. Fine:

Remove all impedance specs from
the backs of speakers, receivers, and
amplifiers. While we're at it, remove
signal presence and OL single LED
indicators and all the meters from
DAWs and mixing consoles.

Remove the specifications page
from the website and from the operators
manuals. It doesn't matter right?
Whether to run balanced or unbalanced
lines, whether this component is over
heating, that one is distorting, or the
other one is clipping. As long as it
"sounds good" "Use your ears"!!!

Ave Maria purissmo...

It was stupid once. Thrice is stupider.

geoff

I'll give K-Man a tiny bit of credit for having learned
a few things since he started posting here.

However, it seems the world of difference between
consumer gear "specs" and pro gear specs.
[The quality of /prosumer/ specs are a total toss-up.]



Feel, so called, audiophiles depend 100% on equipment, hoping it will make the music they like sound better!! You see people making money with HD files, HD CD, HD this and that, just like Pono stuff, but so many don't know HQ audio if it bit them in the arse!

Jack



When Scott and others here say "use your ears" there
are a lot of unstated assumptions that pro and semi-pro
understand with out the need for a detailed /caveat/ list.

==
Later...
Ron Capik
--

[Mike Rivers[_2_]]

On 4/28/2017 8:57 AM, Boris wrote:
The amp/receiver will power two sets of speakers, and has two buttons on
the front, A and B to enable one or both sets. The rear of the
amp/receiver has terminals for speakers A and B. Under the row of
terminals, there is a warning:

Caution
Speaker A or B: 4 ohms
Speaker A and B: 8 ohms

I have been using a set of 6 ohm speakers and they work on either A or
B, but I'd like to do things right.

Should I get a set of 4 ohm speakers?

Nope, not unless you get some that will be a significant improvement
over what you already have, for reasons other than impedance.

What they're trying to tell you here is that the amplifier is perfectly
comfortable driving a 4 ohm load (which would be two 8 ohm speakers in
parallel) but it wouldn't be happy driving a 2 ohm load (two 4 ohm
speakers in parallel).

Speaker impedance is mostly nominal anyway, and can vary a great amount
with frequency. Also, speaker efficiency also varies a lot. This means
that for an average power of 1 watt going to the speaker (whatever
voltage it takes for a given impedance) not all speakers will play at
the same loudness.

Is the 8 ohm warning only necessary if I have both sets of speakers
enabled, or is it relevant even if I have two sets connected, but only
one enalbled at a time.

If you have two sets of speakers connected and use only one set at a
time, that's the same as having only one set of speakers connected. So
you could connect two sets of 4 ohm speakers and use them one at a time
with no worries. In truth, you could probably use them both together and
not cause any trouble unless you're running them very loud.

--
"Today's production equipment is IT based and cannot be operated without
a passing knowledge of computing, although it seems that it can be
operated without a passing knowledge of audio" - John Watkinson

Drop by http://mikeriversaudio.wordpress.com now and then

[geoff]

On 29/04/2017 3:57 a.m., Boris wrote:
Hi,

If there is a better newsgroup for this question, please let me know.

I want to hook up some old equipment I bought back in 1994. It's an
Onkyo six cd changer, and an Onkyo amp/receiver. It's from the old
Circuit City days. They were mid-range comsumer electronic components
at the time. I can give model numbers if needed.

The amp/receiver will power two sets of speakers, and has two buttons on
the front, A and B to enable one or both sets. The rear of the
amp/receiver has terminals for speakers A and B. Under the row of
terminals, there is a warning:

Caution
Speaker A or B: 4 ohms
Speaker A and B: 8 ohms

I have been using a set of 6 ohm speakers and they work on either A or
B, but I'd like to do things right.

Should I get a set of 4 ohm speakers?
Is the 8 ohm warning only necessary if I have both sets of speakers
enabled, or is it relevant even if I have two sets connected, but only
one enalbled at a time.

I have been to Wikipedia, and googled all of this, but I'd like to hear
from you.

Thanks.

Should be fine for one pair of 6 ohm speakers on A or B.

Looks like the limiting factor is 4 ohm minimum impedance, which would
be 3 if you had two pairs attached at the same time, as it could seem to
be one stereo amp with simple switching on the output, or a 4-channel
amp with a power-supply limitation to driving a total total of 2 x 4 ohms.


geoff

[Phil Allison[_4_]]

Boris wrote:


Is the 8 ohm warning only necessary if I have both sets of speakers
enabled, or is it relevant even if I have two sets connected, but only
one enalbled at a time.


** The warning is about using a load that has an impedance less than 4 ohms - cos the makers figure the amp is at it's safe limit with that number.

But makers also know that overheating will not occur unless the amp is played to its output power limit - as it might be during a party.

You need to keep both facts in mind.

..... Phil

[PStamler]

So that B&W hits a minimum impedance of 3 ohms at around 650Hz. That could be a nasty load to drive.

QUAD ESL-63s are famous for being easy loads to drive, unlike the original QUAD ESL, now dubbed the ESL-57, which was essentially a shunt capacitor. As Scott said, it could provoke oscillation in marginally-stable amplifiers.

