Squeaking/Paper Crinkling Noise Coming from Lamm LL2.1

It really sounds like a noisy tube to me. 

Have you tried rebiasing amps?

Thought it was a noisy tube too. Replaced all the tubes and the sound was exactly the same, so that's not the problem.

The amps are solid state but the sound goes away when the Lamm is muted or off so it's not related to the amps.

Thought it was a noisy tube too. Replaced all the tubes and the sound was exactly the same, so that's not the problem.

Tubes from Lamm? Some preamps are very sensitive to noisy tubes, even good quality brand new tubes. Sometimes you need to select only the finest low noise tubes and even then you can get one that doesn't work. The sound you describe sounds just like what happen in my CJ preamp. I'm out of ideas unless you have some other tubes upstream?. 

Very low noise tubes from Brent Jessee. Also, there's no way if I replaced all the tubes even with less low noise tubes, the exact same sound would be coming out. Something would change.

No other tubes. Just Herron M1A monos. 

Can it be some other electronic component like a capacitor?