Noise problem in Jeff Rowland Consonance

[Pengvim]

Hi.

I've got a Jeff Rowland Consonance that's not behaving well.

I get a "ritch"-ing noise (with a bit of hiss and pops too) that comes and goes in intervals. Seems kind of random.

It goes away when I turn the volume to 0 or if I press Mute, but not if I use R Cut or L Cut, it stays in that channel still. I think it might only be in the right channel.

I'm using it with a Model 1 poweramp from the same company which is set to 600ohm input impedance and the output impedance of the preamp is 300ohms if I recall correctly.

Has anyone encountered a similar problem with this preamp before?

Appreciate any help I can get. I've also sent mail to Jeff Rowland.