bob marcus

One would be wrong, then. "Nominally competent" means competent to drive a
particular load--in the case of audio, the ability to drive a particular set
of speakers in a particular room at a particular loudness level without
producing audible distortion.

Now, if we know all those things (speakers, room, loudness), presumably some
engineer could give you a good idea of how big an amp you'd need. But
"nominally competent" is not some abstract standard that amps either meet or
don't meet in all cases. A 20-watt amp might be quite competent driving a
little ported speaker and quite incompetent pushing a big, sealed subwoofer.


If they all sounded different, no more than one was NC! Odds are the only
reason they all "sounded" different was because they all looked different.

Are you sure he wasn't just telling you that the information you want can't
be found on spec sheets?

Available (objective) evidence suggests that most modern solid state amps are.


The information you want can't be found there, either.

Look, the task isn't nearly as difficult as you make it out to be. Plug it
in, and see if it works. By which I mean, take the amp home, insert it in
your system, put on a big orchestral recording, crank the volume up as high
as you'll ever want to crank it, and ask yourself, "Does this sound OK?" If
it does, the amp's competent.

bob

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wylie williams

That would be a helpful answer to some people, but I never had a system
that didn't sound "OK". What I have now is "Pretty Good", which is three
notches above "OK" on my personal scale. It may be foolish to seek to have
as close to "Wonderful" as I can afford, but I accept this character flaw in
myself (and others) and persist in it. I conditionally accept my CD,
turntable and cables as sufficient. Before I get too crazy on speakers I
would like to assure myself that the sound quality and power output of my
amplification are not a limiting factor. The question of how to determine
if an amp is "nominally competent" seems to be the first step. Once the NC
question is answered I can seek the answer to the question "how much power
is enough to be sure I am extracting all the performance from whatever
speaker I end up with". Any money I save by not overspending on the amp can
be applied to the speakers.
.. The audiophile press persists in saying that you can get better and
better sound in amps by spending more and more money. Many RAHE members say
that a nominally competent amp can be had for comparatively modest cost.
Having sold low fi to mid fi for many years I know that there are many low
priced amps that definitely sound worse than their higher priced brethren.
Unfortunately I have too little experience with high end to know where the
point of "nominal competence" begins.

It would be very helpful if this term "nominally competent" has a meaning
that is definable and usable.

Wylie Williams

bob marcus

In that case, you've never had an amp that wasn't nominally competent. Why
is this so hard for you to accept?

But whether or not your amp's power output is a limiting factor is
substantially dependent on your speakers (and your room, and how loud you
listen). You cannot answer that question before you've chosen your speakers.

No. Choosing your speakers is the first step.

Now I'm sure you don't get it. "Nominally competent" means, in essence, flat
frequency response and enough power. An amp isn't competent unless it can deliver enough power.

Indeed they do, and lots of audiophiles believe them. Others don't, however,
and have offered some very good technical reasons why not.

This is often true when you know what the pricetag says. ;-)

I'd bet if you went back and compared those amps without knowing which was
which, you'd be a lot less definite.

It has nothing whatsoever to do with price, for starters.


One more time: A nominally competent amplifier is one that delivers a signal
into a particular load (your speakers, your room, etc.) without audible
distortion--that is, with flat frequency response and minimal clipping.

Now, go out there and buy the best speakers you can afford.

bob

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harry lavo

Oh, it's definable.

If Stewart, Steven, Bob, or Tom can't hear a difference from their own amps
using dbt, then it's "nominally competent". If they do hear a difference,
it isn't.

Whether that's useful I leave up to you.

rbernst929

I'll try this one more time, for those of you in the "there is no difference"
school of amplifier design. Take one person's system at home. Replace just
the amplifier with different types. Listen. See if everyone agrees that the
resulting sound is identical, especially to the person's who owns and is
familiar with the system. If all amplifiers are "technically perfect" since
1950, there should be NO difference AT ALL in the sound. But, if there IS a
difference, whether it is qualifiable as to type (ie: more treble, less bass)
or whatever, then "all amplifiers sound the same" is wrong. -Bob Bernstein.

bob marcus

Who would that be?

No one's ever said that all amplifiers sound the same. Ever.

As for your little experiment, it's about as meaningful as pointing to the
sun rising in the east as proof that it revolves around the earth.

bob

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wylie williams

OK. I get it. If I don't hear any distortion it passes the test. Wow, I
had it all wrong. I thought that there was some objective verifiable
criteria. Now I can buy a $199 Kenwood receiver and be happy.
And all those kids who drive those boom cars have great equipment because
they don't hear any distortion.
This new subjective approach sounds great. Got to stop now; it's time to
got listen to some expensive cables.

