Chevdo wrote:
John Atkinson is not expressing 'opinion' in Stereophile when
he allows the publication of articles which claim that magic
stones and tice clocks work.

When did I do that, Chevdo? Following Stereophile's coverage of
the Tice Clock, Tice canceled all of its advertising and has
had nothing to do with the magazine since. Regarding the Shakti
Stone, I had it reviewed by two people, one a high-end true
believer, the other a skeptic. Both reported similar impressions,
which I admit I found surprising. You can find the entirety of
Stereophile's coverage of these products in the magazine's free
on-line archives at www.stereophile.com, BTW..

That is a misrepresentation of fact, not opinion.

Nope, it is quite definitely the publishing of opinion.

It's also known as fraud.

Nope, you are wrong on that too. And yes, why _are_ you
doing this in r.a.p.? I have crossposted this response to
r.a.o. where this thread belongs, in my opinion.

John Atkinson
Editor, Stereophile

wrote:
Chevdo wrote:
John Atkinson is not expressing 'opinion' in Stereophile when
he allows the publication of articles which claim that magic
stones and tice clocks work.

When did I do that, Chevdo? Following Stereophile's coverage of
the Tice Clock, Tice canceled all of its advertising and has
had nothing to do with the magazine since. Regarding the Shakti
Stone, I had it reviewed by two people, one a high-end true
believer, the other a skeptic.

At the risk of being repititous... I read both reviews and still can't
tell... who was the skeptic?


ScottW

wrote in message
oups.com...

Chevdo wrote:
John Atkinson is not expressing 'opinion' in Stereophile when
he allows the publication of articles which claim that magic
stones and tice clocks work.

When did I do that, Chevdo? Following Stereophile's coverage of
the Tice Clock, Tice canceled all of its advertising and has
had nothing to do with the magazine since. Regarding the Shakti
Stone, I had it reviewed by two people, one a high-end true
believer, the other a skeptic.

Where can we find the measurements taken that demonstrate that Shakti Stones
have any real effect on an audio system?

Both reported similar impressions,

Which one has the measurements?

In article om,
"ScottW" wrote:

wrote:
Chevdo wrote:
John Atkinson is not expressing 'opinion' in Stereophile when
he allows the publication of articles which claim that magic
stones and tice clocks work.

When did I do that, Chevdo? Following Stereophile's coverage of
the Tice Clock, Tice canceled all of its advertising and has
had nothing to do with the magazine since. Regarding the Shakti
Stone, I had it reviewed by two people, one a high-end true
believer, the other a skeptic.

At the risk of being repititous... I read both reviews and still can't
tell... who was the skeptic?

TJN said he was "skeptically open-minded."

Stephen

wrote in message
oups.com

Chevdo wrote:
John Atkinson is not expressing 'opinion' in Stereophile
when he allows the publication of articles which claim
that magic stones and tice clocks work.

When did I do that, Chevdo? Following Stereophile's
coverage of the Tice Clock, Tice canceled all of its
advertising and has
had nothing to do with the magazine since. Regarding the
Shakti Stone, I had it reviewed by two people, one a
high-end true believer, the other a skeptic.

Given the low standards demonstrated by Stereophile when it
comes to audio skepticism...

Both reported similar impressions, which I admit I found
surprising.

(1) If a so-called skeptic reports similar impressions to a
non-skeptic, then he's obviously not really a skeptic.

(2) A true skeptic does not believe in anything but
skepticism, and he should be in doubt about that.

(3) A true skeptic will not affirm anything, he'll just
report his momentary inability to find any definate reason
to say that its all in error.


You can find the entirety of Stereophile's
coverage of these products in the magazine's free on-line
archives at www.stereophile.com, BTW..

FWIW...

On Mon, 24 Oct 2005 17:19:47 -0400, "Arny Krueger"
wrote:


(1) If a so-called skeptic reports similar impressions to a
non-skeptic, then he's obviously not really a skeptic.

Really, Arnie? What if the phenomenum both are observing exists?
Should not then both, having similar senses, report similar results,
skeptic or otherwise? Or are you suggesting that either skeptics or
non-skeptics are intrinsically liars?

"ScottW" wrote in message
ps.com...

wrote:
Chevdo wrote:
John Atkinson is not expressing 'opinion' in Stereophile when
he allows the publication of articles which claim that magic
stones and tice clocks work.

When did I do that, Chevdo? Following Stereophile's coverage of
the Tice Clock, Tice canceled all of its advertising and has
had nothing to do with the magazine since. Regarding the Shakti
Stone, I had it reviewed by two people, one a high-end true
believer, the other a skeptic.

At the risk of being repititous... I read both reviews and still can't
tell... who was the skeptic?


So what else is new?

"paul packer" wrote in message

On Mon, 24 Oct 2005 17:19:47 -0400, "Arny Krueger"
wrote:


(1) If a so-called skeptic reports similar impressions
to a non-skeptic, then he's obviously not really a
skeptic.

Really, Arnie? What if the phenomenum both are observing
exists?

OK Packer I take pity on you and now I spell it out for you:

Skepticism is a world view. Everything the skeptic sees is
affected by his world view, just like everything a
non-skeptic sees is affected by his world view.

A skeptic and a true believer looking at the same thing
can't possibly have the identically same impressions of it.

A true believer sees a full glass of water and has the
impression that the glass is full. A skeptic sees a glass of
water and has the impression that the glass appears to be
full.

Should not then both, having similar senses,
report similar results, skeptic or otherwise?

One word: nope.

Or are you suggesting that either skeptics or non-skeptics
are
intrinsically liars?

No, just that everybody's world view has a lot to do with
what their impressions fo the world are.

wrote in message
oups.com...

Chevdo wrote:
John Atkinson is not expressing 'opinion' in Stereophile when
he allows the publication of articles which claim that magic
stones and tice clocks work.

When did I do that, Chevdo? Following Stereophile's coverage of
the Tice Clock, Tice canceled all of its advertising and has
had nothing to do with the magazine since. Regarding the Shakti
Stone, I had it reviewed by two people, one a high-end true
believer, the other a skeptic. Both reported similar impressions,
which I admit I found surprising. You can find the entirety of
Stereophile's coverage of these products in the magazine's free
on-line archives at www.stereophile.com, BTW..

That is a misrepresentation of fact, not opinion.

Nope, it is quite definitely the publishing of opinion.

It's also known as fraud.

You allowed to be printed, priase for a device for which you have
(allegedly) the capability to measure the effects of, but did not do so.
The fact that it's efficacy was never verified is at the very least stupid
and sloppy, and at worst an endorsement of snake oil, not that that's
anything new.

The Bug Eater pleads for protection from the big, bad Snake Oil Establishment.

Following Stereophile's coverage of
the Tice Clock, Tice canceled all of its advertising and has
had nothing to do with the magazine since. Regarding the Shakti
Stone, I had it reviewed by two people, one a high-end true
believer, the other a skeptic. Both reported similar impressions,
which I admit I found surprising. You can find the entirety of
Stereophile's coverage of these products in the magazine's free
on-line archives at www.stereophile.com, BTW..
[This] is quite definitely the publishing of opinion.

You allowed to be printed,[sic] priase[sic] for a device for which you have
(allegedly) the capability to measure the effects of[sic], but did not do so.
The fact that it's[sic] efficacy was never verified is at the very least
stupid and sloppy, and at worst an endorsement of snake oil,[sic] not that
that's anything new.

