Please!, can anyone tell me if they have any experience with a quiet but annoying noise emitted by some Performers and Signature Voyager’s when you turn the Master Volume knob past 5 in either direction. I’m planning to buy an older Signature version, and this concerns me. 
This is a known problem and can be remedied. If you’re buying a signature edition, call Moog Music and ask if the four year warranty is transferable then they will fix the problem.