Wylie Williams

wylie williams

I aplologize for my inept internet skills. Somehow on the post below I
seem to be replying to Bob Bernstein when I was replying to the Bob Marcus
post below. I also apololgize for the frivolus tone of my reply to Bob
Marcus, if not my dissatisfaction with the general idea that I got from his
post, which is that "plug it in and play it; if you don't hear distortion
it's as good as it gets". That sounds like a subjective answer, and was
asking for an objective answer.
Mind you, I have no objection to the subjective school of audiophilia,
as I have followed that path for years. But as RAHE has many committed and
persuasive adherents to the objective school I thought I would find out some
objective criteria for amp selection. But not too successfully. Noussaine,
for example, tells of his dozen or so amps that all sound the same to him.
I don't doubt that he ( as well as all the other adherents of the "if it's a
nominally competent amp it sounds like all the other nominally competent
amps" school ) has a great system and great ears, but that's no help to me.
I would like to find out the criteria for NC status. Mr. Marcus says "flat
frequency response and enough power" and "without audible distortion". I am
under the impression that flat frequency response is as common as dirt. As
far as "without audible distortion" goes I have considerable experience in
the mid-fi business and I know that the vast majority of healthy young males
with good hearing think anything that plays loud has "no audible
distortion". Or is it "no audible distortion as judged by a golden eared
listener"? Who certifies the goldenness of the ears? Certainly
professional audiophile reviewers would be the clear choice for experienced
golden ears, but they all say that even the best amps have very different
sounds. Perplexing!
Besides, if distortion is audible variation from the original sound
then then vast majority of reproduced sound I have heard in my life has been
audibly distorted. Sometimes more distorted, sometimes less, sometimes a few
moments of a convincing illusion, sometimes "euphonic coloration" (which I
definea s likeable distortion), and only occasionally apparently free of
distortion.
As for selecting the speaker first, that's an interesting thought.
And it's worth it's own thread. I thought I would try to settle the quality
issue first and deal with the quantity issue later. Besides, after selecting
a speaker I would have to choose an amp, so knowing the elusive criteria for
"nominally competent" would be the starting point, wouldn't it? Maybe I
have a better speaker than I know, but my amp is lacking.

Wylie Williams

In that case, you've never had an amp that wasn't nominally competent. Why
is this so hard for you to accept?

But whether or not your amp's power output is a limiting factor is
substantially dependent on your speakers (and your room, and how loud you
listen). You cannot answer that question before you've chosen your speakers.

No. Choosing your speakers is the first step.

Now I'm sure you don't get it. "Nominally competent" means, in essence, flat
frequency response and enough power. An amp isn't competent unless it can deliver enough power.

Indeed they do, and lots of audiophiles believe them. Others don't, however,
and have offered some very good technical reasons why not.

This is often true when you know what the pricetag says. ;-)

I'd bet if you went back and compared those amps without knowing which was
which, you'd be a lot less definite.

It has nothing whatsoever to do with price, for starters.


One more time: A nominally competent amplifier is one that delivers a signal
into a particular load (your speakers, your room, etc.) without audible
distortion--that is, with flat frequency response and minimal clipping.

Now, go out there and buy the best speakers you can afford.

bob

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rbernst929

I'm simply pointing out that if there is a DIFFERENCE in the resulting
sound
when changing one element of a system, that ratifies the merchandising
of
different components. It does'nt matter if we can measure the
difference or
not within amplifiers, as long as the resultant sound is changed at the
listening position, then there is sound reason for a consumer to choose
among
different products. These differences create preferances which are
legitimate
buying decisions among products. Indeed, this is why so many different
amplifiers exist. Some people on this newsgroup think all amplifiers
are
perfect since 1950 and hardly any improvement has taken place,
suggesting that
all sound differences are in our minds, or resulting from sighted
marketing
practices. It does'nt matter. The only thing that matters is the
resultant
change in sound at the listening position when one element of a system
is
changed. If there is a difference, then the consumer has a valid
purchase
choice. If there is no difference, then spending $20,000 on a high end
amplifier as opposed to a $200 amplifier offers no rational reason.
-Bob
Bernstein.

You have asked from a place of affirmed confusion a series of questions
about amps. That one has questions is good, that questions can be posed
about a thesis doesn't harm the thesis, and that one might not accept the
answers does nothing to the correctness of the thesis. The amp that
doesn't exceed it's specs for a given speaker, with regard to current
reserves, headroom, distortion, etc. will most likely not be different
from another similar amp in a listening alone test as to being able to
discriminate which is which. The concept of threshold comes in here also,
various amp artifacts which rise above a certain amplitude,ie. threshold,
can be percieved and those which do not can not; as established in tests
to determine such things. Various types of signal distortion are
examples. The concept often bantered about of "mid high" are meaningless
when the above conditions are met. A "mid" amp that doesn't exceed design
parameters nor produce artifacts above known thresholds can not by
listening tests alone be distingushed from those "high" amps often found
on "reccomended" lists. Amp performance is today a commodity available
from any number of brands which satisify the above. You mention nad,
others have mentioned adcom etc. and all serve as well as those amps with
the famious "high end" marketing reputations and consumers of editoral
inches in the hi fi mags. Design folk have learned how to produce amps
which meet specs and threshold levels so as to make them to be percieved
the same using listening tests alone.