Thats kinda normal.

The AWE64, while an improvement over the SB16, still isn't that great with respect to rejecting external noise and having good output stages.

You may be able to improve things by plugging into another slot, or using a better PSU, or a different motherboard.

Also try muting or completely removing the CD Audio cable, and if that resolves the issue tr to find a better insulated one.

Thanks for replays.

Muting unnecessary inputs was my first step. I actually used 90-ies audio cards back in the days so I'm doing it automatically even on modern PCs where it's not necessary. 😀
Also I don't think it's normal noise. None of my other ISA audio cards YMF719s, ES1868f or even Creatives own CT2700 have it.

But changing PSU is actually good hint. I in fact have another full set of extra 440BX system components. So I can prove beyond any doubt if this is card issue.
Otherwise card itself is in good condition and is working perfectly.

A recap may also help, have you visually inspected the capacitors on the card? Especially the ones around the amplification circuit may have gone bad?