I'm still debugging what I think is parasitic oscillation causing weird fizzy swirly distortion in my Ceriatone Plexi clone (without much luck). I need to have the board in the chassis exposed while working on it so I can do things like take voltages, listen to the audio at various points, and use an oscilloscope to probe the signal. I can rest it upside down so that it's balanced on the transformers and EL34s, but the EL34s get so hot that I'm not it's safe to rest it on most surfaces - things could burn or melt. How do people manage this? Is there anything safe I can rest the amp on upside down?