Relocating power transformer in PS Audio GCPH


I just recently completed a project to relocate (or actually disable) the torodial power transformer in my PS Audio GCPH phono pre-amp.

I built a separate outboard power supply with a similar torodial transformer (so I could leave the stock one installed but disconnected) that has 132,000 mfd of capacitance. I run the V+ , V- and Gnd busses up to the GCPH and feed them through the chassis using an Amphenol connector, and run wiring from the connector to a molex style three pin that matches the connector on the original GCPH transformer. I removed the IEC AC connector (and associated circuit board) and mounted the Amphenol connector to a blind off plate that mounts in place of the IEC.

After the modification, the hum (60/120/240 Hz) noise component is completely gone. Much quieter on the 60 dB and 66 dB gain settings. I can also use more of the volume control than before.

This setup allows me to go back to stock if desired, as I did not disturb the position of the PS Audio power transformer (which is critical). But I doubt if I will go back beacuse the new noise performance is so much better.
dhl93449

Showing 3 responses by swanny76109

Dhl, This is a really intriguing mod. We talked about our experiences with the GCPH on the earlier thread a couple weeks back. My own stock unit is sounding really good right now after getting the rest of my front end dialed in just right. I'd like to learn more and ask a few questions. Can you pm me at jswanson at hotmail dot com?

Thanks! Swanny