No problems what so ever with any humms in my AA.

If it is a low frequency humm, it is most probably a ground loop somewhere.

Try to connect the AA plug the other way around in the wall outlet, just for reverse polarity, and see what happens.

Also coulsd be an interconnect cable...

BTW, tanx for your DTI quest.

I don't own an AA DAC, so I haven't experienced the hum, but I can say from experience with the Entech and a few other devices, the external power supply, if too close to other gear or cables, will cause a hum.

Maybe that's what it is, the complaints or discussions some people have mentioned with the AA units. Nothing more than the external power supply too close to other stuff, causing interference.

I wished I had put a bid in for that DTI for you- I haven't seen one go that low for a while, and like I said, I was convinced it was going to sell for a whole lot more. I'll keep looking.

Tanx Paul.
EMI's that comes from power supplies in close contact with "bad" IC's are not a good idea. That's why a IC with a good shield against EMI's and RFI's are always a good choice.
There are so many freq's in the air nowadays...

Making electromagnetic fields visible:
A piece of spooky-tech, an electronic device for detecting and giving form to the invisible world of electromagnetic fields. The explanation on the site is slightly torturous artspeak, but the concept is kind of interesting.

http://scrying.org/doku.php

Your travails reminded me that somewhere I have an AA headphone amp. I got it new and the gain was too low for the headphones I was using. I spoke w/ Dusty Vawter @ AA (IIRC @ Channel Island Audio now) and he suggested swapping in different value resistors. I did, much better but still not enough gain.

Soooo...... get out the iron for round 2 and I did the same thing to the traces. I should have gone with my gut and socketed those points the first time. Then I could have merrily swapped in any value without issue. I need to dig it out, repair the traces, socket them, and put the headphone amp back into use. After I screwed it up I didn't want to look at it anymore.