Changing Duet power supply cable

[chemguy]

I am considering switching to a linear power supply for my Duet as I am having some ground loop problems in my system. I will also need to pick up a dc power supply cable and was wondering what the exact size of the barrel plug connector is that attaches to the Duet.

[Phil Leigh]

I am considering switching to a linear power supply for my Duet as I am having some ground loop problems in my system. I will also need to pick up a dc power supply cable and was wondering what the exact size of the barrel plug connector is that attaches to the Duet.

The stock supply has no ground connection and so cannot create ground loops (ie two seperate paths to ground, with a resistance between them that causes current to flow).
Can you explain a bit more about your setup? A linear replacement may not fix your issue.

[chemguy]

Hello Phil:

I had read this in another thread (from iPhone): "Two reasons to replace the OEM Squeezebox PS: original PS has died, one has a ground loop noise that replacing the PS solves the issue."

Here's my situation:

I have the Squeezebox Duet (running it wirelessly) and use the digital out on the Squeezebox receiver to a DAC in my integrated amp (Bryston B100 SST) for listening in our living room. I also use the analogue out to a separate small 2-channel audio receiver (Cambridge Audio Sonata) which powers outdoor speakers.

When both outputs on the Squeezebox receiver are connected and I am listening to music in our living room (through the digital out to the Bryston), I get brief signal losses very time someone turns on lights in the house, powers up the dishwasher, turns on a guitar amp etc. (Note that the power to the Cambridge receiver is off while this is happening). It's just a brief hiccup, but it's there. All my audio electronics are on a completely separate circuit in the house and on a power conditioning surge protector. The router (computer) is in the adjacent room. Signal strength is good. Recently I noted that when I unplugged the analogue out from the squeezebox receiver, there were no more signal losses when other appliances and lights in the house were turned on. It seems that JUST using the digital out ALONE has solved the problem.

Could this be a ground loop problem? Could this have something to do with the fact I have the SBR's outputs going to two separate amps?
1. When I listen to the outdoor speakers (analogue out on the squeezebox receiver to the Cambridge amp), there are never any losses with appliance use. If the Bryston is on and I am listening to the same feed in our living room at the same time, losses are evident through the Bryston.
2. When I run both the analogue out and digital out to the Bryston amp, there are no losses. I have switched back and forth between analogue and digital on this amp and playback is smooth as appliances are turned on and off.
3. I am using quality interconnects. I have switched these around and concluded this is not the problem.

The bottom line is this: it only happens when listening to the SBR digital out through the Bryston while the analogue out is plugged into the Cambridge (and it makes no difference whether the Cambridge receiver is on or off).

[Phil Leigh]

Ah. Are the Bryston and the Cambridge connected to the same Power strip/mains socket?

You definitely could get a ground loop/noise problem this way, if there is ANY resistance between the ground plane of the two amps. However, the SB PSU is not part of this problem, as it has no earth connection to the SB outputs.
This is why I was asking.

How long are the analogue cables between receiver and Cambridge?


Do you have a multimeter?

[chemguy]

Hi Phil:

"Ah. Are the Bryston and the Cambridge connected to the same Power strip/mains socket?"
YES

"How long are the analogue cables between receiver and Cambridge?"
1 m

"Do you have a multimeter?"
YES