To go back to the original poster's question: what you need to understand is that impedances in parallel add *down*, not up. The formula is, for two speakers A & B hooked up in parallel:

1/total = 1/A + 1/B

So let's say speakers A & B are 4 ohms and 6 ohms respectively, 1/A = 0.25, 1/6 = 0.166..., . Add those two fractions, and you get 0.41666... Since 1/total equals that, the total will be 1/0.416666..., or 2.4 ohms. which can cause problems on most power amplifiers.

What that somewhat mysterious graphic on the back of his amplifier means is that if he connects only one speaker it can have a nominal impedance as low as 4 ohms (it can be higher, but 4 ohms is a minimum), but if he connects more than one speaker, each has to be a minimum of 8 ohms (two of those in parallel work out to 4 ohms total). Which implies a not-super-robust power amplifier in his receiver, which is par for the course for consumer gear.

There's a lot more complexity than that (which other posters have alluded to), but that's the basic story.

Peace,
Paul

[Phil Allison[_4_]]

PStamler wrote:



QUAD ESL-63s are famous for being easy loads to drive, unlike the
original QUAD ESL, now dubbed the ESL-57, which was essentially a shunt
capacitor.

** Hardly.

The impedance is 14 ohms out to 5kHz then drops to 1.7 ohms at 17kHz rising sharply above. It's actually a very easy load to drive.

The issue is with large sub-sonic frequencies that overdrive and saturate the input transformer. This will instantly fry output transistors in an unprotected amplifier.

Used to be a problem in the vinyl era, not so much now.


...... Phil

[[email protected]]

The issue is with large sub-sonic frequencies that overdrive and saturate the input transformer. This will instantly fry output transistors in an unprotected amplifier.

Used to be a problem in the vinyl era, not so much now.


..... Phil

input transformer?

the speakers had a transformer?

m

[Scott Dorsey]

wrote:

The issue is with large sub-sonic frequencies that overdrive and saturate the input transformer. This will instantly fry output transistors in an unprotected amplifier.

Used to be a problem in the vinyl era, not so much now.

input transformer?

the speakers had a transformer?

Yes, step-up transformer.... the electrostatic element is a big capacitor
whose plates move back and forth with charge because they attract and repel.
In order to do this on a large scale you need comparatively high voltages,
so there's a step up transformer and a bias supply inside the box.

(The transformer reflects the capacitive load back to the amplifier, which
sees the element shunt capacitance divided by the transformer turns ratio,
and that's why these speakers are difficult to drive for typical hi-fi amps.)

Now.... if you're thinking about this at all, you'll think "why do I have
a step-down transformer on my tube amplifier and then a step-up transformer
in the amp? Why not just use a high voltage transmitting tube as a final
and drive the electrostat directly off the plate?" A number of people have
had that idea over the years, most notably Acoustat, and they found that
overload protection was a difficult issue.
--scott

--
"C'est un Nagra. C'est suisse, et tres, tres precis."

[[email protected]]

In the case of consumer speakers,
when the impedance is labeled on
the back, is it the lowest measurement,
or an average? Does such procedure
vary by mfg?

[Phil Allison[_4_]]

Scott Dorsey wrote:



input transformer?

the speakers had a transformer?

Yes, step-up transformer.... the electrostatic element is a big capacitor
whose plates move back and forth with charge because they attract and repel.



** Well, that's the popular misconception.

The driven plates of an ESL are always *fixed* in place.

The high DC voltage is applied to the plastic diaphragm which crucially is coated in a HIGH resistance material.

The presence of the moving diaphragm acts as a load on the capacitor formed by the fixed drive plates - making it very lossy.

The famous Quad ESL63 ( and later marks) uses a multi section delay line operating at high voltage which has the additional effect of ELIMINATING the capacitance effect at high frequencies seen with other designs.

It presents a near resistive load over the mid and high frequency ranges.

http://user.tninet.se/~vhw129w/mt_au..._impedance.jpg


.... Phil

[PStamler]

Back in the 1970s, didn't the Acouetical Manufacturing Company (makers of Q..U.A.D. speakers) publish an equivalent circuit for the speaker we know as the ESL-57? I remember seeing it in one of the British hi-fi mags; it included a shunt 2µF capacitor with nothing in series with it.

Peace,
Paul

[Phil Allison[_4_]]

PStamler wrote:


Back in the 1970s, didn't the Acouetical Manufacturing Company
(makers of Q.U.A.D. speakers) publish an equivalent circuit for
the speaker we know as the ESL-57?


** Don't think so.

I remember seeing it in one of the British hi-fi mags;


** Very reliable - not.


it included a shunt 2µF capacitor with nothing in series with it.


** As the speaker's impedance rises above 20Khz, that is dead wrong.


A Quad ESL57 has a impedance of 6 ohms at 20Hz, rising smoothly to its maximum of 30ohms resistive at 100Hz then falling gradually to 12 ohms at 5kHz. Above 5Khz it falls smoothly to 2ohms resistive at 18kHz - then rises steadily beyond that.

Connecting a 2uF cap directly across the output of an amplifier is an absurd test.


..... Phil