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V6 18 watt amp has been working fine for a year or so but last night after about an hour of playing dirty channel became very noise (crackle, pop, static). Noiced the 6v6 tubes were blue. Clean channel is fine. Changed tubes but still the same. I think I had a problem like this with my first Trinity amp and Steve advised to replace a bypass cap and it fixed the problem. Does this sound like the same thing? If so which cap will need to be replaced? Or is there any other suggestions?

Thanks

If you replaced it, it would be the 220 uf . I would also check the cathode resistor 250 ohm for the 6V6. I would have thought newtubes would solve that problem. Measure the cathode voltage too and check that its in range.

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Stephen
Web: www.trinityamps.com. Facebook: facebook.com/trinityamps. Twitter: @trinityamps

Thanks Steve....measuring 12v on pin 3 of EL84. But 21v on pin 8 of 6v6. I assume this is not good. Do I need to replace the 220 cap or the 250 resistor for the 6v6?

21V on the 6V6 is fine. We run the 6V6 in a Tweed at 22 at 400V. Your cathode voltages look OK.

Regarding blue glow in tubes, check this out: Blue Glow in Tubes

If the EL84 sound fine, it sounds like a component around the 6V6 so the 220 uf bypass cap could be the cuplrit. To test, use anything 25 uf & up with a voltage of 50 or more. Or you can temporarily remove it and listen again.

It can also be the solder joints so retouch them first.

_________________
Stephen
Web: www.trinityamps.com. Facebook: facebook.com/trinityamps. Twitter: @trinityamps

I still have been unable to fix the noise/popping/static problem on the TMB channel. Voltages are all good. Tubes have been swapped out a few times. I have not seen the 6V6 tubes with the blue shade for some time now. I assume the noise problem is due to a bad cap and I have replaced almost all the caps in TMB channel. Again the normal channel does not have the problem. Am I going in the right direction with replacing caps? There is only a couple left to replace but I do not have spares of them. Is there a way of testing the caps?