[Joe Kramer]

Hi Friends,

I have built several mics based on Panasonic electret elements and the
electronically balanced output circuit I got from the old Recording
Magazine article by Scott Dorsey.

My question is whether the so-called "Linkwitz mod" would apply to this
circuit. I'm guessing it would not, since the source of the capsule's
internal FET is made to float above ground in the balanced scheme, but
I'm not totally sure of my conclusion. I have tried the balanced
circuit with the mod, but found it made little difference, except that
the case of the capsule needed a separate ground connection. Any help
on this would be much appreciated. Thanks.

Regards,
Joe Kramer

PS: Balanced output schemo similar to S. Dorsey's he

http://mp3forkidz.com/mic/phantxy.html

Linkwitz Mod he

http://www.linkwitzlab.com/images/graphics/microph1.gif

[Mark]

On Sep 26, 4:30 pm, Joe Kramer wrote:
Hi Friends,

I have built several mics based on Panasonic electret elements and the
electronically balanced output circuit I got from the old Recording
Magazine article by Scott Dorsey.

My question is whether the so-called "Linkwitz mod" would apply to this
circuit. I'm guessing it would not, since the source of the capsule's
internal FET is made to float above ground in the balanced scheme, but
I'm not totally sure of my conclusion. I have tried the balanced
circuit with the mod, but found it made little difference, except that
the case of the capsule needed a separate ground connection. Any help
on this would be much appreciated. Thanks.

Regards,
Joe Kramer

PS: Balanced output schemo similar to S. Dorsey's he

http://mp3forkidz.com/mic/phantxy.html

Linkwitz Mod he

http://www.linkwitzlab.com/images/graphics/microph1.gif

I'm curious about 2 things...

1) Are the electret elements omni or directional? I have some
inexepensive electret elements that are very good but they are omni.

2) What difference do you expect with a balanced output? An
electricaly floating mic (i.e. one that has no external electical
connection to ground) is inherently balanced even if the internal
schematic shows a local ground.

thanks
Mark

[Scott Dorsey]

Joe Kramer wrote:
I have built several mics based on Panasonic electret elements and the
electronically balanced output circuit I got from the old Recording
Magazine article by Scott Dorsey.

Okay, now, if you look at this circuit, you will see that the "ground"
or case of the microphone is floating above the actual system ground.
How much it floats will depend on the capsule you use, but you can
measure it.

My question is whether the so-called "Linkwitz mod" would apply to this
circuit. I'm guessing it would not, since the source of the capsule's
internal FET is made to float above ground in the balanced scheme, but
I'm not totally sure of my conclusion. I have tried the balanced
circuit with the mod, but found it made little difference, except that
the case of the capsule needed a separate ground connection. Any help
on this would be much appreciated. Thanks.

I believe you are talking about cutting the connection between the case
of the microphone and the normally-grounded FET pin of the microphone,
and adding a resistor so that the FET is floating above ground by a
couple volts.

You should be able to do this in conjunction with the balanced circuit,
BUT you need to forget about the system ground. The source of the FET
is already a couple volts above the system ground... you now will probably
want to connect the case of the microphone to a resistive divider that
goes between ground and the 12V line so you can adjust the voltage of the
case without changing the voltage of the source. I'd try just putting
a 10K pot between ground and the 12V line, connecting that to the case,
and adjusting it until it's right.
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."

[Scott Dorsey]

Mark wrote:
I'm curious about 2 things...

1) Are the electret elements omni or directional? I have some
inexepensive electret elements that are very good but they are omni.

In general it is much easier to make good cheap omnis than good cheap
directional mikes. Both the cheap Panasonic and Knowles capsules are
available from digi-key. They both make omnis and cardioids, and in
both cases the omnis are much better.

Then again, you could argue the same is true of every other microphone
at every other price range, on up to Schoeps and DPA.

2) What difference do you expect with a balanced output? An
electricaly floating mic (i.e. one that has no external electical
connection to ground) is inherently balanced even if the internal
schematic shows a local ground.

The big deal is you can use phantom power with the circuit cited.
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."

[Richard Crowley]

"Scott Dorsey" wrote ...
I believe you are talking about cutting the connection between the case
of the microphone and the normally-grounded FET pin of the microphone,
and adding a resistor so that the FET is floating above ground by a
couple volts.

