Mr.T wrote:
"Don Pearce" wrote in message
...
I should perhaps add that while in itself it has no great
significance, it does offer some insight into the internal working of
the amplifier and the general quality of the design.
But not in any kind of linear relationship, i.e. a bigger 'damping
factor' doesn't imply a better amplifier, once you get past 50 or so.
No, but a SS amp with a really poor output impedance rings all sorts
of alarm bells for reasons unconnected with impedance.

It usually means it's got minimal feedback. That may ring alarm bells in a
cheap amp I suppose.

MrT.


It will ring even louder for an expensive amp! It's just the sort of
stuff that audiophools fall for. Minimal or no feedback, high
distortion, high output impedance, of course it will sound different in
a dealer's demo, and as in audiophool parlance difference = better, it
will sell, and another sucker is taken in.

S.

"Don Pearce" wrote in message
...
I should perhaps add that while in itself it has no great
significance, it does offer some insight into the internal working of
the amplifier and the general quality of the design.

But not in any kind of linear relationship, i.e. a bigger 'damping
factor' doesn't imply a better amplifier, once you get past 50 or so.

No, but a SS amp with a really poor output impedance rings all sorts
of alarm bells for reasons unconnected with impedance.

It usually means it's got minimal feedback. That may ring alarm bells in
a
cheap amp I suppose.

Which in its turn implies that there is very little internal open loop
gain, which in turn could imply that the voltage amplifier is rather
lightly supplied with dominant pole compensation in order to prop up
the top end. The result of all of this would be marginal stability at
the top end.

Not sure that price has a lot to do with it, as this kind of thing has
been seen in quite expensive amps - some even seem to consider it a
"feature".

Unfortunately very true. The inverse is also true, there have been many
dubious attempts at trying to make crap amps work by the addition of copious
amounts of negative feedback. Quality is simply not measured by the damping
factor.

MrT.

"Serge Auckland" wrote in message
...
It will ring even louder for an expensive amp! It's just the sort of
stuff that audiophools fall for. Minimal or no feedback, high
distortion, high output impedance, of course it will sound different in
a dealer's demo, and as in audiophool parlance difference = better, it
will sell, and another sucker is taken in.

Just the same as suckers who think large amounts of negative feedback always
makes an amp great, I suppose.
If I'm comparing amp specs, damping factor is the last thing on my list.

MrT.

Pooh Bear wrote:
TimPerry wrote:

Pooh Bear wrote:
TimPerry wrote:

Pooh Bear wrote:
TimPerry wrote:

GoPack wrote:
I have a house heavily wired with Video Coax cable and Cat5
network cables. Can either of these be adapted to use as
speaker cables? If so, how?

Thanks

SM

cat 5 is becoming more popular for use in fixed audio installs, i
guess do to low price and the availability of telephone and
computer guys familiar with it.

see http://www.studiohub.com/ for running audio and stuff
through cat 5.

for small bookshelf type speakers you could strip back all 8
conductors .. then twist blue/white and white/blue together and
repeat for each color pair.

that gives you 4 conductors. select a color for left + another
for left - and so on.

The wire's cross-sectional area is far too small to be any good as
speaker cable.

Graham

even a single strand of 24GA isnt that much different in size then
the wire that comes with most small home stereo systems.

Not true actually but in any event hardly the point.

Graham

there is a wonderful system known as 70 volt (somtimes 100 volt or
an older type 25 volt audio.

this involve step up and step down transformers at each end of the
wire. the advantage is you can parallel all the wires in the house
together and put speakers in every room of the house all on the same
audio amplifier. AND it eliminates most or all the issues that
Graham is concerned about.

'course if wont be true hifi to a purest... the the PO only said
"speakers"....

70 or 100 volt lines are shockingly poor quality on account of the
transformers.

Graham

i think the 'poor quality' is more do to the $3 speakers that are often used
plus cheapo paging mics.

Mr.T wrote:
"Walt" wrote

So you think a long length of unshielded wire is OK for line level
signals?

Absolutely, if the signals are balanced. I've run balanced signals
several thousand feet on unshielded cable with no problem.

What HiFi equipment is that? (nobody mentioned PA gear or balanced signals)

IMO going balanced in a HiFi system is unlikely to be cost effective
solution.

Adding balancing circuitry to consumer hi fi gear is probably cheaper
than pulling new wires. If the budget is tight, you can often get away
with just balancing the input while leaving the output single ended.
(common mode rejection works even if there is no signal present on one
of the conductors) Figure $100 or so to do just the inupt end, $200 to
balance the signal at both ends.

Or if you use powered speakers that have a balanced input, it might not
cost anything extra at all. Well, beyond the cost of the powered speakers.

