The Amp Garage

Yes the MV pots are grounded to the bus wire. I traced the HT fuse back, and you are right it is similar to my 50watt except that it comes off one of the large (I think these are coupling) caps before routing through the fuse block and over to the CT of OT. I saw something almost (if not) identical ...

My (super crappy) meter says the pots are 860K.

Thanks Martin... I will measure the pots and get a value...had not done that yet. Of course that makes me wanna ask more questions... :) What function do the caps coming off the master vol pot serve? (is it to cut noise). And yes I thought to convert this to LarMar (one of a few I have studied) but ...

Hi Marshall Geeks (and I mean that in the most endearing way...really!), Since the noob (that's me) learned a LOT with my last question on my 50watt Mk2 JMP...and it sounds SO much better (I have had great luck with my 50watt since making a fix and re-bias plus changing preamp tubes) and plan to re-...

It's interesting to note, the wireless system Reeltarded refers to, must be popular enough to "bring it back":

http://www.solodallas.com/category/svds-replica/

...evidently the later Cetec versions were different (not as good).

All I can say right now is...WOW. There I'll say it again...WOWEEEEEE! I didn't get my chance to re-bias the amp until after the Friday night gig. Instead I used my 100watt and all night, was tweaking with mix just to get it dialed. We opened for Gary Small and the Coyote Brothers on Sunday, so Satu...

Thanks Leo for clarifying...the shunt method I was asking about, I have read about and watched on youtube. You are talking about the same method I went back and looked and they shunt from pin 1 (in these old Marshalls pins 1 and 8 are already jumpered). While I have no plans (ever) to get rid of thi...

Thanks xtian, that's exactly why I was interested in trying this method (keeping in mind the voltages I am reading are low, but with respect to ground, can be "heart stopping" of course). And I don't mean beautiful!

i am convinced that after heating the amp up for three sets of music, that cold solder joint just started letting the OT center tap (cold) solder joint flop around. That of course is now fixed. I just wanted to see if this method was correct BEFORE making an upward adjustment on the bias. I plan to ...

I am a total noob...so please forgive my stupidity in advance. (see my introduction). I "am" however a pretty quick study, so want to ask all the tech guru's for input here 'cause moneys tight and I know I can suss this out with some help. Last gig we did, my JMP MkII 50 watt dropped in volume (a th...

Hello all! I've been lurking this forum for about 6 months now because I want to learn "just enough to be dangerous" about my tube amps. I've been playing the same three Marshall heads (plus experimenting with many others) for about 35 years on guitar, and do almost all of the work on my guitars, so...