JMPGuitars wrote: ↑
Tue 05/05/20 12:51 pm
Bieworm wrote: ↑
Tue 05/05/20 12:17 pm
Found the problem...
It were the wires from jack to point x and y for the fx loop. That mod is giving me nothing but trouble ... I removed them...
Amp is shining like a star now. Dead quiet!!! Noisewise that is...
BUT found another issue.. the trem comes on very slow. It takes a few seconds before it starts...
Did you properly ground the jacks? I generally ground mine on the same ground line as the speaker outs. Probably more out of convenience than anything else.
Here's a recent build of mine with the FX loop:
You can hear how clean that amp is here: https://youtu.be/tY9RUIO3KjY
and here: https://youtu.be/3oSZVg2STXw
Remember that lead dress is always important. If you have a wire running the wrong way, it will get angry. If something's not grounded correctly, it will be even angrier.
Try swapping to a different tube for the trem. If that doesn't solve it, do the highlighter test for the trem section.
Aha! I didn't ground the jacks. There was no grounding on the layout of the EF86 extra... damn... that's probably it!
Here's the new voltage chart. PI even more off on the plates. What can I do with that?
As for the trem tube.. I tried 5 different tubes from different brands ...even a 12ax7h. The idd thing is that it was the same tube I had in there before the change-over from 18w classis to modern classic.
Anywayz...the trem oscillation is notorious in regard to the ideal voltages. Will look into that thrash online.. there are plenty of threads that treat this issue...
I had to do the snubber cap on the plates of the PI (150pf) to get rid of too much brightness that gave a lot of fizz. Doing the PR mod afterwards when I get the zeners...
Amp sounds awesome by the way!!!!
Tomorrow I'm gonna raise the B+ on the PT. Wire it for 230V instead of the 240V now.
My tremolo TMB is wired like that too. I like the extra volume ...it's a pretty significant difference. That will probably lift some voltages and maybe kickstart that tremolo sooner. It's worth a try... it's an easy reversible mod...
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