THD claims of audio signal generators

[John Larkin]

On Wed, 4 Jan 2006 09:43:45 -0600, "Tim Williams"
<tmoranwms@charter.net> wrote:

"Arny Krueger" <arnyk@hotpop.com> wrote in message
news:qKKdnaxtnbfeVSbenZ2dnUVZ_s-dnZ2d@comcast.com...
Tubes have always been proprietary parts. OK, you HP 200C has say a
6SN7 in it. Which manufacturer's 6SN7 is the right one to use?

Uh..!? Tubes from different manufacturers are _massively_ better matched
than any two transistors or ICs from the _same batch_!

Tim

That's totally backwards.

If you're talking about transconductance, *any* two small-signal
silicon transistors, even of different part numbers, will be better
matched than 99% of tube "matched pairs."

And after three months of use, the tubes will have drifted all over
the place, but the transistors won't.

And if you're talking differential offset voltage or drift of same,
the transistors beat the tubes by volts.

And you can't compare beta, bacause tubes don't have it.

John

 

[Tim Williams]

"John Larkin" <jjlarkin@highNOTlandTHIStechnologyPART.com> wrote in message
news:eisnr1pd1g8uv2jph8t5f7tiehiffssmsf@4ax.com...

If you're talking about transconductance,

Ya, because they have that fun little exponential Vbe curve. Beta is to
transistors what Gm is to tubes and FETs, and you know it...

Tim

--
Deep Fryer: a very philosophical monk.
Website: http://webpages.charter.net/dawill/tmoranwms

 

[Don Pearce]

On Wed, 4 Jan 2006 10:37:27 -0600, "Tim Williams"
<tmoranwms@charter.net> wrote:

"John Larkin" <jjlarkin@highNOTlandTHIStechnologyPART.com> wrote in message
news:eisnr1pd1g8uv2jph8t5f7tiehiffssmsf@4ax.com...
If you're talking about transconductance,

Ya, because they have that fun little exponential Vbe curve. Beta is to
transistors what Gm is to tubes and FETs, and you know it...

Tim

What - I mean, WHAT?

d

Pearce Consulting
http://www.pearce.uk.com

 

[Arny Krueger]

"Tim Williams" <tmoranwms@charter.net> wrote in message
news:_RSuf.171$dj3.120@fe04.lga

"John Larkin"
jjlarkin@highNOTlandTHIStechnologyPART.com> wrote in
message
news:eisnr1pd1g8uv2jph8t5f7tiehiffssmsf@4ax.com...

If you're talking about transconductance,

Ya, because they have that fun little exponential Vbe
curve.

So far, so good.

Yes, and the Vbe curve relates very closely to the standard definition of
transconductance, right?

Beta is to transistors what Gm is to tubes and
FETs, and you know it...

Huh?

 

[John Larkin]

On Wed, 4 Jan 2006 10:37:27 -0600, "Tim Williams"
<tmoranwms@charter.net> wrote:

"John Larkin" <jjlarkin@highNOTlandTHIStechnologyPART.com> wrote in message
news:eisnr1pd1g8uv2jph8t5f7tiehiffssmsf@4ax.com...
If you're talking about transconductance,

Ya, because they have that fun little exponential Vbe curve. Beta is to
transistors what Gm is to tubes and FETs, and you know it...

Tim

No, transistor Gm is to tube Gm as...

Good transistor design is beta independent, as good tube design is
tolerant of variations in transfer curves, grid current, and
transconductance.

John

 

[Stewart Pinkerton]

On Wed, 4 Jan 2006 09:43:45 -0600, "Tim Williams"
<tmoranwms@charter.net> wrote:

"Arny Krueger" <arnyk@hotpop.com> wrote in message
news:qKKdnaxtnbfeVSbenZ2dnUVZ_s-dnZ2d@comcast.com...
Tubes have always been proprietary parts. OK, you HP 200C has say a
6SN7 in it. Which manufacturer's 6SN7 is the right one to use?

Uh..!? Tubes from different manufacturers are _massively_ better matched
than any two transistors or ICs from the _same batch_!

