John Curl's Blowtorch preamplifier part II - Page 1315 - diyAudio
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Old 29th June 2011, 06:39 PM   #13141
Previously: Kuei Yang Wang
 
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Hi,

Quote:
Originally Posted by Bonsai View Post
Which reminded me of Zane Johnson's (Audio Research) claim in an article I read that tubes were demonstrably better than solid state. So I searched on the web and found a site this had circuit diagrams of his stuff and one of the highly acclaimed preamps used a cheap Dallas solid-state volume control (32 step IIRC and about $2 in low volumes) married to a simple tube amplifier stage.
Actually, you need to look at MK II version (I think you where looking at the LS-25 schematic at ARCDB.WS). Current ARC stuff seems mostly J-Fets for gain, 6N30PE Tubes as cathode followers on the output. Maybe the wrong way around if you ask me, current CJ products do it the other way tube gain, fet buffer.

The Dallas/Maxim digitally controlled pots ARC uses are 128 step btw, appx. log law. I have tried them and correctly applied (there are one or two crucial tricks, miss them and the results suck) they are among the better digital attenuators. I am familiar with most of them BTW and would not use most.

Sadly Maxim has marked them NRND and Lifetime Buy, so one will have to find something else...

Ciao T
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Old 29th June 2011, 06:41 PM   #13142
SY is offline SY  United States
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Quote:
Originally Posted by john curl View Post
I bet that your phono stage sounds very, very, good.
People who have used it have made very kind comments. As you know, it's not exactly universal in application, so no danger of me ever trying to compete with you...
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Old 29th June 2011, 07:22 PM   #13143
wahab is offline wahab  Algeria
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Quote:
Originally Posted by Bonsai View Post

Conclusion (this is but one example, granted, but there are others): the statement that feedback amplifiers, or op amp based products do not perform as well, or sound as good, as discrete and/ZGF systems is incorrect, or at best, not proven.
Quote:
Originally Posted by jacco vermeulen View Post
Conclusion 2 : neither is the reverse.

Solid state amplifiers with GNFB are PROVED as being better than either
tubes amps or SS fedbackless amps.

The ones that contest such scientifically established constatation
always rely on unscientific discourse , going as far as pretending that
their ears are better suited to measure the distorsions of an amplifier
than instrumentation apparatus that are capable of measuring imperfections
several orders of magnitudes below human ear discrimination capabilities.
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Old 30th June 2011, 08:16 AM   #13144
Previously: Kuei Yang Wang
 
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Hi,

Quote:
Originally Posted by wahab View Post
Solid state amplifiers with GNFB are PROVED as being better than either tubes amps or SS fedbackless amps.
First, better implies a metric to be used by which it is possible to define better/worse. It would be good if, instead of making UNPROVEN and UNSUPPORTED statements, you could state the metrics used.

Second, in order to claim something is "better" one would probably have to prove that it is better for the intended purpose.

Amplifiers in Audio are intended explicitly for the reproduction of Speech and Music, so you need to provide proof that your selected metrics reliably correlate with a greater utility for the stated purpose.

Unless all these are presented you are merely making a statement that is not supported by fact.

It is in fact a direct inversion of the equally unsupported statement "Tubes sound better" or "Zero feedback sounds better".

However, there are very serious academic tests that show at least some support for for the "tubes/ZGNFB better" position that I am aware of, though they are usually not cited by the proponents of "Tubes/ZGNFB".

So, care to provide some evidence?

Maybe then I can then be arsed to provide some for the contrary position, but then again, maybe instead I'll take the advise of my teacher instead...

Quote:
Originally Posted by wahab View Post
The ones that contest such scientifically established constatation
Calling something "scientifically self-evident" does not make it so. Where is your evidence?

Quote:
Originally Posted by wahab View Post
always rely on unscientific discourse
As it seems do those who oppose them, based on your writing.

Quote:
Originally Posted by wahab View Post
going as far as pretending that their ears are better suited to measure the distorsions of an amplifier than instrumentation apparatus that are capable of measuring imperfections several orders of magnitudes below human ear discrimination capabilities.
So it is all about distortion?

You are trying to advance the old chetsnut that "lower distortion correlates with improved sound quality"? Would you care to provide evidence?

