Hi all,
I'm not an experienced amp builder, I've only built a few simple amps before, like a 5F1, a 5E3 and a single ended Supro clone. Now i'm afraid I'm in over my head.
I've built a AB763 clone from the Weber 6A20 kit, but there's no sound from the speaker.
I've checked the layout and wiring, and I can't find anything wrong. I've also read the voltages on the preamp, driver and power tubes, but I don't see anything wrong there either:
V1 (12ax7): pin 1 +159 v, pin 3 +1.3 v, pin 6 +162 v, pin 8 1.48 v
V2 (12ax7): pin 1 +157 v, pin 3 +1.3 v,pin 6 +163 v, pin 8 1.48 v
V6 (12at7): pin 1 +168 v, pin 3 +70 v, pin 6 +160 v
V7 (6v6): pin 1&5 -36 v, pin 3 +400 v, pin 4&6 +398 v, pin 8 20.3 v
V8 (6v6): pin 1&5 -36 v, pin 3 +400 v, pin 4&6 +398 v, pin 8 20.3 v
The only time I hear a sound from the speaker is when I measured the voltages on pin 3 on the output tubes, then there was a faint crakle to be heard when the probes on the DVM touches the pin.. The rest of the time it's comletely silent, there's not even any hum.
The Normal channel preamp section is working, I checked that by running a cable from the the coupling cap into another amp.
I would very much appreciate feedback on how to proceed with troubleshooting this amp!
Thanks!
I'm not an experienced amp builder, I've only built a few simple amps before, like a 5F1, a 5E3 and a single ended Supro clone. Now i'm afraid I'm in over my head.
I've built a AB763 clone from the Weber 6A20 kit, but there's no sound from the speaker.
I've checked the layout and wiring, and I can't find anything wrong. I've also read the voltages on the preamp, driver and power tubes, but I don't see anything wrong there either:
V1 (12ax7): pin 1 +159 v, pin 3 +1.3 v, pin 6 +162 v, pin 8 1.48 v
V2 (12ax7): pin 1 +157 v, pin 3 +1.3 v,pin 6 +163 v, pin 8 1.48 v
V6 (12at7): pin 1 +168 v, pin 3 +70 v, pin 6 +160 v
V7 (6v6): pin 1&5 -36 v, pin 3 +400 v, pin 4&6 +398 v, pin 8 20.3 v
V8 (6v6): pin 1&5 -36 v, pin 3 +400 v, pin 4&6 +398 v, pin 8 20.3 v
The only time I hear a sound from the speaker is when I measured the voltages on pin 3 on the output tubes, then there was a faint crakle to be heard when the probes on the DVM touches the pin.. The rest of the time it's comletely silent, there's not even any hum.
The Normal channel preamp section is working, I checked that by running a cable from the the coupling cap into another amp.
I would very much appreciate feedback on how to proceed with troubleshooting this amp!
Thanks!
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