Mickey, your ranting raises more than a few questions about your mental
competency. On the one hand, you claim these devices are "snake oil" (an
American idiom that means "worthless or fraudulent goods"). On the other hand,
you bleat about Stereophile not telling you they are "snake oil". Just one
question for you before you go back to banging your head on the sidewalk: If you
already know what you know, why do you need Stereophile to tell you anyway?


..
..
..
..

"George Middius" wrote in message
...



The Bug Eater pleads for protection from the big, bad Snake Oil
Establishment.

Following Stereophile's coverage of
the Tice Clock, Tice canceled all of its advertising and has
had nothing to do with the magazine since. Regarding the Shakti
Stone, I had it reviewed by two people, one a high-end true
believer, the other a skeptic. Both reported similar impressions,
which I admit I found surprising. You can find the entirety of
Stereophile's coverage of these products in the magazine's free
on-line archives at www.stereophile.com, BTW..
[This] is quite definitely the publishing of opinion.

You allowed to be printed,[sic] priase[sic] for a device for which you
have
(allegedly) the capability to measure the effects of[sic], but did not do
so.
The fact that it's[sic] efficacy was never verified is at the very least
stupid and sloppy, and at worst an endorsement of snake oil,[sic] not that
that's anything new.

Mickey, your ranting raises more than a few questions about your mental
competency. On the one hand, you claim these devices are "snake oil" (an
American idiom that means "worthless or fraudulent goods"). On the other
hand,
you bleat about Stereophile not telling you they are "snake oil". Just one
question for you before you go back to banging your head on the sidewalk:
If you
already know what you know, why do you need Stereophile to tell you
anyway?


.
As a sign of integrity from a magazine supposedly helpful to audiophiles.
Believe it or not there are people who might actually think a Shakti stone
might acutally do something for their stereo, just like there are people who
think that damping factor is an important specification for amplifiers.

"Arny Krueger" wrote in message
...
"paul packer" wrote in message

On Mon, 24 Oct 2005 17:19:47 -0400, "Arny Krueger"
wrote:


(1) If a so-called skeptic reports similar impressions
to a non-skeptic, then he's obviously not really a
skeptic.

Really, Arnie? What if the phenomenum both are observing
exists?

OK Packer I take pity on you and now I spell it out for you:

Skepticism is a world view. Everything the skeptic sees is
affected by his world view, just like everything a
non-skeptic sees is affected by his world view.

A skeptic and a true believer looking at the same thing
can't possibly have the identically same impressions of it.

A true believer sees a full glass of water and has the
impression that the glass is full. A skeptic sees a glass of
water and has the impression that the glass appears to be
full.

Arny, you are such a paradox.
The above is a very sophisticated worldview.
But it appears to me that you except yourself from it.
You appear to your adversaries on this group to be a true believer.
I anticipate your reply would be, "these are opinions you get to have."
If that is so, then my reply to you is, somewhere in the process of getting
these opinions, you picked up the mental baggage of a true believer.
This is a shame. With your apparent grasp of the subtleties, much more is
open to you.

"Robert Morein" wrote in message

"Arny Krueger" wrote in message
...
"paul packer" wrote in message

On Mon, 24 Oct 2005 17:19:47 -0400, "Arny Krueger"
wrote:


(1) If a so-called skeptic reports similar impressions
to a non-skeptic, then he's obviously not really a
skeptic.

Really, Arnie? What if the phenomenum both are observing
exists?

OK Packer I take pity on you and now I spell it out for
you:

Skepticism is a world view. Everything the skeptic sees
is affected by his world view, just like everything a
non-skeptic sees is affected by his world view.

A skeptic and a true believer looking at the same thing
can't possibly have the identically same impressions of
it.

A true believer sees a full glass of water and has the
impression that the glass is full. A skeptic sees a
glass of water and has the impression that the glass
appears to be full.

Arny, you are such a paradox.
The above is a very sophisticated worldview.

Really? I think it's pretty simple.

But it appears to me that you except yourself from it.

Hey Robert all sorts of things seem to appear to you that
don't actually exist.

You appear to your adversaries on this group to be a
true believer.

Believer in what?

I anticipate your reply would be, "these are opinions you
get to have."

I was thinking more along the lines of "You get to be
wrong". ;-)

If that is so, then my reply to you is, somewhere in the
process of getting these opinions, you picked up the
mental baggage of a true believer.

Speaks to your inability to relate to people as being
cohorts, Robert.

This is a shame. With your apparent grasp of the
subtleties, much more is open to you.

Much more than what?

But thanks for perceiving that I may actually know something
of value, Robert. I guess. :-(

wrote:

As a sign of integrity from a magazine supposedly helpful to audiophiles.
Believe it or not there are people who might actually think a Shakti stone
might acutally do something for their stereo, just like there are people who
think that damping factor is an important specification for amplifiers.

Damping factor *is* important albeit the the typical numbers quoted for SS amps
are so high as to be beyond worrying about from the perspective of choosing one
over another based on that parameter.

Graham

"Pooh Bear" wrote in message
...


wrote:

As a sign of integrity from a magazine supposedly helpful to
audiophiles.
Believe it or not there are people who might actually think a Shakti
stone
might acutally do something for their stereo, just like there are people
who
think that damping factor is an important specification for amplifiers.

Damping factor *is* important albeit the the typical numbers quoted for SS
amps
are so high as to be beyond worrying about from the perspective of
choosing one
over another based on that parameter.

Graham

For small signal conditions, yes.
But have you experienced the condition where one amplifier which is rated
nearly flat to 20 Hz provides noticeably inferior bass to another with
similar specs? The reason is that damping factor is not reported for large
signals. IMHO, this is one of the major shortcomings in the quantitative
analysis of amplifier performance.

On Tue, 25 Oct 2005 08:29:19 -0400, "Arny Krueger"
wrote:

"paul packer" wrote in message

On Mon, 24 Oct 2005 17:19:47 -0400, "Arny Krueger"
wrote:


(1) If a so-called skeptic reports similar impressions
to a non-skeptic, then he's obviously not really a
skeptic.

Really, Arnie? What if the phenomenum both are observing
exists?

OK Packer I take pity on you and now I spell it out for you:

Skepticism is a world view. Everything the skeptic sees is
affected by his world view, just like everything a
non-skeptic sees is affected by his world view.

Well, Arnie, let's assume there's only one ultimate reality.
A skeptic should be one who approaches something with a doubting
outlook, but if he finds truth or value in it, is nevertheless
prepared to admit that truth and value. Now either you're saying that
a skeptic is one who is unable to see any truth or value in anything
due to his blinding skepticism, or else he sees the truth and value
but refuses to admit it due to his adherence to the creed of
skepticism, in which case he's simply dishonest. Which is it?


A skeptic and a true believer looking at the same thing
can't possibly have the identically same impressions of it.

They can if that's what there.

A true believer sees a full glass of water and has the
impression that the glass is full. A skeptic sees a glass of
water and has the impression that the glass appears to be
full.

But they're both saying the same thing. The only difference is in the
interpretation.

Should not then both, having similar senses,
report similar results, skeptic or otherwise?

One word: nope.

That's one word alright.

Or are you suggesting that either skeptics or non-skeptics
are
intrinsically liars?

No, just that everybody's world view has a lot to do with
what their impressions fo the world are.

