First, thanks for everyone for their input.

Playing around with earthing etc is out of my league in terms of skill and understanding (plus George and Robert lost me a bit).

I have tried what Nutflush suggested and played around with cables etc. No luck. From doing this though it has become apparent that 4 things all need to simultaneously occur for there to be intereference through my speakers:

1. The power amp must be turned on (obvious I suppose, as I would otherwise hear nothing from my speakers hence no noise); and
2. The Oppo is turned on (includes standby mode); and
3. Cables are connected from the Oppo to another piece of kit (any one item, incl TV); and
4. That piece of kit, somehow, has a cabling system that can be traced thru to the power amp. It doesnt matter if that piece of kit is turned on/off or even plugged into a power source.

Point 4. is the important one to note. An example may help to clarify - its a little complicated.

I unplugged all other AV kit from a power source other than the power amp and headphone amp (both in the power board) and the Oppo (direct to wall). All 3 were turned on.

The only audio/video cabling from the Oppo that was plugged into anything else was the analogue outputs, which went into the headphone amp. 2 scenarios then followed.

Scenario 1: The headphone amp also had plugged into another one of its input, the analogue outputs from my Digital TV set top box (e.g. like a Sky HD / cable box).

Scenario 2: Only the Oppo was connected to the headphone amp.

Outcomes: Scenrio 1 = Noise; Scenario 2 = No noise.

I figured that the signal under scenario 1 was making its way back to the power amp via the various cabling. My set top box is also connected to the 568.2mm (via coax digital out), which in turn feeds the power amplifier. So, I figure that the "noise" was going from Oppo, to headphone amp, to Set Top Box, to Meridian, to power amp and finally speakers.

Under Scenario 2, the "noise" had nowhere else to go as nothing else was connected to the headphone amplifier other than my headphones.

* * * * * *

So, in summary, is it fair to say that the Oppo and my power amp just don't like each other? Given I had all other components unplugged, I am assuming it cannot be one of them rather than the power amp.

If it wasn't for Scenario 2 above -- and the fact that via headphones I have no noise -- my conclusion would 100% that the Oppo has issues (maybe it still does anyway? - it is the thing that started it all).

I hope the above is clear. I would appreciate comments on any flaws in my logic and if my noise-routing theory is just bollocks.

Kind regards




Last edited by markg; 2009-10-21 15:18.
568.2mm, M80