I have a quiet hum in the background - not audible at normal listening levels from my chair, but audible when you put your ear to the speakers. Becomes much more audible at loud volume.

Here's my buffalo box:



I've tried disconnecting the toslink power supply as that's crossing the signal output wiring, but that made no difference. Signal wiring from buffalo to ivy and from ivy to output rcas is shielded. Any pointers on what to try? Move the regs to another box?

ta

James

Thanks - grounding was something I was wondering about actually. As it's a plastic case there isn't a case ground as such. Should I put in a case ground and link that back to the earth point in the transformer box? Also, what would be the best strategy with the shielded cables? At the moment the connected end of each shield is at the pcb end. Where do I take the ground wires to case ground from? (hope that question is clear)

Btw, to the far right there's 2 coax inputs both wired to a dpst switch, which is then wired to a second dpst which feeds the dac. I've now wired the toslink board direct to D1 so the coax inputs and switches are deactivated for the moment.

Edit - as a wee experiment I've disconnected the shields from the output wiring and it's made no difference, so I'm assuming it's not that. I have another psu running off the transformer that's powering the ivy - I'm wondering if that's feeding some rubbish back in - might try disconnecting that at some point.

Edited by user Friday, October 24, 2008 1:20:07 AM(UTC)  | Reason: Not specified