But ultimately their impressions can't deny or contradict reality. If
a stone is there in front of you, that's a reality and a fact. What
you're saying is that the fact of being a skeptic fatally colours your
impression of anything. If that's so, it says little for the creed of
skepticism, which I always imagined was an ally and tool of science.

"Pooh Bear" wrote in message
...


wrote:

As a sign of integrity from a magazine supposedly helpful to audiophiles.
Believe it or not there are people who might actually think a Shakti
stone
might acutally do something for their stereo, just like there are people
who
think that damping factor is an important specification for amplifiers.

Damping factor *is* important albeit the the typical numbers quoted for SS
amps
are so high as to be beyond worrying about from the perspective of
choosing one
over another based on that parameter.

Wrong, but thanks for playing.

"Robert Morein" wrote in message

"Pooh Bear"
wrote in message ...


wrote:

As a sign of integrity from a magazine supposedly
helpful to audiophiles. Believe it or not there are
people who might actually think a Shakti stone might
acutally do something for their stereo, just like there
are people who think that damping factor is an
important specification for amplifiers.

Damping factor *is* important albeit the the typical
numbers quoted for SS amps are so high as to be beyond
worrying about from the perspective of choosing one over
another based on that parameter.

For small signal conditions, yes.

For large signal conditions, yes as well.

But have you experienced the condition where one
amplifier which is rated nearly flat to 20 Hz provides
noticeably inferior bass to another with similar specs?

Obviously you haven't reliably experienced *anything*
relevant to your claims, Robert. A lot of your strange
perceptions seem to be related to the observable fact that
you hate doing listening tests where relevant variables are
maintained as stable as is reasonbly possible. For evidence
of your hatred for controlling relevant variables during amp
tests, anybody can see all your ranting and raving here
ABX.

ABX is just about basic experimental controls.

In addition Robert, I seriously doubt you are controlling
other relevant parameters, momentarily putting bias controls
aside. Things like level matching and checking frequency
response with real-world loads. If you were actually
monitoring these parameters, your posts would loose their
profound aroma of ignorance of real-world facts.

The reason is that damping factor is not reported for
large signals.

Don't know about that, but every time I've measured amp
source impedance at its output terminals with large signals,
nothing changes appreciably from the small signal numbers.

But Robert you're playing expert here. Why haven't you
delved into any of this stuff yourself? You say you're so
much smarter and wiser than I am - why do I have so much
practical experience with this relatively speaking, and you
demonstrate none?

Robert, is it that you are locked up some place where you
can't get your hands on sharp objects like meter probes?
Meter probes and all the stuff that goes with them are
readily availble for reasonable prices. Why aren't you more
familiar with their use in an audio context?

IMHO, this is one of the major
shortcomings in the quantitative analysis of amplifier
performance.

Only in your mind, Robert. For an amp's source impedance to
its load to change appreciably, it would have to be
appreciably nonlinear. Until you clip 'em, SS amps are
nothing if not linear at low frequencies where you started
ranting about in this post.

wrote in message
k.net
"Pooh Bear"
wrote in message ...


wrote:

As a sign of integrity from a magazine supposedly
helpful to audiophiles. Believe it or not there are
people who might actually think a Shakti stone
might acutally do something for their stereo, just like
there are people who
think that damping factor is an important specification
for amplifiers.

Damping factor *is* important albeit the the typical
numbers quoted for SS amps
are so high as to be beyond worrying about from the
perspective of choosing one
over another based on that parameter.

Wrong, but thanks for playing.

Well Graham actually knows this stuff pretty well, but he
seems to be kinda locked up in ancient terminology, that as
Dick Pierce says relate to parameters that are better
expressed in other terms.

Everbody should forget damping factor which is a joint
property of loads and amps, and just talk about amplifier
source impedance to its load, which is purely a property of
the amp.

If you know something about the load, its easy math to turn
source impedance numbers into damping factors.

"paul packer" wrote in message

On Tue, 25 Oct 2005 08:29:19 -0400, "Arny Krueger"
wrote:

"paul packer" wrote in message

On Mon, 24 Oct 2005 17:19:47 -0400, "Arny Krueger"
wrote:


(1) If a so-called skeptic reports similar impressions
to a non-skeptic, then he's obviously not really a
skeptic.

Really, Arnie? What if the phenomenum both are observing
exists?

OK Packer I take pity on you and now I spell it out for
you:

Skepticism is a world view. Everything the skeptic sees
is affected by his world view, just like everything a
non-skeptic sees is affected by his world view.

Well, Arnie, let's assume there's only one ultimate
reality.

Whatever that means.

A skeptic should be one who approaches something with a
doubting outlook, but if he finds truth or value in it,
is nevertheless prepared to admit that truth and value.

Whatever that means.

Now either you're saying that a skeptic is one who is
unable to see any truth or value in anything due to his
blinding skepticism, or else he sees the truth and value
but refuses to admit it due to his adherence to the creed
of skepticism, in which case he's simply dishonest. Which
is it?

Not at all.

A skeptic and a true believer looking at the same thing
can't possibly have the identically same impressions of
it.

They can if that's what there.

Not at all.

A true believer sees a full glass of water and has the
impression that the glass is full. A skeptic sees a
glass of water and has the impression that the glass
appears to be full.

But they're both saying the same thing.

Not at all.

The only difference is in the interpretation.

That, too.

Should not then both, having similar senses,
report similar results, skeptic or otherwise?

One word: nope.

That's one word alright.

Thanks for agreeing.

Or are you suggesting that either skeptics or
non-skeptics are
intrinsically liars?

No, just that everybody's world view has a lot to do with
what their impressions of the world are.

But ultimately their impressions can't deny or contradict
reality.


Sure they can. For example, people get things wrong all the
time. Errors and omissions, right?

If a stone is there in front of you, that's a
reality and a fact.

What is reality and what is a fact?

If you see a stone in front of you, in fact all you see is
one side of the stone. Who says that the other side has to
be there?

What you're saying is that the fact
of being a skeptic fatally colours your impression of
anything.

Skepticism is not always fatal. Many skeptics lead long and
happy lives.

f that's so, it says little for the creed of
skepticism, which I always imagined was an ally and tool
of science.

There's that imagination thing again, Paul.

I'm getting this feeling that the very concept of viewpoints
and their potentially profound effects is way over your
head, Paul.

Maybe John Atkinson's dumbed-down epistemology is ate limit
of your mental capabilities, Paul. Maybe even that is beyond
your ability to fathom.

Scary thoughts!

On Wed, 26 Oct 2005 10:20:42 -0400, "Arny Krueger"
wrote:

"paul packer" wrote in message

On Tue, 25 Oct 2005 08:29:19 -0400, "Arny Krueger"
wrote:

"paul packer" wrote in message

On Mon, 24 Oct 2005 17:19:47 -0400, "Arny Krueger"
wrote:


(1) If a so-called skeptic reports similar impressions
to a non-skeptic, then he's obviously not really a
skeptic.

Really, Arnie? What if the phenomenum both are observing
exists?

OK Packer I take pity on you and now I spell it out for
you:

Skepticism is a world view. Everything the skeptic sees
is affected by his world view, just like everything a
non-skeptic sees is affected by his world view.

Well, Arnie, let's assume there's only one ultimate
reality.

Whatever that means.

This is a worry, Arnie. Clearly for you skepticism is some kind of
religion which colours one's world view and prevents one seeing
reality. Is James Randi aware of this? I personally have little time
for "professional" skeptics, those who join skeptics societies and so
on, but I would certainly encourage healthy skepticism on any subject.
Or at least, I did, but now, having read your definition of a skeptic,
I'm beginning to wonder if I should shepherd the innocent away out of
danger. Obviously skepticism in your world is something to be avoided
at all costs.

