At 09:00 PM 1/8/98 +0100, you wrote:
>The video input resistance on a tv is 75 ohm, but what is the AUDIO
>input resistance, and what is the maximum voltage amplitude ?
>

I believe the "nominal" audio input voltage is 300mv peak-peak.
Sometimes I see it specied as 1 volt.  As far as I know, there's
no offical standard, but typical op-amp levels always work fine
(use an op-amp that can drive 600 ohms).

This 300 mv should correspond to "0 DB". It should be the same level
as that used by "AUX" inputs on stereos.

I'd advise using a POT at the input to your driver stage so you can
tweak the output level, just to be safe.

You should be able to drive 600 ohms, but in reality the audio
input impedance of a TV or stereo is often 10K or higher.

The NE5534 is an excellent audio op-amp, but there are now
many other good ones for audio work.

Eric Engler