Low Noise Sound card
"Arny Krueger" wrote in message
...
Both the sound card and the amplifier are properly
modeled as a fixed noise source and a variable signal.
Therefore, as you turn the signal down, the SNR of both
the sound card and the amplifier will get worse because
there is less signal but the same amount of noise.
Do tell how a passive analog attenuator will reduce the
signal but leave the noise untouched?
Quite easily if the most significant noise source is downstream of the
attenuator, which is often the case.
Arny I'm really surprised I have to spell it out for you, a passive analog
attenuator reduces both signal AND noise at *it's output* (amplifier input)
The OP *wasn't* complaining about his amplifiers noise!
IF that was his problem, asking for a low noise sound card is even more
stupid!
This is one of my favorite "audiophile myths". The audiophile has a
power
amplifier with 80 dB SNR, attached to a CD player (93 dB SNR @ FS) with a
digital attenuator. He's beside himself with anxiety over the issue we are
discussing. He *solves* his alleged problem by introducing a passive
attenuator. In fact, the best case is that he did not further muck things
up.
****, it's a pretty woeful amplifier that only gets 80dB S/N these days!
Hardly "audiophile" quality!!!!
Of course you can't *improve* on the amplifiers s/n, but
a digital attenuator does have a fixed noise floor
greater than a passive analog one, which is only governed
by it's thermal noise floor.
Yes, but the amplifier's noise floor is often the weakest link,
particularly
if the amp is tubed.
For a tube amp perhaps, but power amps with over 100dB S/N are easily
obtained these days.
My rule of thumb for a good SS power amp is around 100 dB,
which is about the same as a good CD player.
Exactly! (well actually no CD player can really do 100dB wide band since
it's above the theoretical maximum for 16bits, but let's ignore the slight
difference)
However it can easily be degraded by running the amp gain flat out and using
the soundcard digital attenuator as the OP said he was doing!
MrT.
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