Most likely guess would be a burned screen-grid resistor or similar issue on one of the output tubes' sockets . . . an easy repair, but basic diagnostic and good soldering skills required.
more sound in left channel than right channel?
I have a tube integrated amp equipped with four kt88 tubes. for some reason im getting a lot more noise coming from the left side than the right. it throws off the whole balance of sound. Is this a sign of bad tubes or need bias? New to tube amps and at a loss. thank you-