Utter bullshit. In any normal application, IC matching is vastly
superior to valve matching.
--

Stewart Pinkerton | Music is Art - Audio is Engineering

 

[Ted Edwards]

Tim Williams wrote:

Ya, because they have that fun little exponential Vbe curve. Beta is to
transistors what Gm is to tubes and FETs, and you know it...

I've seen your posts here and elsewhere. They all seem to be of similar
quality. I have been designing, building and _listening to_ audio
amplifiers for about 60 years and the plain fact is that tube amps just
don't do a good job especially at very low or very high frequencies.
Almost acceptable THD is possible at 1 KHz matbe even up to 5 or 10 but
then maybe you can't hear anything above that.

Ted

 

[Bret Ludwig]

Arny Krueger wrote:

elephantcelebes@yahoo.com> wrote in message
news:1136262642.278391.35950@g44g2000cwa.googlegroups.com


Today, for practically any purpose that I can imagine in
my home shop, the audio output on my PC sound card rules.

Most PC sound cards vastly outperform legacy audio signal generators, both
for low distortion and flatness. They also have excellent settling times.

A decent voltmeter tells me the output level.

The trick is finding an inexpensive one with good frequency response. My
best meters are Flukes (not cheap) or the ProTek 506 (flat enough but not
wonderful and still not exactly cheap).

No Arny, the trick is to ante up once and buy a good one from a first
or at least second tier manufacturer whose specs well eclipse the job
at hand. Second tier manufacturers are sometimes better because they
use off the shelf parts where Agilent and Tek used their fab
capabilities to make wonderful chips....that no longer exist. And they
are not making more.

If commodisumo PeeCee hardware were test grade National , Aeroflex,
Agilent and others would not be getting the hemmorhoid-splattering
prices they do for CompactPCI and VME/VXI hardware. A peecee is not a
core piece of test equipment. Yes you can do a few things with a sound
card, but a Audio Precision box is NOT a sound card in a fancy box.

 

[Bret Ludwig]

Ted Edwards wrote:

Tim Williams wrote:
Ya, because they have that fun little exponential Vbe curve. Beta is to
transistors what Gm is to tubes and FETs, and you know it...

I've seen your posts here and elsewhere. They all seem to be of similar
quality. I have been designing, building and _listening to_ audio
amplifiers for about 60 years and the plain fact is that tube amps just
don't do a good job especially at very low or very high frequencies.
Almost acceptable THD is possible at 1 KHz maybe even up to 5 or 10 but
then maybe you can't hear anything above that.

Bullshit on stilts. McIntosh, ARC, Julie Labs and many others have
made tube amps with THD and intermod specs comparable to any popular
solid state and bandwidth up to at least 25 or 30 kHz, surely you can't
hear above that. Tube amps do a good job from perhaps 16 Hz (they are
down some there usually) to 20-22 kHz (and if they are down a little
over 15 kHz that's OK as long as it is not too sudden a slope) and
because the type of distortioon differs. .1 THD is OK on tube amps
whereas .01 may NOT be on solid state. Subjectively tube amps of a
given specification often (not always) sound better than solid state
amps of better spec. Russ Hamm proved it in 1973 with his paper which
appeared in JAES and it has not been contradicted. Arny talks a lot but
he knows it's true and will be until they change the laws of physics.

We got Cal a copy of the book "An Evening with Marilyn" by Douglas
Kirkland for Christmas. There's a hi--fi system in the background in
the loft where the shoot takes place. (Looks like an Altec amp and a
big Altec bass driver-the horns are out of the picture. There's a big
dust cap-it's not a 604....but who would have cared?) You know when
Frank Sinatra, Arthur Miller, JFK, and DiMaggio were on top of THAT
situation the music was playing just fine with no silicon involved. You
know what? It still does. (The music. The people, they're dead.)

 

Bret Ludwig wrote:

Arny Krueger wrote:
snip
If you use them a lot, the tubes wear out.

This is why they still make'em.

There
are no proprietary parts that are likely to wear out with
normal use.