Even for pro audio use the current trend is going digital.

Agree completely. Which is one of the reasons cat5 is being installed
for analog use - just because the signal is analog today doesn't mean
that it won't be upgraded to digital in the near future. Might as well
install cables that can handle both.

//Walt

Mr.T wrote:
"Walt" wrote

If you try to use one cat 5 cable to run stereo speaker signals, you're
looking at 21 gauge at best. Can you say "highly sub-optimal"?

Can you say quite good enough for background muzak.

No, I can't say that. Allow me to repeat myself:

"neither wire appropriate for speaker level signals. It might be
passible for very low level background level, but not for any kind of
foreground application."

//Walt

"Mr.T" wrote:

IMO going balanced in a HiFi system is unlikely to be cost effective
solution.

A balanced input costs very, very litle more than an unbalanced one actually and
the outputs themselves don't actually need to be balanced to get the advantage
that a balanced input gives you.

Even for pro audio use the current trend is going digital.

And AES3 digital audio is balanced.

Graham

TimPerry wrote:

Pooh Bear wrote:

70 or 100 volt lines are shockingly poor quality on account of the
transformers.

Graham

i think the 'poor quality' is more do to the $3 speakers that are often used
plus cheapo paging mics.

In equal measure I reckon actually.

Graham

Pooh Bear wrote:
TimPerry wrote:
Pooh Bear wrote:

70 or 100 volt lines are shockingly poor quality on account of the
transformers.

i think the 'poor quality' is more do to the $3 speakers that are often used
plus cheapo paging mics.

In equal measure I reckon actually.

These things feed on themselves -

"No need to use a U87 given those crap ass speakers."
"No need to use decent speakers with those nasty paging mics."
"Why bother with decent anything since it's all going through those
awful transformers."

It lends new meaning to the term "feedback cycle".

//Walt

Walt wrote:

Pooh Bear wrote:
TimPerry wrote:
Pooh Bear wrote:

70 or 100 volt lines are shockingly poor quality on account of the
transformers.

i think the 'poor quality' is more do to the $3 speakers that are often used
plus cheapo paging mics.

In equal measure I reckon actually.

These things feed on themselves -

"No need to use a U87 given those crap ass speakers."
"No need to use decent speakers with those nasty paging mics."
"Why bother with decent anything since it's all going through those
awful transformers."

It lends new meaning to the term "feedback cycle".

Given the typical application of 70 / 100 V line ( paging - PA in the sense of
railroad terminals and airports etc ) it's no great surprise that quality isn't a
great consideration.

Graham

On Wed, 7 Jun 2006 22:21:07 +1000, "Mr.T" MrT@home wrote:

"Stewart Pinkerton" wrote in message
news
Bull****. Variations of 3 to 20 ohms are quite common in modern
speakers, which will give a highly audible 5dB variation in level with
a 3 ohm cable. As someone else already noted, you don't want much more
than 100 milliohms in the loop. That's about ten or fifteen feet of
the kind of cheap speaker wire they give away when you buy speakers.

That's going from one extreme to the other! To say that 3 ohms (quite
high
for just about any house run) *may* give a couple of dB variation and
thus
be audible, is one thing, but to claim you HAVE to go as low as 100
milliohm
is stretching your credibility.

Not really. 3 ohms would be about right for what he was considering,
and a 5dB variation is *highly* audible.

Agreed, but are 1dB variations? Name one speaker that can do better than
that?

I'm talking about variations from the speaker's existing response, not
absolute flatness per se. And yes, a 1dB change is audible.

(You don't need 100 millohms to get less than 1dB)

Depends on the speaker. OTOH, 100 milliohms isn't hard to achieve for
very little cost in most systems, so why not just take cable impedance
right out of the equation?

100 milliohms is not hard to
achieve with decent wiring, and pretty much guarantees no problems
unless you have *really* bizarre spekares, which is why it's a
reasonable benchmark. Y

Says who? With most speakers it is simply overkill. Sure it is cheap easy
overkill which I also do myself, but to claim it is necessary, is not true
in the *VAST* majority of cases.

I didn't say it was necessary, I said it was a reasonable and easily
achieved benchmark. Get over yourself, BA.

ou could have 8 ohms of wire without problems
with the *constant* 4-ohm impedance of the KEF 104aBs I used to own,
due to their cunningly contrived constant impedance - but they would
have sounded like sh1t compared to modern speakers.

You really believe modern "white van" speakers are better than the KEFs?
Such unqualified statements are what caused this argument in the first
place.

Modern mainstream speakers of equivalent price is the obvious context.
Stop whining, just because you lost the argument.

