Tube Amp Archive

Think I got it! Thanks for the help! I found another preamp tube that was bad... And the power tube sockets where loose... Tightened them up ,cleaned everything again, and tapped the hell outta everything! So far so good! Thanks again! I know this is obvious to most, so I REALLY appreciate the input!

I'm having an issue with my 6l6 Bogner Shiva that you guys know WAY more about than myself! I'm sure it's something minor, but I'm not really sure where to start... So I'll give you the rundown... I had it on a gig and it started making a Loud staticky noise... Didn't matter if anything was plugged ...

Oh ok... Well The plate voltage was off period... No matter what tubes went where... One socket was lower regardless.

And maybe so on the preamp tubes... But I'll let it get hot and give it a try...

Sorry, xtian... Just saw your reply... I checked the bias with a weber bias probe... I have since done the bias mod and brought it WAY down! It was actually closer to 60mA per tube! Now it's down in the lower 30's... Though there is one other interesting thing of note... First off, I have a box of "...

Got the diode bridge and caps reinstalled, and touched up a few solder joints....
And...
We have lift off!!

Again, THANK YOU!


Maybe next I'll try to tackle the adjustable bias mod... This thing is pulling some juice! 470 plate volts and around 50mA per tube! Gotta get that tamed down!

Thank you, cassoulet that's what I was looking for! And that makes perfect sense! I was just worried about the changes done in the past... I'm going back over all the joints now to make sure there aren't any broken traces/eyelets... I'm sure it's gonna be something small now... And again, THANK YOU ...

Yeah, this started out as simply a burnt resistor and tube replacement...

Should putting those parts back in cause issues?


I don't mind throwing some parts at it... But at this point almost all that's left is the power transformer...

Well I'm not sure on pin voltages as I have the board out right now... Before I put it back, I was hoping for some opinions on the 2 caps missing in the circuit... Why would they be removed if they were? And the diode bridge ( db-1 on the schematic) where is it? I see br101 on the board between the ...

Here are some pics... Hope this will make it easier to visualize... [IMG:800:598]http://i67.photobucket.com/albums/h284/maddtapper/627d134569cd8e1e0a48f9961614bb7d_zpsehqjfaki.jpg[/img] [IMG:800:598]http://i67.photobucket.com/albums/h284/maddtapper/1434e5a46ad944856f94876fe19bc5cf_zpst4wp552q.jpg[/i...

Well... Still not working... Dammit! I was hoping to gain experience WITHOUT ripping my hair out! Lol! So to recap... No pun intended... Changed output transformer, Replaced all axial caps on power board Replaced tube sockets with ceramic sockets Replaced defective diodes,resistors.... Replaced and ...

D108 & D109 both test open both ways... So it turned into another day... Dammit... Well, hopefully after replacing those, I'll be in business! Hell, I've kinda rebuilt the whole thing, so it should be dependable from here out! Lol! Btw, thank you guys so much! This an amazing group and I'm glad I fi...

Ok, got everything cleaned up... Stuck in known good tubes... To reiterate: New caps (all axial caps) New ceramic tube sockets New power tranny from Hammond, lugs soldered in place. No more Carbon or arcing on the board... Now... About the 2 caps that where gone.... Any reason those would've been re...

Maybe a little... Lol! But I'm never gonna learn without trying! I'll do that. Never even occurred to me.

I just recently acquired a DOA Marshall JTM30 210 combo. I have done a few things so far and seem to have hit a wall... When I got it it powered on, with no sound. I took the chassis out and found a blown resistor... R126 on the linked schematic... I also changed the tube sockets and output transfor...