Tubes have always been proprietary parts. OK, you HP 200C has say a 6SN7 in
it. Which manufacturer's 6SN7 is the right one to use?
My experience is the box works with any of them. Probably one yields
best case distortion or dial tracking. I have never had it be an issue.

My experience with several dozen HP 200's does not match yours.
Yes, they all oscillate, but amplitude stability and phase noise is
tube dependent.

The tube-bigot lie here is that most ICs in good audio test equipment are
standard parts, or can be readily replaced with standard parts.

IIRC the 8903 has a proprietary diff amp that is close to unobtanium.

If you recall, the 8903 is a fairly rare beast in and of itself and
hardly
constitutes an example supporting your claim. I have an entire wall
of audio test equipment from HP, ST, Techron, GR, B&K, Leader,
and so on, and there's nary a proprietary IC in any one of them.

Now the exception is my old, trusty GR 1390B random noise
generator which uses a proprietary noise diode. if it goes, the
unit is worthless. WAIT! It's a vacuum tube, not an IC! Fancy that,
a proprietary, non-replaceable vacuum tube.

HP solid state RF gens use a lot of proprietary silicon-8640s

Lessee, HP 8640: signal generator with a range of 500 kHz to
500 MHz. Please explain how that is "audio test equipment."

 

[Bret Ludwig]

dpierce@cartchunk.org wrote:

<<snip>>

My experience with several dozen HP 200's does not match yours.
Yes, they all oscillate, but amplitude stability and phase noise is
tube dependent.

i have probably just been lucky. Also I pay little attention to the
dial markings, I use my freq counter to set frequency. And I don't use
them for scope cal, there are precision level gens that are used for
that.

The tube-bigot lie here is that most ICs in good audio test equipment are
standard parts, or can be readily replaced with standard parts.

IIRC the 8903 has a proprietary diff amp that is close to unobtanium.

If you recall, the 8903 is a fairly rare beast in and of itself

Oh no! They were sold by the truckload because they replaced the 339.
Then they went to *ucker in trade for....used 339s....because they
weren't. Potomac IIRC essentially cloned the 339, but in two boxes, a
gen and receive, and charged more for either than HP had for the 339.
So 8903s are common as sin. However, barring abuse, they run forever.

and

hardly
constitutes an example supporting your claim. I have an entire wall
of audio test equipment from HP, ST, Techron, GR, B&K, Leader,
and so on, and there's nary a proprietary IC in any one of them.

Now the exception is my old, trusty GR 1390B random noise
generator which uses a proprietary noise diode. if it goes, the
unit is worthless. WAIT! It's a vacuum tube, not an IC! Fancy that,
a proprietary, non-replaceable vacuum tube.

HP solid state RF gens use a lot of proprietary silicon-8640s

Lessee, HP 8640: signal generator with a range of 500 kHz to
500 MHz. Please explain how that is "audio test equipment."

Well, then I guess an FM tuner isn't an "audio unit".

 

[Pooh Bear]

Bret Ludwig wrote:

Subjectively tube amps of a
given specification often (not always) sound better than solid state
amps of better spec. Russ Hamm proved it in 1973 with his paper which
appeared in JAES and it has not been contradicted.

Not contradicted ? It's crock of bull. It was out of date in its methodology and
conclusions even before it was printed.

Graham

 

Bret Ludwig wrote:

dpierce@cartchunk.org wrote:

snip
My experience with several dozen HP 200's does not match yours.
Yes, they all oscillate, but amplitude stability and phase noise is
tube dependent.

i have probably just been lucky.

I would take it , then, that you have not seen more than maybe a
couple of these units, yes? So, you hardly speak from a position
of authority. Having run an electronics calibration lab, and seen
quite a few, I might huimbly suggest my experience trumps yours.

Also I pay little attention to the
dial markings, I use my freq counter to set frequency.

Fine, but that doesn't deal with drift, amplitude instability, and all
the rest.

And I don't use
them for scope cal, there are precision level gens that are used for
that.

And how many of them are solid state>

The tube-bigot lie here is that most ICs in good audio test equipment are
standard parts, or can be readily replaced with standard parts.

IIRC the 8903 has a proprietary diff amp that is close to unobtanium.

