Re: Do all amplifiers sound the same?

On Sun, 11 May 2008 08:04:49 -0700, Arny Krueger wrote
(in article <g071uh0mk8@[EMAIL PROTECTED]
>):

> "Peter Elem" <pelem@[EMAIL PROTECTED]
> wrote in message
> news:g004io0mgk@[EMAIL PROTECTED]
>> Some manufactorers admit that they Color or "voice" their
>> amplifiers. Audio Research does and of course there are
>> the Carver solid state amps that were supposedly voiced
>> like tube amplifiers.
> 
> The fallacy here is the idea that there is some combination of audio 
> colorations that are characteristic of tubed (or SS) power amplifiers.
> 
> There are some very high quality tubed amplifiers that are sonically 
> transparent - they will pass an audio signal into a loudspeaker load
without 
> any audible changes.
> 
> Most tubed audio equipment will fail straight-wire bypass tests, 
> particularly with tough loudspeaker loads. The root cause is their
typically 
> high output impedance, especially at low frequencies.
> 
> Some tubed amplifiers have design features that seem to be designed to 
> product an amplifier that is not sonically transparent, such as
single-end 
> output stages and absence of or severe reduction of inverse feedback.
> 
> The bottom line is that many of the audible alterations caused by tubed 
> amplifiers have varied and complex sources, and may be strongly
dependent on 
> the particular speaker being driven.
> 
> While duplicating the sound of a certain tubed amplifier may be
possible, it 
> would only be a certain tubed amplifier that would be duplicated, and
not 
> all or even most tubed amplfiiers that would be duplicated.
> 
> In the professional audio world there are devices that have
user-selectable 
> features that are designed to duplicate the sonic properties of certain 
> amplifier/loudspeaker combinations that are sold as a single unit. This
is 
> at least a credible claim, as compared to the claim that a certain SS
amp is 
> voiced to sound like tubed amplifiers. 
> 

Carver used test equipment in his demonstrations to make his amp sound
like a 
specific tube amp, not tube amps in general. In the demo I was party to,
he 
made his amp sound like a big conrad johnson amp (I don't remember the
model 
number). He said that he could do that for any amp, but I only know about
the 
one I heard. I think John Atkinson was at a similar Carver demonstration, 
maybe he can shed some light upon what Carver actually adjusted, and how
is 
"nulling" procedure worked. I don't really remember the details (we're 
talking 20 years ago, here).