You should be able to do this in conjunction with the balanced circuit,
BUT you need to forget about the system ground. The source of the FET
is already a couple volts above the system ground... you now will probably
want to connect the case of the microphone to a resistive divider that
goes between ground and the 12V line so you can adjust the voltage of the
case without changing the voltage of the source. I'd try just putting
a 10K pot between ground and the 12V line, connecting that to the case,
and adjusting it until it's right.

But if you cut the connection between the case and the FET
source node, is there any DC path left between the case and
any part of the circuit? Why wouldn't one just ground the case
(pin-1, microphone shell ground) for maximum shielding?

[Arny Krueger]

"Joe Kramer" wrote in message

Hi Friends,

I have built several mics based on Panasonic electret
elements and the electronically balanced output circuit I
got from the old Recording Magazine article by Scott
Dorsey.
My question is whether the so-called "Linkwitz mod" would
apply to this circuit. I'm guessing it would not, since
the source of the capsule's internal FET is made to float
above ground in the balanced scheme, but I'm not totally
sure of my conclusion. I have tried the balanced circuit
with the mod, but found it made little difference, except
that the case of the capsule needed a separate ground
connection. Any help on this would be much appreciated. Thanks.
Regards,
Joe Kramer

PS: Balanced output schemo similar to S. Dorsey's he

http://mp3forkidz.com/mic/phantxy.html

Linkwitz Mod he

http://www.linkwitzlab.com/images/graphics/microph1.gif


The Linkwitz mod looks great on paper, but has anybody actually tested its
effects in real-world high-SPL soundfields to see if it has any actual
beneficial effects?

[Eeyore]

Joe Kramer wrote:

Linkwitz Mod he

http://www.linkwitzlab.com/images/graphics/microph1.gif

That's not a balanced connection. That's a 'computer mic' type connection.

Why do you want to make some kind of 'hybrid' ?

Graham

[[email protected]]

"Arny Krueger" writes:

"Joe Kramer" wrote in message

Hi Friends,

I have built several mics based on Panasonic electret
elements and the electronically balanced output circuit I
got from the old Recording Magazine article by Scott
Dorsey.
My question is whether the so-called "Linkwitz mod" would
apply to this circuit. I'm guessing it would not, since
the source of the capsule's internal FET is made to float
above ground in the balanced scheme, but I'm not totally
sure of my conclusion. I have tried the balanced circuit
with the mod, but found it made little difference, except
that the case of the capsule needed a separate ground
connection. Any help on this would be much appreciated. Thanks.
Regards,
Joe Kramer

PS: Balanced output schemo similar to S. Dorsey's he

http://mp3forkidz.com/mic/phantxy.html

Linkwitz Mod he

http://www.linkwitzlab.com/images/graphics/microph1.gif


The Linkwitz mod looks great on paper, but has anybody actually tested its
effects in real-world high-SPL soundfields to see if it has any actual
beneficial effects?

I've played with some of this stuff. Yes, this mod does make a difference,
even at moderate (amplified) music levels distortion is reduced. At loud
levels (rock shows) it is really necessary to avoid distortion.

The basic idea is to make sure the FET operates as a "source follower", that
is, there is some kind of load resistor between the source and ground. This
can be done by:
1) linkwitz's mod
2) just putting a resistor there and running with a "standard" 9v battery box
(some signal is lost on the source resistor, but it still works)
3) running with three wires (+9v to the drain, 0v on ground, and taking
and audio signal from the source.

If you look at the schematic of most professional mics, you'll see a source
resistor of some form. For example, Audio Technica power modules use a 5.1k
source resistor and approx 3.0v to power the FET.

Many lav mics have the option to run either "2-wire" (without a source
resistor) or "3-wire" (with a load resistor).

I've also seen the source resistor replaced with a FET acting as a *constant
current source*. For example, AKG mics use this.

Lots of details can be found on the "Micbuilders" section at "Yahoo Groups".

Richard

[Arny Krueger]

wrote in message

"Arny Krueger" writes:

"Joe Kramer" wrote in message

Hi Friends,

I have built several mics based on Panasonic electret
elements and the electronically balanced output circuit
I
got from the old Recording Magazine article by Scott
Dorsey.
My question is whether the so-called "Linkwitz mod"
would
apply to this circuit. I'm guessing it would not, since
the source of the capsule's internal FET is made to
float
above ground in the balanced scheme, but I'm not totally
sure of my conclusion. I have tried the balanced
circuit
with the mod, but found it made little difference,
except
that the case of the capsule needed a separate ground
connection. Any help on this would be much
appreciated. Thanks. Regards,
Joe Kramer

PS: Balanced output schemo similar to S. Dorsey's he

http://mp3forkidz.com/mic/phantxy.html

Linkwitz Mod he


http://www.linkwitzlab.com/images/graphics/microph1.gif


The Linkwitz mod looks great on paper, but has anybody
actually tested its effects in real-world high-SPL
soundfields to see if it has any actual beneficial
effects?