A skeptic should be one who approaches something with a
doubting outlook, but if he finds truth or value in it,
is nevertheless prepared to admit that truth and value.

Whatever that means.

This is a mystery for you? Read it again and try harder this time.

(snip endless getting nowhere)

No, just that everybody's world view has a lot to do with
what their impressions of the world are.

But ultimately their impressions can't deny or contradict
reality.

Sure they can. For example, people get things wrong all the
time. Errors and omissions, right?

That's not denying reality. Reality just is. That's misinterpreting
reality.

What you're saying is that the fact
of being a skeptic fatally colours your impression of
anything.

Skepticism is not always fatal. Many skeptics lead long and
happy lives.

You forgot the smiley, Arnie. But it's nice to see you cracking a joke
occasionally, even a very weak one.

f that's so, it says little for the creed of
skepticism, which I always imagined was an ally and tool
of science.

There's that imagination thing again, Paul.

You mean a little healthy skepticism is not a handy tool for the
scientist?

I'm getting this feeling that the very concept of viewpoints
and their potentially profound effects is way over your
head, Paul.

Not at all, Arnie. I understand the effect your viewpoints have on you
very well.

Maybe John Atkinson's dumbed-down epistemology is ate limit
of your mental capabilities, Paul. Maybe even that is beyond
your ability to fathom.

From what I've read of Mr. Atkinson on this NG, I would not be ashamed
to be intellectually compared to him even by you, sarcastically. But
don't concern yourself about my ability to fathom things, Arnie. I do
alright.

"paul packer" wrote in message
...
On Tue, 25 Oct 2005 08:29:19 -0400, "Arny Krueger"
wrote:

"paul packer" wrote in message

On Mon, 24 Oct 2005 17:19:47 -0400, "Arny Krueger"
wrote:


(1) If a so-called skeptic reports similar impressions
to a non-skeptic, then he's obviously not really a
skeptic.

Really, Arnie? What if the phenomenum both are observing
exists?

OK Packer I take pity on you and now I spell it out for you:

Skepticism is a world view. Everything the skeptic sees is
affected by his world view, just like everything a
non-skeptic sees is affected by his world view.

Well, Arnie, let's assume there's only one ultimate reality.

Probably a safe bet.

A skeptic should be one who approaches something with a doubting
outlook, but if he finds truth or value in it, is nevertheless
prepared to admit that truth and value.

That sounds more like an Objectivist or a Realist.

Now either you're saying that
a skeptic is one who is unable to see any truth or value in anything
due to his blinding skepticism, or else he sees the truth and value
but refuses to admit it due to his adherence to the creed of
skepticism, in which case he's simply dishonest. Which is it?


Nope, a skeptic is one who doubts everything, including reality.


A skeptic and a true believer looking at the same thing
can't possibly have the identically same impressions of it.

They can if that's what there.

A true believer sees a full glass of water and has the
impression that the glass is full. A skeptic sees a glass of
water and has the impression that the glass appears to be
full.

But they're both saying the same thing. The only difference is in the
interpretation.

Should not then both, having similar senses,
report similar results, skeptic or otherwise?

One word: nope.

That's one word alright.

Or are you suggesting that either skeptics or non-skeptics
are
intrinsically liars?

No, just that everybody's world view has a lot to do with
what their impressions fo the world are.

But ultimately their impressions can't deny or contradict reality.

Yes they can, people deny reality all the time. There's a school of
thought, that says we can never know anything for sure due tot the fact that
all knowledge is filtered through our senses which are imperfect.

If
a stone is there in front of you, that's a reality and a fact.

That doens't mean it couldn't be a hallucination.

What
you're saying is that the fact of being a skeptic fatally colours your
impression of anything. If that's so, it says little for the creed of
skepticism, which I always imagined was an ally and tool of science.

Questioning the status quo to see if it agrees with reality is a bit
different than flat out skepicism. The sceintific method encourages the
former.

"paul packer" wrote in message

On Wed, 26 Oct 2005 10:20:42 -0400, "Arny Krueger"
wrote:

"paul packer" wrote in message

On Tue, 25 Oct 2005 08:29:19 -0400, "Arny Krueger"
wrote:

"paul packer" wrote in message

On Mon, 24 Oct 2005 17:19:47 -0400, "Arny Krueger"
wrote:


(1) If a so-called skeptic reports similar
impressions to a non-skeptic, then he's obviously
not really a skeptic.

Really, Arnie? What if the phenomenum both are
observing exists?

OK Packer I take pity on you and now I spell it out for
you:

Skepticism is a world view. Everything the skeptic sees
is affected by his world view, just like everything a
non-skeptic sees is affected by his world view.

Well, Arnie, let's assume there's only one ultimate
reality.

Whatever that means.

This is a worry, Arnie. Clearly for you skepticism is
some kind of religion which colours one's world view and
prevents one seeing reality.

Clearly you're on the attack again, Paul.

Is James Randi aware of this? I personally have little
time for "professional"
skeptics, those who join skeptics societies and so on,
but I would certainly encourage healthy skepticism on any
subject.

...in anybody but yourself it seems.

Or at least, I did, but now, having read your
definition of a skeptic, I'm beginning to wonder if I
should shepherd the innocent away out of danger.

I'm happy to leave the salvation of the world to you, Paul.

Obviously skepticism in your world is something to be
avoided at all costs.

Huh?

A skeptic should be one who approaches something with a
doubting outlook, but if he finds truth or value in it,
is nevertheless prepared to admit that truth and value.

Whatever that means.

This is a mystery for you? Read it again and try harder
this time.

Mentioning "skeptic" and "truth" in the same sentence can be
dangerous to your credibility, Paul.

(snip endless getting nowhere)

Whatever. Paul must do this to create the impression that
he's in control...

No, just that everybody's world view has a lot to do
with what their impressions of the world are.

But ultimately their impressions can't deny or
contradict reality.

Sure they can. For example, people get things wrong all
the time. Errors and omissions, right?

That's not denying reality.

You also said "contradict", didn't you Paul?

Reality just is.

Here's a news flash: Exactly what reality is depends on your
viewpoint, Paul.

That's misinterpreting reality.

Whose reality would that be?

What you're saying is that the fact
of being a skeptic fatally colours your impression of
anything.

Skepticism is not always fatal. Many skeptics lead long
and happy lives.

You forgot the smiley, Arnie. But it's nice to see you
cracking a joke occasionally, even a very weak one.

Nice job of not taking responsibility for what you said
Paul, part deux.

f that's so, it says little for the creed of
skepticism, which I always imagined was an ally and tool
of science.

There's that imagination thing again, Paul.

You mean a little healthy skepticism is not a handy tool
for the scientist?

Paul, you were talking about imagination.

Nice job of not taking responsibility for what you said
Paul, part tres.


I'm getting this feeling that the very concept of
viewpoints and their potentially profound effects is way
over your head, Paul.

Not at all, Arnie. I understand the effect your
viewpoints have on you very well.

That one went right over your pointy little ego-centric
head, didn't it Paul?

Maybe John Atkinson's dumbed-down epistemology is ate
limit of your mental capabilities, Paul. Maybe even that
is beyond your ability to fathom.

