I purchased a used R8 without driver tubes. Tonight I installed a new quad of KT88's. Volume turned all the way down and powered it up. After about 5 seconds I got a very loud squeal from the right channel. I turned the power off and the squeal faded away. I disconnected all the inputs and tried again. Same story left channel is silent and right channel produces a scary loud squeal. Speakers are Klipschorn's. Any ideas? Swap V1 V2 and V3 V4? I have an old set of EL34'S I could try. I don't suspect input tubes since volume is all the way down. 30 day warranty just send it back maybe...