Strange ground loop...?

Hmm, no phono in... just a pair of RCA's. It's a Yamaha M-40 power amp.
03-07-09: Djembeplay

LOL, sorry about that.... I must have had a brain fart, LOL.
For some reason I was thinking preamp in regards to the ground screw...
DAC > to > preamp.....

At any rate I would not connect the chassis of the amp to earth ground.

As for the non polarized plug it might be worth your time to check for the proper AC polarity orientation for the power transformer of the Amp. http://www.boundforsound.com/tweak.htm
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Glad to hear you found the source of the buzz.
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"If the cable is coax, the shield connected at both ends of the cable."

Bob - I was talking about interconnects.

Ok... I have to revive this thread. I just received my new replacement cable as well as a new passive pre-amp. I hooked everything up and **suprise!** the whining interference noise is back in full force!

So, I started to switch around the orientation of my interconnects. I have one from my DAC to my pre and the other from my pre to my amp. Pretty standard.

Now, I have found a configuration that works pretty well, but not perfect... there is still a very faint 'whining' noise when my volume on my pre-amp is set between 8 and 11 o'clock. Beyond that, it's dead silent.

Now, tell me how this makes any sense... at all:

Let's say interconnect 1 has terminals A and B. Interconnect 2 has terminals C and D.

Here here my results, running sequentially from DAC to pre-in to pre-out to amp:

A-B-C-D : loud whine
A-B-D-C : loud whine
B-A-C-D : loud whine
B-A-D-C : loud whine
C-D-A-B : loud whine
C-D-B-A : loud whine
D-C-A-B : loud whine
D-C-B-A : dead silent except for faint whine at low volume

I don't get it... at all. What gives? If it's a shielding problem, then shouldn't configuration A-B-C-D also work just as well?

What should I do?

Ok... definitely frustrated now.

Even with configuration "D-C-B-A" when at volumes other than 'full' on my pre-amp, I get this really fuzzy, static interference when lower frequencies are strong (deep base).

This is the second passive pre-amp that has done this and it is a different make than the first... sooooo, I think it's safe to rule that out at the culprit...

It's these cables I bet... They are BlueJeans cables, though... I thought these were supposed to be pretty good???

"I don't get it... at all. What gives? If it's a shielding problem, then shouldn't configuration A-B-C-D also work just as well?"

Shield should be grounded on the receiving end (in my opinion) so your configuration D-C-B-A suggests that terminals C and A have shield grounded.