From what I've read of Mr. Atkinson on this NG, I would
not be ashamed to be intellectually compared to him even
by you, sarcastically.

It takes a certain lack of IQ to be impressed by his
prattle.

But don't concern yourself about
my ability to fathom things, Arnie. I do alright.

So you seem to think, Paul.

"Arny Krueger" wrote in message
...

Everbody should forget damping factor which is a joint property of loads
and amps, and just talk about amplifier source impedance to its load,
which is purely a property of the amp.

Agreed Zo is a figure that is pertinent to the amplifier, but
DF is important because the amplifier and its cables, plus
the speaker which it is driving should be regarded as an
entity when judging system performance.

If you know something about the load, its easy math to turn source
impedance numbers into damping factors.

Arny. Have you come across the writings of the legendary
British audio engineer Norman Crowhurst ? (He has published
several books and countless articles)

He states that the conventional method for DF measurement
Speaker impedance/Amp output impedance (Zspkr/Zo)
is incorrect,as the DC resistance of the voice coil should also
be taken into consideration, since it is a limiting factor in DF.

Using a value of 8R for the impedance of the speaker and
6R for the DC resistance, and an output impedance of 0.5R
we get:

Zls/(Zo+Rvc) = 8/(0.5+6) = 1.23.
Calculation by the traditional method gives: 16

Food for thought
Iain

wrote:

"Pooh Bear" wrote in message
...


wrote:

As a sign of integrity from a magazine supposedly helpful to audiophiles.
Believe it or not there are people who might actually think a Shakti
stone
might acutally do something for their stereo, just like there are people
who
think that damping factor is an important specification for amplifiers.

Damping factor *is* important albeit the the typical numbers quoted for SS
amps
are so high as to be beyond worrying about from the perspective of
choosing one
over another based on that parameter.

Wrong, but thanks for playing.

Well, actaully I'm right but then the fact that I'm a pro-audio designer might
explain why I know a bit more about this than you.

So what do you think it is that makes damping factor *unimportant* ?

Graham

"Pooh Bear" wrote
in message

So what do you think it is that makes damping factor
*unimportant* ?

It's not that damping factor isn't important, its that it is
an odd way to express the underlying physical parameter
which is amplifier source impedance.

For openers, damping factor isn't an amplifier parameter,
its a parameter that is also strongly dependent on load
impedance. Unfortunately the underlying physical parameter
remains pretty much unchanged, regardless of load impedance.

With good modern amps, the amplifier's damping factor is
generally so high that it gets swamped by all sorts of
things including voice coil DCR and speaker wire DCR.

It means a lot more with tubed amps.

On Wed, 26 Oct 2005 17:27:36 -0400, "Arny Krueger"
wrote:

"paul packer" wrote in message

On Wed, 26 Oct 2005 10:20:42 -0400, "Arny Krueger"
wrote:

"paul packer" wrote in message

On Tue, 25 Oct 2005 08:29:19 -0400, "Arny Krueger"
wrote:

"paul packer" wrote in message

On Mon, 24 Oct 2005 17:19:47 -0400, "Arny Krueger"
wrote:


(1) If a so-called skeptic reports similar
impressions to a non-skeptic, then he's obviously
not really a skeptic.

Really, Arnie? What if the phenomenum both are
observing exists?

OK Packer I take pity on you and now I spell it out for
you:

Skepticism is a world view. Everything the skeptic sees
is affected by his world view, just like everything a
non-skeptic sees is affected by his world view.

Well, Arnie, let's assume there's only one ultimate
reality.

Whatever that means.

This is a worry, Arnie. Clearly for you skepticism is
some kind of religion which colours one's world view and
prevents one seeing reality.

Clearly you're on the attack again, Paul.

Now who's being defensive?

Is James Randi aware of this? I personally have little
time for "professional"
skeptics, those who join skeptics societies and so on,
but I would certainly encourage healthy skepticism on any
subject.

..in anybody but yourself it seems.

No evidence for this remark, therefore it's a gratuitous insult.

Or at least, I did, but now, having read your
definition of a skeptic, I'm beginning to wonder if I
should shepherd the innocent away out of danger.

I'm happy to leave the salvation of the world to you, Paul.

Irrelevant remark made for effect.

Obviously skepticism in your world is something to be
avoided at all costs.

Huh?

Apologies. Poorly expressed on my part. What I meant was, your version
of skepticism is something I would avoid at all costs.

A skeptic should be one who approaches something with a
doubting outlook, but if he finds truth or value in it,
is nevertheless prepared to admit that truth and value.

Whatever that means.

This is a mystery for you? Read it again and try harder
this time.

Mentioning "skeptic" and "truth" in the same sentence can be
dangerous to your credibility, Paul.

The fact is, I adopt a skeptical attitude whenever I look at any
issue. Anyone who doesn't in these days of so much charlatanism and
deception is a fool. But why should my skeptical attitude ultimately
prevent me from accepting the truth or value of something? Unless one
has turned it into some kind of creed or religion that causes a skewed
vision of things, skepticism should merely be a defence against
gullibility and a spur to investigation. In other words, I regard
skepticism as a tool to get at the truth, not a contradiction of it.

(snip endless getting nowhere)

Whatever. Paul must do this to create the impression that
he's in control...

Another irrelevant remark made for effect.

No, just that everybody's world view has a lot to do
with what their impressions of the world are.

But ultimately their impressions can't deny or
contradict reality.

Sure they can. For example, people get things wrong all
the time. Errors and omissions, right?

That's not denying reality.

You also said "contradict", didn't you Paul?

Reality just is.

Here's a news flash: Exactly what reality is depends on your
viewpoint, Paul.

Not really, Arnie. You see different things at different times,
depending on your mental state/level of consciousness. But that
doesn't in any way change what is actually there. However you may
percieve it, the thing itself is a constant. Two people may perceive
something ten different ways, but the reality of the thing remains as
before--beyond the vagaries of perception and untouched by your
particular perception, which in fact has only to do with yourself.

That's misinterpreting reality.

Whose reality would that be?

The ultimate one.

What you're saying is that the fact
of being a skeptic fatally colours your impression of
anything.

Skepticism is not always fatal. Many skeptics lead long
and happy lives.

You forgot the smiley, Arnie. But it's nice to see you
cracking a joke occasionally, even a very weak one.

Nice job of not taking responsibility for what you said
Paul, part deux.

Whatever that means

f that's so, it says little for the creed of
skepticism, which I always imagined was an ally and tool
of science.

There's that imagination thing again, Paul.

You mean a little healthy skepticism is not a handy tool
for the scientist?

Paul, you were talking about imagination.

Nice job of not taking responsibility for what you said
Paul, part tres.

Whatever that means

I'm getting this feeling that the very concept of
viewpoints and their potentially profound effects is way
over your head, Paul.

Not at all, Arnie. I understand the effect your
viewpoints have on you very well.

That one went right over your pointy little ego-centric
head, didn't it Paul?

Can't handle an arrow fired straight back at you without adopting a
spurious air of superiority, Arnie?

Maybe John Atkinson's dumbed-down epistemology is ate
limit of your mental capabilities, Paul. Maybe even that
is beyond your ability to fathom.

From what I've read of Mr. Atkinson on this NG, I would
not be ashamed to be intellectually compared to him even
by you, sarcastically.

It takes a certain lack of IQ to be impressed by his
prattle.

