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  1. I

    Grid stopper question

    I just saw what you mean by the resistors looking like the were connected to ground. It does look like that. The bare wire you see is actually just holding those other wires in place a little better. It definitely looks like theres another connection from it though if the bare wire is what you...
  2. I

    Grid stopper question

    I know the grounding on this particular amp isnt stock. The pots arent bussed together etc..but this would cause a ground loop with the way those input resistors are connected to the jack? I'm a little confused, I should put the 68k resistor on the tube socket? Or do you mean 10k resistor? I...
  3. I

    Grid stopper question

    So right now I've got more like 16k then since I'm using two 33k in parallel? So you're suggesting either use a single 33k or the standard two 68k in parallel which is basically 33k anyway? As well as remove the three 10k grid stoppers...will do! Also I will take care of that brown wire...
  4. I

    Grid stopper question

    Hi, just to preface I'm not talking about on pin5 on power tubes. I attached a picture below and i'm wondering if this in theory should be identical to having the regular 68k input mix resistors? This amp use to squeal quite a bit turned up. so the 68k input mixers are disconnected on the board...
  5. I

    Question about jtm45

    Thank you!! Gonna spend tonight doing just that
  6. I

    Question about jtm45

    Man, you folks are great. Thanks. Yeah I've been slowly learning but I'm not the quickest with picking stuff up sometime.
  7. I

    Question about jtm45

    This is where I'm a little lost. If that particular 10k resistor is for the v1 and v2 preamp tubes then what does the PI have to do with it? Is it that v1 and v2 ultimately send the voltage on to the PI tube? But then that doesnt make sense i guess if the PI voltage is dictated by the PT? So...
  8. I

    Question about jtm45

    When you talk about the two 10k in series on the el34 amps are you talking about the resistors by the bias caps? I only ask because I want to be sure we are talking about the same thing because I dont think I've ever seen 2 10k resistors in series on any Marshall's by the preamp filter cap. I've...
  9. I

    Question about jtm45

    Dang, that sure is pretty. I wonder why he used those ceramic caps all face down instead of showing the value lol. They look like some NOS CRL or mallory ceramics I have. That cab sounds like a dream!
  10. I

    Question about jtm45

    Sorry, I may have that wrong. I've just always heard them called decoupling resistors. Or maybe that's just for the 1 or two resistors by the bias caps that help regulate preamp voltage. But my thinking was that this other 10k resistor that's connected to v2 tube right next to the preamp filter...
  11. I

    Question about jtm45

    Good to know! I think what im going to end up doing is having the 560pF across the mix resistors and the 100pF on volume but I'm gonna add 2 switches to disengage either of them for a little variety. I usually just find what works best and go with that instead of having switches and stuff but it...
  12. I

    Question about jtm45

    Ha! It's all good. What is the forum for if not to talk about this stuff lol
  13. I

    Question about jtm45

    It definitely does but it depends on the value. After 3 or 4000pF it changes the frequency response I believe instead of just more and more high end so it's a different sound. I could be wrong but I believe I read this somewhere too and my ears hear it
  14. I

    Question about jtm45

    I've got 2 amps I usually leave one of them standard 1987 spec but I have come to really love the 5000pF bright cap but i use the amp at very high volume too. I used to really like the 100pF and a few other changes when i was trying for some lead/bass spec hybrid to cover more ground but have...
  15. I

    Question about jtm45

    Ah thank you so much! I didnt know if removing that resistor would wreak havoc somewhere else if I didnt compensate somewhere or something along those lines or if I would have to do anything to the bias etc. Im not very well versed, just enough to not hurt myself.
  16. I

    Question about jtm45

    Not related to that but wondering if you could help with something else? Could I take my dual 16uF preamp filter cap and solder the positive leads together to make a single 32uF and then ditch the 10k resistor that was between the cap and install it how the first picture shows? Or would it be...
  17. I

    Question about jtm45

    So a dual 16 would be just a hair tighter than a single 16 but not as tight as a single 32uF?
  18. I

    Question about jtm45

    Honestly and I don't mean to be difficult but kind of all of the above. I use the amp through a 4x12 with everything besides the bass dimed and volume at about 9 and sometimes use it through through different cabs or with the volume ranging anywhere from 3 to 5 for pedals...it really just...
  19. I

    Question about jtm45

    Right on! Any input is appreciated though, thanks! Do you also have the 500/560pF cap over the mixer resistors in addition to your 100pF bright cap?
  20. I

    Question about jtm45

    After looking through about 20 or more pictures of various years of jtm45 amps I see they mostly have 270k mix resistors but the volume bright cap and mixer resistor treble cap seem to vary greatly if they have them or not. I'm assuming the most common volume bright cap is 100pF and that the...

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