Zero ohms is lovely and all that, but you're not likely to pick much less
than one ohm without an A/B direct comparison, in the *majority* of
cases.

And less than one ohm is not hard to achieve.

Indeed, it's a piece of **** in most installations. I wouldn't even
*think* of having more than 0.1ohm without good reason

Me either, but only because it's cheap and easy to do. I'm not silly enough
to claim it is imperitive.

Neither is anyone else.

Also I doubt he has perfect
speakers to start with, extra resistance will even improve some of them!

Sheer conjecture.

Exactly, just like your statements.

Nope, you're just whining because your knee-jerk bull**** was
deconstructed.
--

Stewart Pinkerton | Music is Art - Audio is Engineering

"Walt" wrote in message
...
If you try to use one cat 5 cable to run stereo speaker signals, you're
looking at 21 gauge at best. Can you say "highly sub-optimal"?

Can you say quite good enough for background muzak.

No, I can't say that.
It might be passible for very low level background level,

You just did say that then, only in slightly different words.

MrT.

"Pooh Bear" wrote in message
...
A balanced input costs very, very litle more than an unbalanced one
actually

Quite true in the world of pro audio. How many balanced systems do you find
in your local HiFi shop though?
I can't recall seeing any myself.

Even for pro audio use the current trend is going digital.
And AES3 digital audio is balanced.

And cat5 could be used.

MrT.

"Stewart Pinkerton" wrote in message
...
I'm talking about variations from the speaker's existing response, not
absolute flatness per se. And yes, a 1dB change is audible.

In an A-B test, which I already said.

(You don't need 100 millohms to get less than 1dB)

Depends on the speaker. OTOH, 100 milliohms isn't hard to achieve for
very little cost in most systems, so why not just take cable impedance
right out of the equation?

Which I already said, but has nothing to do with THIS case.

Says who? With most speakers it is simply overkill. Sure it is cheap easy
overkill which I also do myself, but to claim it is necessary, is not
true
in the *VAST* majority of cases.

I didn't say it was necessary, I said it was a reasonable and easily
achieved benchmark.

I'm glad you *now* agree it is just an easily achieved overkill.

ou could have 8 ohms of wire without problems
with the *constant* 4-ohm impedance of the KEF 104aBs I used to own,
due to their cunningly contrived constant impedance - but they would
have sounded like sh1t compared to modern speakers.

You really believe modern "white van" speakers are better than the KEFs?
Such unqualified statements are what caused this argument in the first
place.

Modern mainstream speakers of equivalent price is the obvious context.
Stop whining, just because you lost the argument.

Sorry I didn't realise there was judging, and you were the sole judge. You
really should understand the need to clearly define what you are talking
about BEFORE hand then. Not *after* someone questions your nebulous
statements.

Me either, but only because it's cheap and easy to do. I'm not silly
enough
to claim it is imperitive.

Neither is anyone else.

Good, I'm glad you have stopped then. Maybe we can get on with something
else.

Sheer conjecture.

Exactly, just like your statements.

Nope, you're just whining because your knee-jerk bull**** was
deconstructed.

Only in *your* opinion of course.
I'm glad I'm not so up myself as you are at least.

MrT.

"Mr.T" wrote:

"Pooh Bear" wrote in message
...
A balanced input costs very, very litle more than an unbalanced one
actually

Quite true in the world of pro audio.

It only needs a few exrta resistors if each input has an op-amp buffer.

How many balanced systems do you find
in your local HiFi shop though?
I can't recall seeing any myself.

Perfectly true. The tyranny of the utterly useless rca connector may be to
blame. That's not to say it's impossible to make hi-fi with balanced ins though.
Indeed there's simply no excuse for high end stuff not to.

Even for pro audio use the current trend is going digital.
And AES3 digital audio is balanced.

And cat5 could be used.

Only if you disregard the AES recommendation that AES3 be screened.

Graham

[Bertie the Bunyip]

Pooh Bear wrote in
:



David Nebenzahl wrote:

Dave Platt spake thus:

Whether this change in frequency response will be significant,
audible, or objectionable in a particular installation is likely to
be
a subjective issue. For medium-fi remote speakers, probably not...
but for critical listing with high-fidelity speakers it might very
well make the difference between an acceptable install and an
unacceptable one.

Well, I didn't address that point, because it's moot anyhow: if this
were an anal audio-fool's installation, they'd have 1-gauge copper
bus
connectors throughout the house, running inside industrial
noble-gas-filled conduit, for their speaker wiring. (Or maybe
superconducters.)

For anyone else, it makes practically NO difference.

You really do talk out of your ass you know.


Nettkkkpping ****.

interesting to see you work and play as wel with others just the same no
matter what the venue.




Bertie