Re: OT question about sound cards/chip-sets and high-end music systems




On Oct 16, 2009, at 1:50 PM, Paul E Condon wrote:

Analog signals degrade on long cable runs, particularly
the high freq. part of the signal.

Not if it's low impedance balanced, it doesn't. Not at 100' anyway.

Impedance and balance are two different things. Impedance only becomes
an issue when the wave length of the signal on the cable becomes
comparable to the length of the cable run.

That's interesting -- I never heard that. Maybe I just never dealt with cables long enough. I'd like to learn more about it (off list would be more appropriate, I suspect).

Balance OTOH has only to do
with rejection of common mode environmental noise, e.g. hum pickup, not
with loss of signal amplitude.

Yup. But hums and pops and buzzes and stuff definitely count as degradation.

But this is theoretical knowledge. It precludes me from believing much
of the marketing pitch of consumer grade electronics. I'm hoping to
find some practical information that is in better conformance the
established theory.

To an old audio engineer, that's gratifying to hear: today's hifi marketing is astounding BS. And if you want some really practical info about bandwidth and noise, get an oscillator and a meter and measure it.

I think you'll find that, coming from a modern solid state amp (vanishingly low output impedance), you'll be hard pressed to find significant high frequency loss on just about any 100' long piece of cable. Your definition of "significant" is allowed to differ from mine, however.

I'm older now than when I bought the hifi. Hearing declines with
age. But I can still tell the difference between the sound from my
computer and from my hifi.

I'd first suspect the DAC/ADCs and the analog circuitry in the computers -- in yours and the one that digitized in the first place. Or maybe the digital sound's sample rate. Or, of course, the file could be (badly done) mp3 or one of its buds...

It may be that the age of real hifi has
passed, just as the age of the vacuum tube has passed, but I'm hoping
not (for real hifi. I don't mind the new dominance of transistors.)

I was around at the transition. And the early solid state amps were, indeed, pretty nasty. Then somebody discovered how easy and cheap op- amps were :-(

But they've learned how to work with silicon, and things are much better now. These days, a properly designed solid state amplifier is at least as good as could be done with vacuum tubes -- and a lot quieter and more reliable.

Thanks for reading to the end of this rant.

You're welcome :-)

--
Glenn English
ghe@xxxxxxxxxxx




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