2. amps-preamps
  3. 1132847783

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
kgturner's avatar
kgturner
664 posts
 
jond:

it's usually blatantly obvious when a fuse blows if your using glass fuses. when they blow, the glass usually has some slight to excessive charring.
jond's avatar
jond OP
5,911 posts
 
Guys,
Member Scifi walked me through testing my fuse with a voltmeter and the fuse is fine. It looks like it's either tube related or worse. I should be able to get my hands on a replacement quad of tubes today and if those don't work it's time for repairs. Wish me luck!
jea48
4,522 posts
 
>>"I should be able to get my hands on a replacement quad of tubes today and if those don't work it's time for repairs. Wish me luck!"<<
Jond

Jond, imho if I were you I would take the amp to the repair shop first. Without knowing for sure what is wrong with the amp you might cause damage to the new 6550 tubes. The repair shop will test all the tubes including the two 9 pin small tubes.
http://cgim.audiogon.com/i/vs/i/f/1128880649.jpg
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jond's avatar
jond OP
5,911 posts
 
Jea48,
The repair shop is where the replacement tubes are. I'll do whatever they tell me with the amp, it's in their hands. Thanks for your advice and for posting a link to a pic of my amp, it's a sleek little beastie don't you think?
jea48
4,522 posts
 
Jond, if I understand you correctly you are going to take the amp and old tubes with you to the repair shop. They will be able to test the old tubes while you are there. Does the Amp have auto output tube bias adjustment for the power tubes, or do you set the bias mVDC voltage manually for the amp? If the bias mVDC voltage is way off you could damage any new tubes you would install in the the Amp. I still believe something is damaged in the Amp due to a shorted 6550 power tube...
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