0
\$\begingroup\$

So I started working with troubleshooting a channel imbalance on the schematic attached, 12ax7 + 6L6GC push pull. But the problem seems to be a bit different...

My voltages seem to be a bit hot!! (a lot hotter I think...) V2 is even higher than C16 450V rating :S

Please see attached. Any locations/components I need to check first? Thanks a lot.

power supply voltages

channels and feedback

full schematic

\$\endgroup\$
  • \$\begingroup\$ An unregulated PSU like that may well supply more voltage when unloaded, so it's possible your tubes are not drawing their intended current. Which could be cool heaters, duff tubes, bias too negative, broken resistors. Compare the two sides, if you're lucky only one is dodgy and you'll see big differences. \$\endgroup\$ – Neil_UK Apr 10 at 9:18
  • \$\begingroup\$ one side has a bit of a wobbly output. 1khz/300mV input test on 8Ohm dummy loads. this is where my investigation started. To be honest im not sure what to expect in terms of voltages. Some other "120W" amps seem to have similar voltages. But it seems over specs (for the caps) \$\endgroup\$ – OHTO Apr 10 at 9:43
0
\$\begingroup\$

After reviewing tube amplifiers with similar power supplies (identical probably) the voltages seem ok. There is a little variation between channels but I think its within normal operation.

From "Peavey-Triumph-Schematic.pdf"

enter image description here

\$\endgroup\$

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.