I've played with some of this stuff. Yes, this mod does
make a difference, even at moderate (amplified) music
levels distortion is reduced. At loud levels (rock
shows) it is really necessary to avoid distortion.

The basic idea is to make sure the FET operates as a
"source follower", that is, there is some kind of load
resistor between the source and ground. This can be done
by: 1) linkwitz's mod
2) just putting a resistor there and running with a
"standard" 9v battery box (some signal is lost on the
source resistor, but it still works) 3) running with
three wires (+9v to the drain, 0v on ground, and taking
and audio signal from the source.

If you look at the schematic of most professional mics,
you'll see a source resistor of some form. For example,
Audio Technica power modules use a 5.1k source resistor
and approx 3.0v to power the FET.

Many lav mics have the option to run either "2-wire"
(without a source resistor) or "3-wire" (with a load
resistor).

I've also seen the source resistor replaced with a FET
acting as a *constant current source*. For example, AKG
mics use this.

Lots of details can be found on the "Micbuilders" section
at "Yahoo Groups".

Reading between the technical trivia which is pretty obvious and that I
already know, your answer must be that no, you have no practical tests that
conclusively show an advantage for this proposed modification.

[Richard Crowley]

"Arny Krueger" wrote ....
Reading between the technical trivia which is pretty obvious and that I
already know, your answer must be that no, you have no practical tests
that conclusively show an advantage for this proposed modification.

OTOH, if you have read any of Linkwitz's website you will
discover that this is not just some crack-head "taper" doing
random Frankenstein mutations to audio hardware.
http://www.linkwitzlab.com/links.htm Recommended.

[Joe Kramer]

That's not a balanced connection. That's a 'computer mic' type
connection.

Why do you want to make some kind of 'hybrid' ?

Right. The balanced output schemo similar to S. Dorsey's he

http://mp3forkidz.com/mic/phantxy.html

Don't want no hybrid, want/have a balanced, phantom-powered mic.

I believe you are talking about cutting the connection between the case
of the microphone and the normally-grounded FET pin of the microphone,
and adding a resistor so that the FET is floating above ground by a
couple volts.

You should be able to do this in conjunction with the balanced circuit,
BUT you need to forget about the system ground.

This makes sense. I've never connected the system ground (zero volts)
to the case when making these mics, and always make sure the case is
insulated from the body. But it's still a question of whether any of
this is necessary for the balanced version of the mic. . . .

The Linkwitz mod looks great on paper, but has anybody actually tested its
effects in real-world high-SPL soundfields to see if it has any actual
beneficial effects?

I haven't, but I'm sure somebody has, such as Mr. Linkwitz. However, he
doesn't provide charts/graphs as far as I can find. Lots of info via
Google. FWIW, I've yet to come across anything contradicting that it's
effective for improving the SPL capability of the mic.

The basic idea is to make sure the FET operates as a "source follower", that
is, there is some kind of load resistor between the source and ground. This
can be done by:
1) linkwitz's mod
2) just putting a resistor there and running with a "standard" 9v battery box
(some signal is lost on the source resistor, but it still works)
3) running with three wires (+9v to the drain, 0v on ground, and taking
and audio signal from the source.

Right. My question is whether any of this is needed for the balanced
configuration, since the FET is run as a phase-splitter, with equal
resistances at drain and source. It SEEMS to me the problem would be
addressed in that situation, but I'm still looking for certainty.
Thanks for any help on this.

Regards,
Joe

[Arny Krueger]

"Richard Crowley" wrote in message

"Arny Krueger" wrote ....
Reading between the technical trivia which is pretty
obvious and that I already know, your answer must be
that no, you have no practical tests that conclusively
show an advantage for this proposed modification.

OTOH, if you have read any of Linkwitz's website you will
discover that this is not just some crack-head "taper"
doing random Frankenstein mutations to audio hardware.

I know that, but I've heard some of his speaker designs. Nobody is perfect.


http://www.linkwitzlab.com/links.htm Recommended.

Yes, informative.

[[email protected]]

Joe Kramer writes:

That's not a balanced connection. That's a 'computer mic' type
connection.
Why do you want to make some kind of 'hybrid' ?

