Trevor Wilson wrote:
snip
**A "nutter"? Ok, smartarse: YOU provide some hard facts on why YOU think
that the addition of autoformers to an already decent amplifier can
possibly
improve the amp's performance. I'll wait.
**I'm still waiting Bret. How about providing some facts?
The only fact that is directly relevant is that those who choose Mac
amps with autorformers either prefer them or are so dumb they don't
know the difference.
This is well documented.
**Nope. What is documented is this: Bret Ludwig has a preference for
autoformer equipped amps, but cannot say why. Bret Ludwig has NEVER
performed a blind test between two, otherwise identical amps. One
autoformer
equipped and one not. IOW: He has no science, no facts and no logic.
**I guess I should have phrased this as a question. Bret, have you ever
performed such a comparison?
Only an unscientific one betwen the 7200 and 7270. They sounded
exactly the same to me, which is what I had expected to find.
Disadvantages are cost and weight, and the ability of non-transformer
coupled amps to meet even better THD specs. All solid state Mc amps
except the very first models have THD specs well into the
don't-give-a-**** catregory.
**You've neglected the other disadvantages: That of output impedance and
the
ability of the ap to act as a pure Voltage source.
**No comment, Bret?
I already did.
Many good solid state amplifiers had transformers including the
legendary Altecs.
**Sure. That was when silicon was expensive and iron and copper was
cheap.
Now, the situation is reversed.
McIntosh prices are set by what the market considers high enough to
earn the buyers' respect, not by build cost. They are building UP to a
HIGH price.
**You don't know that. You're making assumptions. A big part of the reason
why autoformer equipped McIntosh amps are more expensive than others, is due
all the copper and iron.
You may feel they are overpriced. I personally do feel they are very
overpriced. I don't buy them. I suspect you do not either. Those who do
like them and believe their performance is adequate.
**You don't know that. Some people buy them due to the deluded nonsense
you've written. Some buy them, because they have that old fashioned look
about them. Some buy them, because they THINK they're better. I know. I've
serviced them for clients and most say pretty mcuh the same thing: "I bought
it because it has a good reputation." In fact, one guy brought his Mac in
for service. I replaced all the carbon composition resistors with metal film
types, the transistors with late generation types and all the caps with
modern types. He was stunned at the improvement. The thing which surprised
me was that, for what was a premium product in it's day, that it used carbon
composition resistors, when 'cracked carbon' types had been available for
many years prior. Penny-pinching by McIntosh I guess.
I guarantee no one has ever bought a Mc amp due to my writings.
If Mc went the Trevor route and put in a bigger power transformer,
more heat sinks, more outpput devices to make up for the lowered build
cost of the autoformer they would no longer have a better amplifier of
the existing power rating, but another amplifier of a higher power
rating.
**WRONG! They would have an amp of the same power rating, but with far
superior load tolerance.
The autoformer approach gives the SAME power across the likely
load impedances.
**And THAT is exactly what is wrong with any transformer coupled amplifier.
Save one or two rare speakers, ALL speakers present a varying load
impedance. Here's a rather extreme example:
www.rageaudio.com.au/kappa9.jpg
This speaker, like 99.99% of all speakers 'expects' to be driven by a 'pure
Voltage source'. IOW: As the impedance falls, the Voltage remains constant.
As a consequence, the power output will increase. This is normal. What is
not normal, is to deliberately cripple an otherwise good amplifier, by
causing it to deliver less Voltage, as the load impedance falls.
A McIntosh autoformer equipped amp will drive the above speaker very
well, although it is not a terribly well designed speaker to be sure.
The autoformer is a small cost in the building of the amp, we may
safely predict,
**Yeah? Seen the price of copper recently? How about the cost of an
autoformer? How about the extra freight costs asssociated with an amplifier
which is heavier than it needs to be?
as McIntosh has never been about high build cost but
about the lowest build cost consistent with what they consider good
practice.
**Most manufacturers follow this practice. Where McIntosh diverges, is that
they fit autoformers to their amps, solely to differentiate their amps for
all the others on the market. It has nothing to do with performance (which
is worse) and everything to do with offering consumers something different.
So if you don't want an autoformer equipped amp you have many other
choices and should not worry about McIntosh then.
They wind their own transformers and at a cost competitive
with vendors like Endicott Transformer and Schumacher, probably because
Upstate New York has a lot of cheap skilled labor available.
**Really? How much are their autoformers?
Bought as replacement parts, very expensive. The build cost is what is
relevant. The autoformers used in the 300 watt model "cost in the
ballpark of" $100 each to make including the C-cores, can, wire, and
direct and indirect labor, as of three or four years ago, from a source
I won't identify by name but will say was, and is, in a position to
know.
I don't want a power amplifier with "zero" output impedance,
regardless of theory, and Mc owners don't either.
**You don't know that.
I know what I prefer as fact. I infer what others prefer from their
buying patterns. Drag racers don't like Weber carburetors, and camera
collectors don't like Polaroid cameras. I can state these things with
reasonable certainty by knowing enough of the markets for those things
over long enough to say I am in general correct. You can say that
because I don't know each and every drag racer or camera collector in
the world I can't make those kind of statements, but we both know you
would be ful of ****, as with the present discussion.
**Predictions are like arseholes. Everyone has one. I predict that McIntosh
will dispense with autoformers within 10 years. If they remain in business
for that long.
Mac HAS made autoformerless models and may be doing so as I write
this. But the Mc customer appears to prefer the autoformer coupled
ones.