Burson Audio low level noise

It sounds like a ground hum issue to me. I previously owned a Burson 160D that gave me a slight 60hz hum when hooked to my amp. I ended up having to ground the 160D to my amp using a lightweight piece of wire. Wrap the wire around a chassis screw on your amp and the Burson to see if that does the trick. Best of luck!

Gentlemen, the cause for the hum is in the unit itself.
I will not publish it here due to legal restrictions, but it
can be changed by a repairman. Please send me an
email if you want a hum-free preamp.

sold it back to Burson and they gave me credit towards a Conductor. Its a way better unit.