Right. The balanced output schemo similar to S. Dorsey's he

http://mp3forkidz.com/mic/phantxy.html

Don't want no hybrid, want/have a balanced, phantom-powered mic.

I believe you are talking about cutting the connection between the case
of the microphone and the normally-grounded FET pin of the microphone,
and adding a resistor so that the FET is floating above ground by a
couple volts.

You should be able to do this in conjunction with the balanced circuit,
BUT you need to forget about the system ground.

This makes sense. I've never connected the system ground (zero volts) to the
case when making these mics, and always make sure the case is insulated from
the body. But it's still a question of whether any of this is necessary for
the balanced version of the mic. . . .

The Linkwitz mod looks great on paper, but has anybody actually tested its
effects in real-world high-SPL soundfields to see if it has any actual
beneficial effects?

I haven't, but I'm sure somebody has, such as Mr. Linkwitz. However, he
doesn't provide charts/graphs as far as I can find. Lots of info via Google.
FWIW, I've yet to come across anything contradicting that it's effective for
improving the SPL capability of the mic.

The basic idea is to make sure the FET operates as a "source follower", that
is, there is some kind of load resistor between the source and ground. This
can be done by:
1) linkwitz's mod
2) just putting a resistor there and running with a "standard" 9v battery box
(some signal is lost on the source resistor, but it still works)
3) running with three wires (+9v to the drain, 0v on ground, and taking
and audio signal from the source.

Right. My question is whether any of this is needed for the balanced
configuration, since the FET is run as a phase-splitter, with equal
resistances at drain and source. It SEEMS to me the problem would be
addressed in that situation, but I'm still looking for certainty. Thanks for
any help on this.

Regards,
Joe

I'm pretty sure the problem is already solved if the FET has resistors on both
the source and drain.

Distortion arises in 2-wire designs because there is no source resistor. The
FET operates as an amplifier, but with nonlinear response, hence distortion.
When a source resistor is added the FET operates as a "follower", ie., gain =
1. This is analagous to a standard transistor (BJT) run as an "emitter
follower".

To the other poster (Dorsey?), yes these are obvious electronics facts, but
there are *some* people out there who don't know this stuff, including many
vendors of microphones (eg., lav mics). And please don't discount my
experience. I've tried with and without a source resistor and yes, there is
noticeable distortion with the 2-wire mode. I have not used test equipment to
measure it, though.

Richard

PS: here is a link to a Sennheiser document describing 2-wire and 3-wire mics. I couldn't find the Web URL, so I posted myself:
www.cs.uwaterloo.ca/~mannr/Export/mke2wiring.pdf

[Richard Crowley]

wrote ...

PS: here is a link to a Sennheiser document describing 2-wire
and 3-wire mics. I couldn't find the Web URL, so I posted myself:
www.cs.uwaterloo.ca/~mannr/Export/mke2wiring.pdf

That page shows nothing but different ways of connecting a "3-wire"
mic element. In a "2-wire" element one side of the transistor is
hard-wired to ground. That is why you cut the PC-board trace on
the back.

The document shows the "Red" and "Blue" as going to the source
and drain terminals on the FET. A common 2-wire electret mic
element has the source terminal of the FET hard-wired to ground.

[Joe Kramer]

wrote:

I'm pretty sure the problem is already solved if the FET has resistors on both
the source and drain.

Thanks, I'm pretty sure it is too. At any rate, the mics I've been
building with the balanced circuit don't exhibit obvious distortion 10"
from a bass cab or in a room with a drum kit. But I've yet to use them
close to a snare or kick drum. . . .

The basic idea is to make sure the FET operates as a "source follower", that
is, there is some kind of load resistor between the source and ground. This
can be done by:
1) linkwitz's mod
2) just putting a resistor there and running with a "standard" 9v battery box
(some signal is lost on the source resistor, but it still works)
3) running with three wires (+9v to the drain, 0v on ground, and taking
and audio signal from the source.

Seems to me method two would be the best all-round option, since no
messy trace-cutting and tricky grounding. I'll have to try this with a
small unblanced mic I built for use with a portable cassette recorder.
Not that distortion is much of a concern in that instance. In fact, a
little FET squashing might even be a good thing in that particular
application. . . .

Regards,
Joe

[[email protected]]

"Richard Crowley" writes:

wrote ...