Ciao T
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Old 30th June 2011, 08:41 AM   #13145
Bonsai is offline Bonsai  Taiwan
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Torsten re your post on the ARC pre 's. Ok I stand corrected on the technical details of the volume pot. My point was ZJ was anti SS but used a solid state device for what most would consider a critical component.

That said, I have no beef when people claim a sounds better than b. I just don't accept that the difference is because opamps are used, GF or any of the other things that usually come up.

I am going to step out of this specific discussion now - positions are entrenched and I doubt either side will budge an inch.
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Old 30th June 2011, 09:14 AM   #13146
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Hi,

Quote:
Originally Posted by Bonsai View Post
Torsten re your post on the ARC pre 's. Ok I stand corrected on the technical details of the volume pot. My point was ZJ was anti SS but used a solid state device for what most would consider a critical component.
Well, he does not seem to have any problems with SS gain devices either (see ARC LS-25 MKII schematic below).

Click the image to open in full size.

Maybe he learned something new since that interview (charitable view) or he decided that commercially it was better, sound quality be damned (uncharitable view).

As I have used both open loop J-Fet gain stages and the DS-1666 used above I can attests that neither are reliable causes for bad sound.

Quote:
Originally Posted by Bonsai View Post
That said, I have no beef when people claim a sounds better than b. I just don't accept that the difference is because opamps are used, GF or any of the other things that usually come up.
Well, I think it may be that statements are not well qualified. For example, GNFB alone is not is a reliable cause for bad sound, however, they way it was commonly used in the 70's and 80's (and still is used most often) it can very well be.

Equally, Op-Amp'd alone do not assure bad sound, however many of those supposedly specifically designed for Audio have pretty poor subjective and objective performance (I find I BY FAR prefer video Op-Amp's for audio) and often the application is questionable, so that again we get many cases where "op-amp = bad sound".

It is tempting and easy to generalise from these frequent but isolated cases...

Quote:
Originally Posted by Bonsai View Post
I am going to step out of this specific discussion now - positions are entrenched and I doubt either side will budge an inch.
I can assure you that they will not budge. Each side feels it is reasonable and has good points.

What I do notice, we never get massive and extensive threads trying to copy generic Op-Amp preamps or boring generica Poweramp's, no matter how low the THD.

In fact, I rarely notice massive threads about "objectivist designed" HiFi, suggesting that either these designs not excite people intellectually, sonically or both.

Ciao T

Last edited by ThorstenL; 30th June 2011 at 09:20 AM.
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Old 30th June 2011, 09:20 AM   #13147
gk7 is offline gk7
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Quote:
Originally Posted by wahab View Post
Solid state amplifiers with GNFB are PROVED as being better than either
tubes amps or SS fedbackless amps.

The ones that contest such scientifically established constatation
always rely on unscientific discourse , going as far as pretending that
their ears are better suited to measure the distorsions of an amplifier
than instrumentation apparatus that are capable of measuring imperfections
several orders of magnitudes below human ear discrimination capabilities.
Seems to me you have no clue how the ear / brain combination works.
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Old 30th June 2011, 09:35 AM   #13148
EUVL is offline EUVL  Europe
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Thorsten,

Have you tried others from Maxim, such DS1867 ?


Patrick
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Old 30th June 2011, 09:37 AM   #13149
wahab is offline wahab  Algeria
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Quote:
Originally Posted by gk7 View Post
Seems to me you have no clue how the ear / brain combination works.
It works in a way that scientific evidence can be denied by the set
ear/brain that, by the definition, is influenced by emotions, not scientific
computing and deductions.
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Old 30th June 2011, 09:45 AM   #13150
wahab is offline wahab  Algeria
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Quote:
Originally Posted by ThorstenL View Post

First, better implies a metric to be used by which it is possible to define better/worse. It would be good if, instead of making UNPROVEN and UNSUPPORTED statements, you could state the metrics used.
.

So, care to provide some evidence?
We have technically established metric using the usual apparatus,
the very same whose results are never denied when computing a device
caracteristic.

By all possible measurements, GNFB amps have better caracteristics
in respect of accuracy of the amplified signal.

The only response of those contradicting such evidences is to propose
to remove any scientificaly computed number and rely solely on the ears,
since they know that these latters are not accurate enough to the point
that a distorted signal can be confused as "better sounding".
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