Re: [linux-audio-dev] live pa questions

Andres Cabrera wrote:

>>Overheating of the amp is nonsense. Most amplifiers operate in class A
>>or AB anyway, and maybe in class D. Heat dissipation is independant of
>>the input signal for these amps. The types that might build up a problem
>>with heat (e.g. class H) aren't used in PA enviroments. And before the
>>amp overheats, your speakers will be dead.
>>
>>
>
>Thanks for clarifying. I remembered I heard about overheating somewhere
>with DC, and thought it was on the amp.
>Adding a small DC offset is one easy way of getting rid of denormal
>problems (in programs like csound and pd), do you know if this small DC
>offset is able to produce these effects?
>
>
I don't know about the output stage of a soundcard. (Almost) every
soundcard uses a delta-sigma DAC, which needs some sort of low pass
filtering. It needs an output buffer to transform the rather high
impedance of this filter to a low output impedance, so the question is
if there is some sort of DC decoupling impemented in this buffer. I
don't know, but using a voltmeter (or scope) while applying a DC signal
to the card will answer that.
if you take a look at the specs of the EMU1820M it states "Frequency
Response: 0.0/-.35dB, 20Hz - 20kHz" which would mean that it doesn't
output DC signals.

But as far as I know, most audio input stages are capacitively coupled,
thereby removing such DC offsets, so there is little chance that this
type of signals will propagate through the entire signal chain.

Greets,

Pieter
Received on Tue Apr 5 00:15:06 2005