PS: here is a link to a Sennheiser document describing 2-wire
and 3-wire mics. I couldn't find the Web URL, so I posted myself:
www.cs.uwaterloo.ca/~mannr/Export/mke2wiring.pdf

That page shows nothing but different ways of connecting a "3-wire"
mic element. In a "2-wire" element one side of the transistor is
hard-wired to ground. That is why you cut the PC-board trace on
the back.

The document shows the "Red" and "Blue" as going to the source
and drain terminals on the FET. A common 2-wire electret mic
element has the source terminal of the FET hard-wired to ground.

Yeah, I'm just showing an "official" document with the two powering options
listed. That's all.

Richard

[[email protected]]

On Sep 27, 9:35 am, "Arny Krueger" wrote:
wrote in message







"Arny Krueger" writes:

"Joe Kramer" wrote in message

Hi Friends,

I have built several mics based on Panasonic electret
elements and the electronically balanced output circuit
I
got from the old Recording Magazine article by Scott
Dorsey.
My question is whether the so-called "Linkwitz mod"
would
apply to this circuit. I'm guessing it would not, since
the source of the capsule's internal FET is made to
float
above ground in the balanced scheme, but I'm not totally
sure of my conclusion. I have tried the balanced
circuit
with the mod, but found it made little difference,
except
that the case of the capsule needed a separate ground
connection. Any help on this would be much
appreciated. Thanks. Regards,
Joe Kramer

PS: Balanced output schemo similar to S. Dorsey's he

http://mp3forkidz.com/mic/phantxy.html

Linkwitz Mod he

http://www.linkwitzlab.com/images/graphics/microph1.gif

The Linkwitz mod looks great on paper, but has anybody
actually tested its effects in real-world high-SPL
soundfields to see if it has any actual beneficial
effects?

I've played with some of this stuff. Yes, this mod does
make a difference, even at moderate (amplified) music
levels distortion is reduced. At loud levels (rock
shows) it is really necessary to avoid distortion.

The basic idea is to make sure the FET operates as a
"source follower", that is, there is some kind of load
resistor between the source and ground. This can be done
by: 1) linkwitz's mod
2) just putting a resistor there and running with a
"standard" 9v battery box (some signal is lost on the
source resistor, but it still works) 3) running with
three wires (+9v to the drain, 0v on ground, and taking
and audio signal from the source.
If you look at the schematic of most professional mics,
you'll see a source resistor of some form. For example,
Audio Technica power modules use a 5.1k source resistor
and approx 3.0v to power the FET.
Many lav mics have the option to run either "2-wire"
(without a source resistor) or "3-wire" (with a load
resistor).
I've also seen the source resistor replaced with a FET
acting as a *constant current source*. For example, AKG
mics use this.
Lots of details can be found on the "Micbuilders" section
at "Yahoo Groups".

Reading between the technical trivia which is pretty obvious and that I
already know, your answer must be that no, you have no practical tests that
conclusively show an advantage for this proposed modification.- Hide quoted text -

- Show quoted text -

I have, you can in fact get several VOLTS out of the mic at low
distortion. I'm surprised Arny, if one reads the literature on how
these cheap mics actually work, ie. the gate ends up biased on the
verge of conduction. The source follower connection bootstraps the
gate source junction and prevents the forward bias and clipping that
occurs in the normal connection.

[Arny Krueger]

wrote in message
ps.com

I have, you can in fact get several VOLTS out of the mic
at low distortion.

And your measured results for both methodologies, holding all other
parameters constant are?

I'm surprised Arny, if one reads the
literature on how these cheap mics actually work, ie. the
gate ends up biased on the verge of conduction. The
source follower connection bootstraps the gate source
junction and prevents the forward bias and clipping that
occurs in the normal connection.

If it was that easy, why isn't it done in the production devices?

[Scott Dorsey]

Arny Krueger wrote:
wrote in message

I'm surprised Arny, if one reads the
literature on how these cheap mics actually work, ie. the
gate ends up biased on the verge of conduction. The
source follower connection bootstraps the gate source
junction and prevents the forward bias and clipping that
occurs in the normal connection.

If it was that easy, why isn't it done in the production devices?

Because it costs additional money. Panasonic DOES make a production
capsule with three leads, for precisely this application. Digi-Key,
however, does not stock it, because it costs six cents more than the
more common 2-lead variant.

Digi-Key DOES stock some Knowles capsules designed this way, though.
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."

[[email protected]]

On Sep 28, 2:34 pm, "Arny Krueger" wrote:
wrote in message

ps.com

I have, you can in fact get several VOLTS out of the mic
at low distortion.