If you recall, the 8903 is a fairly rare beast in and of itself

Oh no! They were sold by the truckload because they replaced the 339.
Then they went to *ucker in trade for....used 339s....because they
weren't.

You obviously missed my point, or chose to completely dance
around it with irrelevancies. The 8903 is merely ONE example
of audio test equipment. It is not representative of the realm of
equipment as you might suggest it does. Besides, you have
already demonstrated pretty narrow experience with HP200's,
and you did qualify your claims on the 8903 with "IIR," yes?
SO you have yet to provide any substantiation to your claim.

Potomac IIRC essentially cloned the 339, but in two boxes, a
gen and receive, and charged more for either than HP had for the 339.

How in any way, shape or form is this at all relevant?

So 8903s are common as sin. However, barring abuse, they run forever.

Which seems to contradict you earlier point.

I have an entire wall
of audio test equipment from HP, ST, Techron, GR, B&K, Leader,
and so on, and there's nary a proprietary IC in any one of them.

A point you failed to address.

Now the exception is my old, trusty GR 1390B random noise
generator which uses a proprietary noise diode. if it goes, the
unit is worthless. WAIT! It's a vacuum tube, not an IC! Fancy that,
a proprietary, non-replaceable vacuum tube.

A point you failed to address.

I should also add that of all the equipment I have, the tube0based
stuff has been the most difficult to support, because it's becoming
increasingly difficult to find suitable tubes, any ol' fire bottle just
won't do. But , even though the tubes ARE easy to extract, they
WILL have to be replaced at some point, absolute guarantee.

Whether or not any of the solid state units have proprietary parts
that will be hard to replace, I don't know: not a single one of them
has failed.

HP solid state RF gens use a lot of proprietary silicon-8640s

Lessee, HP 8640: signal generator with a range of 500 kHz to
500 MHz. Please explain how that is "audio test equipment."

Well, then I guess an FM tuner isn't an "audio unit".

Last time I checked, the part that an HP 8640 would test isn't.

 

[RapidRonnie]

Jim Thompson wrote:
<<snip>>

Uh..!? Tubes from different manufacturers are _massively_ better matched
than any two transistors or ICs from the _same batch_!

Tim

What a pile of nonsense!

I'm afraid it's true. Discrete power transistors vary much more than

tubes of a given type and manufacture run. That's why construction or
repair of high power solid state amps requires either factory-matched
sets or the use of a curve tracer to sort through piles of them.

Of course, the transistors come in N and P channel or NPN and PNP
types whereas tubes are not complementary. So it's apples vs. oranges.

Are apples or oranges better?

 

[RapidRonnie]

Pooh Bear wrote:

Bret Ludwig wrote:

Subjectively tube amps of a
given specification often (not always) sound better than solid state
amps of better spec. Russ Hamm proved it in 1973 with his paper which
appeared in JAES and it has not been contradicted.

Not contradicted ? It's crock of bull. It was out of date in its methodology and
conclusions even before it was printed.

It may or may not be a crock, but no one has submitted a rebutting
paper to the AES for consideration in 32 years. So I am inclined to
believe it myself.

 

[Arny Krueger]

"Bret Ludwig" <bretldwig@yahoo.com> wrote in message
news:1136412570.711284.174060@z14g2000cwz.googlegroups.com

Arny Krueger wrote:
elephantcelebes@yahoo.com> wrote in message
news:1136262642.278391.35950@g44g2000cwa.googlegroups.com


Today, for practically any purpose that I can imagine in
my home shop, the audio output on my PC sound card
rules.

Most PC sound cards vastly outperform legacy audio
signal generators, both for low distortion and flatness.
They also have excellent settling times.

A decent voltmeter tells me the output level.

The trick is finding an inexpensive one with good
frequency response. My best meters are Flukes (not
cheap) or the ProTek 506 (flat enough but not wonderful
and still not exactly cheap).

No Arny, the trick is to ante up once and buy a good one
from a first or at least second tier manufacturer whose
specs well eclipse the job at hand.

