Problem with new 20-amp dedicated circuits using PS Audio Power Port Premier receptacles

On Wednesday I had an electrician in whom I have great confidence install two new dedicated 20-amp circuits for use with Perreaux mono blocks when I move them to a new location in my exercise-area system. Both circuits originate from the main panel for the house.

To test them, I plugged in the amp that I am now using in the exercise area. In each of the new circuits this produced a fairly loud hum from the amp.

At the same time, I also had the electrician install another new dedicated 20-amp circuit for use with a treadmill in the exercise area. This circuit uses a normal 20-amp GFCI receptacle, and unlike the PS Audio receptacles, it does not have an isolated ground.

When I tested the amp by plugging it into this new GFCI circuit, there was no hum. The is also no hum in the dedicated GFCI circuit I have been using for years for this amp in the exercise area. This circuit is wired into the same panel as the new circuits.

This suggests to me that something about the isolated-ground receptacles – the PS Audio ones – causes this hum, and as a test, I am thinking about replacing one of the PS Audio receptacles with a standard 20-amp GFCI receptacle to see whether this eliminates the hum.

However, before I do this, I would appreciate any thoughts others might have about this problem. The two new circuits are unusable for audio equipment in their present state.

Are you hearing hum from the speakers or transformer hum that you hear from inside the amp itself? Which PS Audio receptacles are you using? Are there other devices attached to the amp that are concurrently plugged in on the old circuit?

EDIT: oops, OK, Power Port Premier.

The hum is coming from the amp itself. There is no sound coming from the speakers.

The old receptacle is in use. A surge protector is plugged into the old receptacle.

Plugged into the surge protector:

  • A Perreaux SM6P preamp,
  • a PWD MK II with bridge (connected to the preamp by AQ Sky xlr interconnects and the bridge is connected to a CAT-wired LAN);
  • a Cambridge Audio Azur 840C (which I use only as a CD transport connected to the PWD MKII through the toslink port), and
  • a Wadia iPod dock (which is connected to the DAC via the coax port) are plugged into the surge protector.
Is this a situation "ripe" for a ground loop?

Today, I isolated the problem.

Plugging the PWD MKII into any of three dedicated GFCI circuits – including the one with the surge protector I have used for years – while the amp is plugged into either of the two new dedicated circuits with PS Audio Power Port receptacles produces the hum.

I get no hum when the PWD is plugged into either of the two new dedicated circuits, even when the amp is plugged into the same circuit with the PWD.

Thank you, wglenn, it was, indeed, another piece of equipment that was plugged in “on the old circuit” that was causing the hum.

Now, I have decide to plug the PWD into one of the two receptacles along with one of my mono blocks, or to have the electrician return to install yet another dedicated circuit for the PWD.

Yay! The fact that the transformers are humming suggests that there is DC on the line but if it works this way then there should be no harm.

Monoblocks in your workout room… that should help put on the bulk!4_gif

wglenn, I only wish my work outs were to “put on the bulk.” They are partly simply to maintain aerobic fitness, but largely physical therapy to deal with disc problems in my lower back. I’ve done them pretty religiously for well over 20 years and have, so far, avoided surgery.

In any case, the electrician installed another dedicated circuit with another PS Audio Power Port receptacle, and I have no hum.

Great result!

Hehe… I know what you mean. Not getting any younger, that’s for sure.doh_gif