McIntosh C2300 noise


I’ve recently noticed that there is a buzz in the phono section of my c2300. I bought this used from a dealer and they are are helping me root cause the issue. I thought i’d share here in the mean time. The buzz usually goes up with volume. Not only does the buzz go up with volume - the meters show some gain as well. This happens with no source attached. I moved the C2300 to a different part of the home with no source or amp attached whatsoever - turning up the volume knob jumps the meters.  Is this normal?

https://www.youtube.com/watch?v=vH9hYnTN-iw&feature=youtu.be
pistha
pistha - If you bought your preamp from Audio Classics, you’re in good hands. They won’t let you down.
Sounds like a tube noise. Just as an experiment, gently tap the phono tubes while you hear the noise and see if that affects the frequency or pitch.
@kalali - that was the first thing i tried - while it makes the needle jump - it doesnt change the noise - frequency or pitch. Am gonna try borrowing some tubes just to rule out tubes