Arny Krueger <arnyk@[EMAIL PROTECTED]
> wrote:
> non-measurable parameters?
> About well-known switchmode power amplifier designer Bruno Putzeys:
> http://spectrum.ieee.org/feb08/5924
> "
> He went through four generations of circuit boards without listening to
any
> of them. Instead, he connected each board to an audio analyzer and then
> rejected it because the results weren't what he wanted. The fifth
iteration,
> though, looked good. Just before Christmas 2001, he brought a pair of
the
> amps home and connected them to the speakers in his living room. He put
on a
> CD of Spanish classical music and selected a song by the 18th-century
> composer Juan Franc?s de Iribarren, "Viendo que Jil, Hizo Raya." He
settled
> back in a chair and listened. It took him just a few seconds to reach a
> conclusion: "Straight in the bull's-eye."
> "
> The point is that Bruno Putzeys clearly believes that technical
measurements
> were sufficient to establish the sound quality of a high end power
> amplifier.
The longer version of the article is even more explicit
" At a visitor.s request, he re-creates the event [Putzys' first audition
of his UcD module],
with the very same CD and stereo components. The music begins to flow from
the speakers, and
Putzeys.s eyes seem to unfocus, like he.s lost in thought. There.s a
little grin on his face.
The sound really is remarkable.extremely transparent, neutral, and
precise. And yet there.s a
lovely warmth and force in the female vocals, and not the slightest trace
of harshness.
..It was a defining moment,. Putzeys says of that experience. "Until then,
I had subscribed to
a lot of audio folklore, namely that measurements don.t matter". He had
basically moved on
from his adolescent infatuation with vacuum-tube audio. .Tube designers
often build and see if
they like it,. he continues. .You never get to question what it is you
want to hear. In my
case, what I want to hear is music and nothing else..
In an engineer.s universe, Philips would have swiftly embraced Putzeys.s
UcD module,
incor****ating it into countless products. In the actual universe, the
module basically fell in
the cracks at the giant company. But in April 2003, an enterprising young
entrepreneur named
Jan-Peter van Amerongen visited Putzeys at Philips. Some years before, van
Amerongen had
started Hypex Electronics to supply amplifiers and other gear to makers of
active speakers and
to recording studios. He had heard great things about the UcD.
Ironically, the one thing he didn.t want to hear, at least initially, was
music amplified by
the module itself. .The only thing he wanted to see was the output signal
on an oscilloscope,.
Putzeys recalls. .He looked at it, and in about one minute he said, .Okay,
I want to buy a
license.. He had seen so many dreadful outputs, full of RF hash. He could
tell from the signal
whether it was well designed..
Not long after, Putzeys left Philips for Hypex, where he has pretty much
free rein to explore
the boundaries of class-D. Just .for fun,. he recently designed an audio
amplifier with 0.0003
percent total harmonic distortion, at full power, amplifying a
20-kilohertz signal. That
figure is more than 1000 times better than some very good solid-state
amps. In fact, it.s an
improvement that no human ear can detect, as Putzeys acknowledges.
But that figure is also about 30 000 times better than that of some tube
amps.a difference
that.s not beyond the ability of human ears to detect. Putzeys rejects the
idea, which most
tube-amp enthusiasts take for granted, that it.s okay.desirable, even.for
an amplifier to
..color. the music it is reproducing.
..Audio is not supposed to be art,. he insists. .Making music is art.
Getting it from the CD to
the listener should not be art.."
--
___
-S
"Hey pip squeak, who's L Ron, some new rapper?" -- Nic
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