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Hi Guys,
I’ve had a lot of fun building this kit! After testing all of the TPs I plugged in a guitar and was rewarded with the sweet sound of a tube amp into a 1×12 cab!
One thing that concerns me is that while all other readings were close, the reading at TP6 which should be 86Vdc, it read 157 Vdc. Input voltage was 122 Vac.
Should I be concerned with this?Thanks for your help.
Regards,
Alex
I’m glad it’s working, but it is very concerning that the voltage at TP6 is nearly twice what it should be. My first thought is to ask if you are sure you are measuring it correctly. If so, is R3 and R4 the correct values? What voltage do you get at TP10?
-BrachHi Brach, thanks for responding.
So after the initial testing, I set the amp aside and went on to complete the cabinet. It’s been 10 days. I plugged everything in…
nothing! No sound. No static. Nothing.
Today, I disassembled it and started testing voltages again. As before, I get about 122 V ac coming in. TP 1, which measured 175V before is now reading 193V. TP2 which originally measured 7.08v is now 7.43V. At TP4 which originally measured 163V is now 0v at both ends.
How should I proceed to troubleshoot?
I’m pretty handy with a soldering iron but I have only basic understanding of electronics.Thanks again.
Alex
Hi Brach, thanks for responding.
So after the initial testing, I set the amp aside and went on to complete the cabinet. It’s been 10 days. I plugged everything in…
nothing! No sound. No static. Nothing.
Today, I disassembled it and started testing voltages again. As before, I get about 122 V ac coming in. TP 1, which measured 175V before is now reading 193V. TP2 which originally measured 7.08v is now 7.43V. At TP4 which originally measured 163V is now 0v at both ends.
How should I proceed to troubleshoot?
I’m pretty handy with a soldering iron but I have only basic understanding of electronics.Thanks again.
Alex
It seems like you may have widened the tube sockets too much…try tightening them by prying the 2 pieces of metal in each socket closed. Pay close attention to pin 10 (near TP4 that is measuring 0V).
See if anything changes after you do that. If not, let me know what the other TPs are measuring. Don’t leave the amp on too long when you measure these things, because it might not be too good for the tube to be exposed to these wrong voltages. Also, make sure you have an 8 ohm load plugged in to the amp while it’s on.
-Brach
