Chelvam wrote:

"Pooh Bear" wrote in message
...
Chelvam wrote:

These specs belong to two different Valve Amplifiers. Which one can be
considered to be better?

snip specs for brevity

Since the specs for product X and product Y specify entirely different
parameters, there is no meaningful comparison that can be made on this
information alone, let alone decisions about which is *better*.


Yes, that's why I posted the question. The product x was a $25,000 VA-1 of
www.cadenceaudio.com and the product Y is WAVAC's 833.

I would be deeply sceptical of any audio amplifier product with a price of
$25,000. It's simply pandering to 'boutique audio' marketing that claims
*magical* properties for their product only of course ! And pandering to those
with deep pockets too of course !

What I don't get is the specifications are not uniform and they give
different parameters for different model.

I am most involved with the professional audio trade. Most manufacturers in that
realm have no difficulty presenting full and meaningful specifications that are
easily compared.

A manufacturer in the hi-fi realm who chooses to avoid quoting recognised
technical measurements should be questioned for their reasoning IMHO.

You may choose to let the manufacturer's reluctance to quote full and meaningful
figures influence your estimation of them.


And I have one more manufacturer
who says "There is a difference between TAC 34 , TAC 88 , TAC 834 , Magma ,
Audio Institute and our MODIFIED IN ENGLAND valve amplifier ! ( Unscrupulous
dealers who tell you that they are the same are liars , and breaking the law
of "Trade Description Act" ! )" . This the boldest statement that I have
heard so far. http://www.affordablevalvecompany.com/index.html but somehow
I can't find the specs in there.

I believe I saw this recently on ebay.co.uk or a link from there too. Seems to
apply to imported valve amps of Chinese manufacture.


Surely there must be some standard set by AES or other audio engineering
organisation for amplifiers.

I don't think the AES has ever felt the need to intervene ! The AES does however
publish recommended test *techniques / methods*. I assume that they expect that
those test figures might then be published ! They can't force ppl to however.
Any competent manufacturer knows what scecifications are routinely published. If
they choose not to publish recognised technical specs - then caveat emptor.
WAVEC's 'spec' was deeply lacking in meaningful detail.

Specs can only give you a portion of the picture however. The distortion specs
that are typically published for example ( usually THD - total harmonic
distortion ) give insufficient information about the distortion spectrum to make
a truly informed choice between ( especially ) those products using different
circuit toplogies. E.g. Valve / solid state : class A / class AB : linear / PWM
( digital ) to name just a few possibilities.

In comparison a signal to noise ratio is quite meaningful ( the bigger the
better ). Similarly, frequency response should be 'flat' ( +/- the least number
of dB - ideally 0.5 for example ) over the whole of - or more than the entire
audio spectrum to avoid obvious signal colouration. In practice, a flat
frequency response is pretty easy to acheive these days.


Graham