You know, you're sounding a little like Robert. Best be careful there.
:-)

"Arny Krueger" wrote in message
...
"Robert Morein" wrote in message

"Pooh Bear"
wrote in message ...


wrote:

As a sign of integrity from a magazine supposedly
helpful to audiophiles. Believe it or not there are
people who might actually think a Shakti stone might
acutally do something for their stereo, just like there
are people who think that damping factor is an
important specification for amplifiers.

Damping factor *is* important albeit the the typical
numbers quoted for SS amps are so high as to be beyond
worrying about from the perspective of choosing one over
another based on that parameter.

For small signal conditions, yes.

For large signal conditions, yes as well.

But have you experienced the condition where one
amplifier which is rated nearly flat to 20 Hz provides
noticeably inferior bass to another with similar specs?

Obviously you haven't reliably experienced *anything* relevant to your
claims, Robert. A lot of your strange perceptions seem to be related to
the observable fact that you hate doing listening tests where relevant
variables are maintained as stable as is reasonbly possible. For evidence
of your hatred for controlling relevant variables during amp tests,
anybody can see all your ranting and raving here ABX.

ABX is just about basic experimental controls.

In addition Robert, I seriously doubt you are controlling other relevant
parameters, momentarily putting bias controls aside. Things like level
matching and checking frequency response with real-world loads. If you
were actually monitoring these parameters, your posts would loose their
profound aroma of ignorance of real-world facts.

The reason is that damping factor is not reported for
large signals.

Don't know about that, but every time I've measured amp source impedance
at its output terminals with large signals, nothing changes appreciably
from the small signal numbers.

Hi Arny. This DF business is something that interests me in
trying top find out why amplifiers that have similar FR and
PBW perform differently into a less-than benign load.

I made up a resistive box of 4R and 12R in series, with a switch
across the 12R to short it out. I then measured the voltages
across R1 and R2 (calling them V1 and V2)

Then using the formula: (V1-V2) / ((V2/16) - (V1/4))
I calculated the output impedance Zo of the amplifiers
in which I was interested. From this, using 8 / Zo, I
could calculate the DF.

I am told that various companies measure Zo at 400Hz
700Hz or 1kHz. I got very similar figures at all these frequencies.
I also found that there was no variation with power either
which confirms what you have stated.

Iain

"paul packer" wrote in message

On Wed, 26 Oct 2005 17:27:36 -0400, "Arny Krueger"
wrote:


Mentioning "skeptic" and "truth" in the same sentence
can be dangerous to your credibility, Paul.

The fact is, I adopt a skeptical attitude whenever I look
at any issue. Anyone who doesn't in these days of so much
charlatanism and deception is a fool. But why should my
skeptical attitude ultimately prevent me from accepting
the truth or value of something? Unless one has turned it
into some kind of creed or religion that causes a skewed
vision of things, skepticism should merely be a defence
against gullibility and a spur to investigation. In other
words, I regard skepticism as a tool to get at the truth,
not a contradiction of it.

OK Paul, so your skepticism has this gigantic blind spot
when it comes to audio.

Reality just is.

Here's a news flash: Exactly what reality is depends on
your viewpoint, Paul.

Not really, Arnie. You see different things at different
times, depending on your mental state/level of
consciousness. But that doesn't in any way change what is
actually there.

I never said it did.

However you may percieve it, the thing
itself is a constant.

Unless it is varying, which almost everything is.

Two people may perceive something
ten different ways, but the reality of the thing remains
as before--beyond the vagaries of perception and
untouched by your particular perception, which in fact
has only to do with yourself.

Paul, you never studied modern physics, I take it.

That's misinterpreting reality.

Whose reality would that be?

The ultimate one.

Are there others?

"Iain M Churches" wrote in message


Hi Arny. This DF business is something that interests me
in trying top find out why amplifiers that have similar FR
and PBW perform differently into a less-than benign load.

I made up a resistive box of 4R and 12R in series, with a
switch across the 12R to short it out. I then measured
the voltages across R1 and R2 (calling them V1 and V2)

Then using the formula: (V1-V2) / ((V2/16) - (V1/4))
I calculated the output impedance Zo of the amplifiers
in which I was interested. From this, using 8 / Zo, I
could calculate the DF.

That's one way to do it. Pretty classic and of course very
good as far as it goes.

I am told that various companies measure Zo at 400Hz
700Hz or 1kHz.

That's typical. Those frequencies aren't far apart for an
amplifier test. If you want to see Zo vary, go to the
frequency response extremes.

I got very similar figures at all these
frequencies. I also found that there was no variation
with power either which confirms what you have stated.

Thanks for the confirmation, as your methodology is classic.

Here are examples of some of my Zo measurements:

http://www.pcavtech.com/pwramp/macrot-5000VZ/zout.gif

http://www.pcavtech.com/techtalk/wir...4BSTleft-z.gif

http://www.pcavtech.com/techtalk/wir...ST-left-ph.gif

The methodology I use is dynamic. I can change the operating
conditions and the plot data on my PC screen in real time. I
can test Zo using loudspeaker and loudspeaker-like loads. I
can use actual recordings of music to drive the test rig.
I've collected a lot of informal data about how Zo varies
under different operating conditions. For good amps, it
doesn't.

"Pooh Bear" wrote in message
...


wrote:

"Pooh Bear" wrote in message
...


wrote:

As a sign of integrity from a magazine supposedly helpful to
audiophiles.
Believe it or not there are people who might actually think a Shakti
stone
might acutally do something for their stereo, just like there are
people
who
think that damping factor is an important specification for
amplifiers.

Damping factor *is* important albeit the the typical numbers quoted for
SS
amps
are so high as to be beyond worrying about from the perspective of
choosing one
over another based on that parameter.

Wrong, but thanks for playing.

Well, actaully I'm right but then the fact that I'm a pro-audio designer
might
explain why I know a bit more about this than you.


How about this then, some sort of damping factor is a requirement for an
amp, but as a determining factor it is of no particular importance. As I
said elsewhere it could be as low as 1 or as high as 500 and it doesn't make
a big difference.

So what do you think it is that makes damping factor *unimportant* ?




Follow the link I gave for Dick Pierce's paper on the subject. Or just do a
Google search for Dick Pierce and Damping factor.

"Arny Krueger" wrote in message
...
"Pooh Bear" wrote
in message

So what do you think it is that makes damping factor
*unimportant* ?

It's not that damping factor isn't important, its that it is an odd way to
express the underlying physical parameter which is amplifier source
impedance.

For openers, damping factor isn't an amplifier parameter, its a parameter
that is also strongly dependent on load impedance. Unfortunately the
underlying physical parameter remains pretty much unchanged, regardless of
load impedance.

With good modern amps, the amplifier's damping factor is generally so high
that it gets swamped by all sorts of things including voice coil DCR and
speaker wire DCR.

It means a lot more with tubed amps.


Which is probably why it was ever expressed as a value at all. When they
came up with it, tubes were dominant, then came good more accurate, less
volatile, transistors. :-)

wrote:

"Arny Krueger" wrote in message
...
"Pooh Bear" wrote
in message

So what do you think it is that makes damping factor
*unimportant* ?

It's not that damping factor isn't important, its that it is an odd way to
express the underlying physical parameter which is amplifier source
impedance.

For openers, damping factor isn't an amplifier parameter, its a parameter
that is also strongly dependent on load impedance. Unfortunately the
underlying physical parameter remains pretty much unchanged, regardless of
load impedance.

With good modern amps, the amplifier's damping factor is generally so high
that it gets swamped by all sorts of things including voice coil DCR and
speaker wire DCR.

