Originally Posted by markg
Thanks again everyone for their suggestions. Some more work tonight/tomorrow night its seems

Originally Posted by NutFlush
[quote=markg]

Mark,

a few follow up questions:
- did you have an active sub (or any other active speaker = power plug!) connected to your amp? If so: what happens if you disconnect it?
- what was the effect when BOTH amp & Oppo were connected to the SAME power board (including twisting one of the 2 power plugs as a second scenario)?
- do you have a power cord WITHOUT ground (meaning only 2 pins but no other metal parts that connect to any part of the socket)? If so: what is the effect if you try it on the OPPO (or amp)?


The sub was not plugged in - in fact, I have not had it plugged in since I got the Oppo.

It is worse when both Oppo and Amp are in the same power board and it is worse when there are just the 2 of them alone (i.e. more components = reduced noise level). I have not tried twisting.

I dont think I have a cord with 2 pins that would fit the 3-pin IEC socket on the amp and Oppo.

I will try an optical connection on the Set Top Box to see if that helps. I have a spare cable. I will also try unplugging the antennae - I did do this last night but don't recall the exact time when I did, but it didn't help.

Mark,

just to make sure we all understand what's going on:
- When you connected just the Oppo to the amp were there any other cables connected to either the amp or the Oppo? It is vital to disconnect all cables from the two components. If you leave any connection say from the amp to your set top box you may have a ground loop going through the set top box (in through the cable from the amp and out into the antenna or through the power plug even when switched off, because the ground is NOT cut off even then).
- Also make sure the subwoofer is disconnected (not just turned off).
- This should leave you with: 2 power cables, 1 audio cable from Oppo to amp, several speaker cables. Nothing else!
- Are you using 2 power cables that both have a ground? Does the amp have a ground receptable for the power cord?
- Does your amp allow a "ground lift" (physical switch or maybe in the setup)? What model is it anyway?
- Try placing the Oppo as far away from the amp as possible. Maybe the amp induces a current in the Oppo.

Since you write that plugging more components into the amp reduces the noise I would strongly guess that there is NO induced current but a ground loop. Plugging in more components offers the current different paths and if those paths are easier (= less resistance) then the current will take this route. That's why connecting the 2 chassis (attach to any screw) with a thick cable should help (current flows through the thick cable that has less resistance thereby reducing the current in the audio connection).

Tell us how you go, cable guy smile