Help troubleshooting amp


Hi,
When I turned the system on this morning in anticipation of a long holdiay of music there was no signal in my right channel. I first checked all connections which were fine and then I subbed in a pair of replacement tubes for the right side of my preamp, still only on channel. I then switched my attention to my amp, I switched both pairs of 6550's from left to right. Now no signal in either channel! This leads me to beleive that the trouble rests with the amp. I'm going to try switching 6550's back again but one at a time to see if I at least get the left channel back. Regardless I'm pretty sure it's a tube issue but if anyone else has any ideas I'm listening. Why do these things only happen on weekends and holidays?
128x128jond

Showing 1 response by ecclectique

Hi Jond. Sounds to me like a bad tube[shorted] took out the cathode resistors in one channel and when you swapped them to the other channel, the same bad tube or tubes took out the cathode resistors in the other channel as well.If you have a tube tester, It would be a good idea to test all these tubes to ascertain what tube/tubes are shorted before putting them back in. Is your amplifier a self biasing circuit or can you bias each tube idividually?