GCPH Buzz / Hum

I am using the GCPH with a Pro-Ject Classic turntable with an Ortofon 2M Blue cartridge, and a Bryston 4BSST power amplifier. I am receiving a large amount of hum / buzz that becomes easily audible at low-medium listening levels. If I turn above the 2 o’clock position, it is very loud. I have tried the following all to no avail

  1. Use a “cheater” adapter for the GCPH to lift the groud
  2. Try both the balanced, and single ended outputs
  3. Vary gain settings
  4. Try different cables for both inputs, and ground
  5. Unplug the inputs, and ground from the turntable

Does the unit hum when the turntable is not connected to the GCPH?

Hi Paul,

Yes, it does hum / buzz louder with the turntable connected however. Interestingly, the turntable does not hum with my other phono stage.