It means a lot more with tubed amps.


Which is probably why it was ever expressed as a value at all. When they
came up with it, tubes were dominant, then came good more accurate, less
volatile, transistors. :-)

Whether tube ( valve ) or transistor - damping factor ( a reciprocal measure of
amplifer output impedance ) is important.

A low damping factor means that an amplifier cannot adequately control speaker
resonances or the back emf caused by transients.

From the aspect of resonances - a 'poor' i.e. low damping factor will tend to
result in a possibly initially flattering bass rise around speaker resonance
with typical ported enclosures. This is well documented. The resulting bass is
also poorly controlled though leading to 'farty bass'.

The inability of an amplifier to control the back emf from the motor coil will
also result in signal degradation.

Note that the resistance of the cabling between amp and speaker affects damping
factor too. That's one reason why damping factor *in isolation* is misleading
perhaps. The resistance of the speaker cable appears in series with the
amplifier output impedance. This is why speaker wiring should be of the largest
practical gauge in order to reduce its resistance.

Having said that..... it was IME rare for tube amps to have better damping
factor than say ~ 15-20. Translating to an output impedance of maybe a few
hundred milliohms to an ohm. Likely the cable resistance made little difference.

Modern SS amps can have output impedances easily as low as in the tens of
milliohm region. This makes cable resistance much more critical in comparing one
with another ( along with bi-wiring etc... ).

Graham

"Pooh Bear" wrote
in message
wrote:

"Arny Krueger" wrote in message
...
"Pooh Bear"
wrote
in message

So what do you think it is that makes damping factor
*unimportant* ?

It's not that damping factor isn't important, its that
it is an odd way to express the underlying physical
parameter which is amplifier source impedance.

For openers, damping factor isn't an amplifier
parameter, its a parameter that is also strongly
dependent on load impedance. Unfortunately the
underlying physical parameter remains pretty much
unchanged, regardless of load impedance.

With good modern amps, the amplifier's damping factor
is generally so high that it gets swamped by all sorts
of things including voice coil DCR and speaker wire DCR.

It means a lot more with tubed amps.


Which is probably why it was ever expressed as a value
at all. When they came up with it, tubes were dominant,
then came good more accurate, less volatile,
transistors. :-)

Whether tube ( valve ) or transistor - damping factor ( a
reciprocal measure of amplifer output impedance ) is
important.

A low damping factor means that an amplifier cannot
adequately control speaker resonances or the back emf
caused by transients.

This would be a common misconception.

When one designs a speaker system, the source impedance of
the amplifier is simply part of the design of the speaker.

For example, if you *know* that the amp has a source
impedance of one ohm, you simply design for that operational
condition. You plug one ohm into the Thiel/small parameters
for the woofer, and you plug one ohm into the design of the
crossovers.

Do the designing right, and you end up with a speaker that
is no more (or less) resonant.

This isn't just a theoretical oddity. It's very practical.

No less than Ken Kantor designed and brought to market a
line of pro audio powered speakers that used standard 20
gauge XLR cables for speaker cable. By all accounts they
were technically sucessful. The resistance of the speaker
cable was part of the design. But, the resistance could have
been part of the design of the amps.

I've also seen and heard speaker cable resistance plugged
into the design of large theatre speakers. Yet another
technical success.

The lesson is that mismatches between speaker design and amp
performance should be avoided. This was more common when
solid state amps first came out. Most speakers from the
tubed era were designed to work with an amp source impdance
of about an ohm. Swap in a SS amp and some heavy speaker
cable, and its a different world.

Source impedance effects were more common with early SS amps
that had output coupling caps. Some woofers (example: AR3)
can turn these into remarkably effective bass boost
circuits. Other speakers are affected far less. The hidden
gotcha is a output coupling cap that is outside the feedback
loop. Still found in some modern amps that have unusual
power supply arrangements.

Pooh Bear said:

Whether tube ( valve ) or transistor - damping factor ( a reciprocal measure of
amplifer output impedance ) is important.


Recently, someone wrote (Arny?) that "damping factor" isn't the right
term in this regard.
He pleaded for using the term "amplifier's internal output impedance",
which seems to be more appropriate here.

I can agree with that.

--

"Audio as a serious hobby is going down the tubes."
- Howard Ferstler, 25/4/2005

"Pooh Bear" wrote in message
...
A low damping factor means that an amplifier cannot adequately control
speaker
resonances or the back emf caused by transients.

From the aspect of resonances - a 'poor' i.e. low damping factor will tend
to
result in a possibly initially flattering bass rise around speaker
resonance
with typical ported enclosures. This is well documented. The resulting
bass is
also poorly controlled though leading to 'farty bass'.

The inability of an amplifier to control the back emf from the motor coil
will
also result in signal degradation.

Note that the resistance of the cabling between amp and speaker affects
damping
factor too. That's one reason why damping factor *in isolation* is
misleading
perhaps. The resistance of the speaker cable appears in series with the
amplifier output impedance. This is why speaker wiring should be of the
largest
practical gauge in order to reduce its resistance.

Having said that..... it was IME rare for tube amps to have better damping
factor than say ~ 15-20. Translating to an output impedance of maybe a few
hundred milliohms to an ohm. Likely the cable resistance made little
difference.

Modern SS amps can have output impedances easily as low as in the tens of
milliohm region. This makes cable resistance much more critical in
comparing one
with another ( along with bi-wiring etc... ).

Graham

Yes. That's as I understand it.
The valve amp designer who interests me the most, Arthur Radford,
produced during the 1960s a 100W amp for studio use with a DF of 60.
He did state however that above a figure or 15 or so, the increase in
DF had negligible effect. I have also seen this stated by Norman Cowhurst
and by Howard Tremaine in his broadcast industry training manual from
the 1970s, the Audio Cyclopedia.

Iain

"Arny Krueger" wrote in message
. ..
"Pooh Bear" wrote
in message
wrote:

"Arny Krueger" wrote in message
...
"Pooh Bear"
wrote
in message

So what do you think it is that makes damping factor
*unimportant* ?

It's not that damping factor isn't important, its that
it is an odd way to express the underlying physical
parameter which is amplifier source impedance.

For openers, damping factor isn't an amplifier
parameter, its a parameter that is also strongly
dependent on load impedance. Unfortunately the
underlying physical parameter remains pretty much
unchanged, regardless of load impedance.

With good modern amps, the amplifier's damping factor
is generally so high that it gets swamped by all sorts
of things including voice coil DCR and speaker wire DCR.

It means a lot more with tubed amps.


Which is probably why it was ever expressed as a value
at all. When they came up with it, tubes were dominant,
then came good more accurate, less volatile,
transistors. :-)

Whether tube ( valve ) or transistor - damping factor ( a
reciprocal measure of amplifer output impedance ) is
important.

A low damping factor means that an amplifier cannot
adequately control speaker resonances or the back emf
caused by transients.

This would be a common misconception.

When one designs a speaker system, the source impedance of the amplifier
is simply part of the design of the speaker.

For example, if you *know* that the amp has a source impedance of one ohm,
you simply design for that operational condition. You plug one ohm into
the Thiel/small parameters for the woofer, and you plug one ohm into the
design of the crossovers.

But that's the problem, Arny, you don't know, unless you are
perhaps a broadcast engineer specifying a complete audio chain.