Given that I mentioned a first tier vendor (apparently you never heard of
Fluke, Brat) I've got your "buy a good one" covered. Given that I mentioned
ProTek (apparently you never heard of them, either) I've got the lower tiers
covered as well.

BTW Brat, for your future reference, here's some much-needed info for you
about who Fluke is:

http://www.fluke.com/

 

[Arny Krueger]

"RapidRonnie" <rapidronnie@cbgb.net> wrote in message
news:1136425034.690014.67700@g14g2000cwa.googlegroups.com

Jim Thompson wrote:
snip
Uh..!? Tubes from different manufacturers are
_massively_ better matched than any two transistors or
ICs from the _same batch_!

Tim

What a pile of nonsense!

I'm afraid it's true. Discrete power transistors vary
much more than tubes of a given type and manufacture run.

Not in terms of parameters that matter.

That's why construction or repair of high power solid
state amps requires either factory-matched sets or the
use of a curve tracer to sort through piles of them.

That would be a misapprehension on your part, Ronnie.

 

[Arny Krueger]

"Bret Ludwig" <bretldwig@yahoo.com> wrote in message
news:1136415565.381603.82320@o13g2000cwo.googlegroups.com

Ted Edwards wrote:
Tim Williams wrote:
Ya, because they have that fun little exponential Vbe
curve. Beta is to transistors what Gm is to tubes and
FETs, and you know it...

I've seen your posts here and elsewhere. They all seem
to be of similar quality. I have been designing,
building and _listening to_ audio amplifiers for about
60 years and the plain fact is that tube amps just don't
do a good job especially at very low or very high
frequencies. Almost acceptable THD is possible at 1 KHz
maybe even up to 5 or 10 but then maybe you can't hear
anything above that.

Bullshit on stilts. McIntosh,

Prove it:

http://www.mcintoshlabs.com/data/compare/ampcomp3.04web.pdf

MC275, their only tubed amp - rated THD = 0.5% out of the running

ARC,

http://www.audioresearch.com/300.2.html

1% THD

http://www.audioresearch.com/VM220.html
http://www.audioresearch.com/VS110.html
http://www.audioresearch.com/vt100new.html

0.5% THD

http://www.audioresearch.com/VS55.html
http://www.audioresearch.com/VSi55.html

1% THD


Julie Labs

No evidence on web

and many
others have made tube amps with THD and intermod specs
comparable to any popular solid state and bandwidth up to
at least 25 or 30 kHz, surely you can't hear above that.

Only contradictory evidence can be found.

 

[Arny Krueger]

"RapidRonnie" <rapidronnie@cbgb.net> wrote in message
news:1136425244.638052.39920@o13g2000cwo.googlegroups.com

Pooh Bear wrote:
Bret Ludwig wrote:

Subjectively tube amps of a
given specification often (not always) sound better
than solid state amps of better spec. Russ Hamm proved
it in 1973 with his paper which appeared in JAES and it
has not been contradicted.

Not contradicted ? It's crock of bull. It was out of
date in its methodology and conclusions even before it
was printed.

It may or may not be a crock, but no one has submitted a
rebutting paper to the AES for consideration in 32 years.

There's no need to, just like all the other JAES papers that now contain
obsolete information.

 

[Arny Krueger]

"Bret Ludwig" <bretldwig@yahoo.com> wrote in message
news:1136412940.089566.232810@g43g2000cwa.googlegroups.com

Arny Krueger wrote:
snip
If you use them a lot, the tubes wear out.

This is why they still make'em.

There
are no proprietary parts that are likely to wear out
with normal use.

Tubes have always been proprietary parts. OK, you HP
200C has say a 6SN7 in it. Which manufacturer's 6SN7 is
the right one to use?

My experience is the box works with any of them.
Probably one yields best case distortion or dial
tracking. I have never had it be an issue.


The tube-bigot lie here is that most ICs in good audio
test equipment are standard parts, or can be readily
replaced with standard parts.

IIRC the 8903 has a proprietary diff amp that is close to
unobtanium.

Take it up with the manufacturer - its gratuitous.

In fact audio generators with rediculously low residiuals have been made
using nothing more exotic than NE 5532s.