new jtm45 style build.....

[rockgod212]

yep.........I had a bad mains cap, just stuck a spare 40u@450v in it and the issue went away. I went ahead and ordered 3- 30u@500v supply caps, 47nf@1000v for the recto/ standby pop issue, I also got some different voltage dropper's so i can play with the preamp voltages. I should be good here on out. the amp sounds a lot better since i changed that cap. it sounds pretty good with my g12 80 cab too. i should have known better than to use cheap caps, but oh well live and learn i guess.

[rockgod212]

well, it worked for about 5 seconds then it start motorboating again. im stumped on this. I tried lifting the nfb wire, still does it, tried changing pre amp tubes and recto tube still does it. what can it be, I don't believe I have the primaries reversed as I matched the classic tone leads to the metro leads, so im sure I have it wire right, unless that doesn't even matter.

help needed.

[rockgod212]

well it wasn't any of that, low and behold it was a cold solder joint at PI circuitry, I got it working, but I still have to reflow a few spots to make sure it holds, so far so good. man this amp sounds killer with a les paul, some drive pedals through some g12- 80's. it rocks.

[rockgod212]

well after some reflowing of solder joints, I still had the occasional motorboat issue or leaking coupling cap issue. I could tap on the joints and or tube and I was getting microphonic static noise, so I changed out v2 and v3 with the shungy 12ax7's and the issue is gone. i knew i had some bad jj ecc83's in my bag, but ive never had this issue before with a v2 v3 tube, strange in deed, so now I know something new. these shungy pre tubes actually sound pretty good in this amp, so I think I will keep them in for awhile. I suspect these high pre amp voltage's on v2 and v3 fried a few tubes, so I will be lowing the voltage's a bit.

I also like a .22 over v2's 820r and I like the 47k@8ohm tap, so time to wire that in correctly.

[rockgod212]

the issue ended up being some microphonic tubes in v2 and v3, never had that before. well this amp is done for now at least. I changed out the cheap supply caps for some F/T 30uf's and OMG does this amp sing with tone now. I did prefer the NFB at 47k@8ohm tap and a .22 over v2' 820r. it just rocks with a ZW overdrive and clean boost's. all guitars rock through this amp. using it with some old VOX/ USA bulldog speakers.

[rockgod212]

heres a pic. this amp rocks.

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