People expect their new amp to work with their existing
speakers, and vice versa. If these speakers present a difficult
load, or do not comply with the recommendations of
IEC/EN/BS EN 60268-5 they may find themselves sadly
disappointed.

SETs can produce the most wonderful small-ensemble music
at lowish levels with full range horns, but try one with an ELS.

Do the designing right, and you end up with a speaker that is no more (or
less) resonant.

Few if any of us design our own speakers.

Iain

"Arny Krueger" wrote in message
...
"Iain M Churches" wrote in message



Hi Arny. Good to be discussing something of mutual
interest with you. I have rather lost track of whether
you though Zo and DF were important or unimportant
factors in the evaluation of a valve amplifier.

Can you please confirm your position?

I made up a resistive box of 4R and 12R in series, with a
switch across the 12R to short it out. I then measured
the voltages across R1 and R2 (calling them V1 and V2)

(snip. my methodology)

That's one way to do it. Pretty classic and of course very
good as far as it goes.

Please elaborate. If there are shortcomings in this method
I would be interested to hear of them. I know you have
considerable experience in this field.

I know of three static methods (there may be more)
The original classic way seems to be to inject a low level signal
into an amp, and then measure the output voltage with no load.
Then add a variable wirewound resistor and adjust it until
the Vo falls by 6dB. This resistance is then equal to the
Zo of the amp. This is a simple method, but assumes that
all amplifiers are stable into an open circuit.

I am told that various companies measure Zo at 400Hz
700Hz or 1kHz.

That's typical. Those frequencies aren't far apart for an amplifier test.
If you want to see Zo vary, go to the frequency response extremes.

I did that, but into my 4 and 16 Ohms resistive load.
There was very little variance. I feel that the same
measurements into a real-world load would yield
different results (more of that later)

I got very similar figures at all these
frequencies. I also found that there was no variation
with power either which confirms what you have stated.

Thanks for the confirmation, as your methodology is classic.

Here are examples of some of my Zo measurements:

http://www.pcavtech.com/pwramp/macrot-5000VZ/zout.gif

http://www.pcavtech.com/techtalk/wir...4BSTleft-z.gif

http://www.pcavtech.com/techtalk/wir...ST-left-ph.gif

The methodology I use is dynamic. I can change the operating conditions
and the plot data on my PC screen in real time. I can test Zo using
loudspeaker and loudspeaker-like loads. I can use actual recordings of
music to drive the test rig. I've collected a lot of informal data about
how Zo varies under different operating conditions. For good amps, it
doesn't.

I know of a static third method, which involves using both channels
of a stereo amp. The dummy load is connected between the
output of one channel which is driving with a smallish input
signal, and the output of the other channel which has no signal
at its input.

I would be interested to hear about your dynamic testing,
Arny. I have access to a broadcast facility lab.

I thought your PC plots were good. I use Excel and enter the
data into two columns and let the software plot the chart,
in four colours on log paper which looks even better.

I am interested in what you term loudspeaker-like loads. By
this I presume you mean simulated loads. I am in the process
of building one of these from the circuit published in Stereophile
and designed by Ken Kantor

http://www.stereophile.com/reference/60

It represents a smallish two way speaker. I am interested also to
find a schematic that simulates a large studio three way
design.

Lets's forget Mikey falling down for the moment.
I have renamed this part of the thread.

Cordially,

Iain

Iain M Churches said to Arnii "Blowhard" Krooborg:

Do the designing right, and you end up with a speaker that is no more (or
less) resonant.

Few if any of us design our own speakers.

Especially Arnii Krooger.



..
..
..
..

"Iain M Churches" wrote in message

"Arny Krueger" wrote in message
...
"Iain M Churches" wrote in message



Hi Arny. Good to be discussing something of mutual
interest with you. I have rather lost track of whether
you though Zo and DF were important or unimportant
factors in the evaluation of a valve amplifier.

Can you please confirm your position?

I think that Zo is an important parameter for every power
amp that ever drives a load whose impedance is
frequency-dependent.

I made up a resistive box of 4R and 12R in series, with
a switch across the 12R to short it out. I then
measured the voltages across R1 and R2 (calling them V1
and V2)

(snip. my methodology)

That's one way to do it. Pretty classic and of course
very good as far as it goes.

Please elaborate. If there are shortcomings in this method
I would be interested to hear of them. I know you have
considerable experience in this field.

The method I use is to measure the output impedance of the
power amp by treating it like it is just another impedance.
I use a second power amp plus an isolating resistor as the
signal source for the measurement. I measure the voltage
across the UUT, as well as the current flowing into it.
SpectraLab software calculates the quotient of the two
signals in the frequency domain in real time to produce a
plot of impedance magnitude and phase versus frequency.

Since the results are based on a quotient, the procedure
works with a wide variety of signals, signal levels, and
other test conditions.

There are a number of pieces of measurement software that
perform similar calculations. Sample Champion from
http://www.purebits.com/ is an relatively inexpensive
package that does a similar calculation as described in this
appliation note: http://purebits.com/appnote16.html .


I know of three static methods (there may be more)
The original classic way seems to be to inject a low
level signal into an amp, and then measure the output
voltage with no load. Then add a variable wirewound
resistor and adjust it until the Vo falls by 6dB. This
resistance is then equal to the
Zo of the amp. This is a simple method, but assumes that
all amplifiers are stable into an open circuit.

I am told that various companies measure Zo at 400Hz
700Hz or 1kHz.

That's typical. Those frequencies aren't far apart for
an amplifier test. If you want to see Zo vary, go to the
frequency response extremes.

I did that, but into my 4 and 16 Ohms resistive load.
There was very little variance. I feel that the same
measurements into a real-world load would yield
different results (more of that later)

If the amplifier that I use as the signal source has a low
output impedance and is robust, when it sources the test
signal to the UUT though a loudspeaker or loudspeaker-like
load, then the UUT's response to working with the given load
becomes part of the test.

I got very similar figures at all these
frequencies. I also found that there was no variation
with power either which confirms what you have stated.

Thanks for the confirmation, as your methodology is
classic.

Here are examples of some of my Zo measurements:

http://www.pcavtech.com/pwramp/macrot-5000VZ/zout.gif

http://www.pcavtech.com/techtalk/wir...4BSTleft-z.gif

http://www.pcavtech.com/techtalk/wir...ST-left-ph.gif

The methodology I use is dynamic. I can change the
operating conditions and the plot data on my PC screen
in real time. I can test Zo using loudspeaker and
loudspeaker-like loads. I can use actual recordings of
music to drive the test rig. I've collected a lot of
informal data about how Zo varies under different
operating conditions. For good amps, it doesn't.

I know of a static third method, which involves using
both channels of a stereo amp. The dummy load is
connected between the output of one channel which is
driving with a smallish
input signal, and the output of the other channel which
has no signal.

That's the starting point for the procedure I use.
at its input.

I would be interested to hear about your dynamic testing,
Arny. I have access to a broadcast facility lab.

I thought your PC plots were good. I use Excel and enter
the data into two columns and let the software plot the
chart,
in four colours on log paper which looks even better.

I am interested in what you term loudspeaker-like loads.
By this I presume you mean simulated loads. I am in the
process of building one of these from the circuit
published in
Stereophile and designed by Ken Kantor

http://www.stereophile.com/reference/60

It represents a smallish two way speaker. I am interested
also to find a schematic that simulates a large studio
three way design.

Lets's forget Mikey falling down for the moment.
I have renamed this part of the thread.

Cordially,

Iain