amp with very low ground noise

[kenny12]

atm i'm just using the amp since i just got it.

the soundcard is an m-audio audiophile,

headphone amp set at 10 gain with very low noise floor when using a audio technica a700 headphone

i plan on using an stepped attenuator as the pre for the amp.

edit: also the noise is def from the amp itself, i've tried with no input with similar noise.

basically i just wanted to know if it was worthwhile ripping out all the eq stuff or is the tda chip generally noisy

[sangram]

The TDA7293/4 are not noisy chips at all.

Nor is the Audiophile, for that matter. I have a Delta66, essentially the same thing, but dead silent into an amp with a 26dB (x20) gain.

I wonder whether the way you have it connected is an issue. Do you have the original 2496 or the USB version? I assume if you have a headphone output it's the USB, then, well, m-Audio floats the cold end of the balanced connection off the chassis ground, it's not a 'real' balanced output.

If you hooked it up with the shield disconnected to an unbalanced input (very likely), you will have a noise fest all the time.

I went crazy trying to troubleshoot this very same issue on my Delta, till I ripped the dock open and found the 'balanced' output was not really so, and I would have to short pin 1 and 3 at the amplifier end, and lose the noise rejection benefit of a real balanced connection, or wire it up without the cold end connected at all, which is what I ended up doing and it's quiet as a kitten right now.