And your measured results for both methodologies, holding all other
parameters constant are?

I'm surprised Arny, if one reads the
literature on how these cheap mics actually work, ie. the
gate ends up biased on the verge of conduction. The
source follower connection bootstraps the gate source
junction and prevents the forward bias and clipping that
occurs in the normal connection.

If it was that easy, why isn't it done in the production devices?

There are results posted in the files section at the micbuilders
yahoo group. The source follower connection (as others have noted)
has only a gain of one. Actually these FETs are very low Idss so
there
is a little loss with a source resistor. For computer mics the
distortion
is not an issue and the loss in gain is.

BTW, I've worked as an EE for 33 years and have access to whatever
test gear I need. I've met Mr. Linkwitz he is also a very accomplished
EE.
I consider these issues obvious with any knowledge and thought of what
is involved.

[Arny Krueger]

wrote in message
oups.com
On Sep 28, 2:34 pm, "Arny Krueger"
wrote:
wrote in message

ps.com

I have, you can in fact get several VOLTS out of the mic
at low distortion.

And your measured results for both methodologies,
holding all other parameters constant are?

I'm surprised Arny, if one reads the
literature on how these cheap mics actually work, ie.
the gate ends up biased on the verge of conduction. The
source follower connection bootstraps the gate source
junction and prevents the forward bias and clipping that
occurs in the normal connection.

If it was that easy, why isn't it done in the production
devices?

There are results posted in the files section at the
micbuilders yahoo group. The source follower connection
(as others have noted) has only a gain of one. Actually
these FETs are very low Idss so there
is a little loss with a source resistor. For computer
mics the distortion
is not an issue and the loss in gain is.

BTW, I've worked as an EE for 33 years and have access to
whatever test gear I need. I've met Mr. Linkwitz he is
also a very accomplished EE.

I have no problematical doubts about Mr. Linkwitz, but I also know that he
is mortal and therefore capable of being less-than-perfect on occasion.

I consider these issues obvious with any knowledge and
thought of what is involved.

In the 52 years I've been involved with audio, I've seen lots of "obvious
improvments" that bore no reliably perceptible fruit. Note that the exact
same kinds of proof by means of credentials are offered by people who
believe in all sorts of audio magic, such as studio and home audio cables
with low skin effect.

[[email protected]]

On Sep 28, 3:13 pm, "Arny Krueger" wrote:
wrote in message

oups.com





On Sep 28, 2:34 pm, "Arny Krueger"
wrote:
wrote in message

oups.com

I have, you can in fact get several VOLTS out of the mic
at low distortion.

And your measured results for both methodologies,
holding all other parameters constant are?

I'm surprised Arny, if one reads the
literature on how these cheap mics actually work, ie.
the gate ends up biased on the verge of conduction. The
source follower connection bootstraps the gate source
junction and prevents the forward bias and clipping that
occurs in the normal connection.

If it was that easy, why isn't it done in the production
devices?

There are results posted in the files section at the
micbuilders yahoo group. The source follower connection
(as others have noted) has only a gain of one. Actually
these FETs are very low Idss so there
is a little loss with a source resistor. For computer
mics the distortion
is not an issue and the loss in gain is.

BTW, I've worked as an EE for 33 years and have access to
whatever test gear I need. I've met Mr. Linkwitz he is
also a very accomplished EE.

I have no problematical doubts about Mr. Linkwitz, but I also know that he
is mortal and therefore capable of being less-than-perfect on occasion.

I consider these issues obvious with any knowledge and
thought of what is involved.

In the 52 years I've been involved with audio, I've seen lots of "obvious
improvments" that bore no reliably perceptible fruit. Note that the exact
same kinds of proof by means of credentials are offered by people who
believe in all sorts of audio magic, such as studio and home audio cables
with low skin effect.- Hide quoted text -

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Arny, maybe it's just better to drop it. This is not an issue of a
"tweek".
I think you just knee-jerk responded like this was another green pen
around the CD. Mr Linkwitz has enough credibility that he is owed at
least a couple of minutes of homework. If you actually looked at his
write up the issue is pathilogical, a common source amplifier has a
couple of hundred milli-Volts before it HARD CLIPS. The source
follower connection can have 5 Volts p-p of reasonabley linear
response.
The point was to make very high SPL speaker measurements, the sonic
qualities of each connection in the small signal regime are never
mentioned. One connection works and the other simply does not.