Thursday, 18 June 2020

Carl Martin Plexi Tone 9v/-9v


7 comments:

  1. Oh sweeet heavenly jeebus xx

    ReplyDelete
  2. Theres a problem with the boost section but crunch and hi gain sound good.
    Would increasing the 68nf cap increase the treble?

    ReplyDelete
    Replies
    1. The boost sounds harsh and unboost like and it feels like its after the main drive? I dont know. Tbh, ive jumpered both the board boost holes and left it off.

      Delete
    2. I'll take another look at boost section tomorrow. Which op amp do you use?

      Delete
    3. I've been over the schematic again and I can't spot any errors. Boost control essentially is a gain control at the last gain stage....
      http://4.bp.blogspot.com/-ier5Qk_vR-U/Tx1MsJ0sKoI/AAAAAAAAAro/1KKJZX2vyy4/s1600/Plexitone_rev3.gif

      If you want more treble from the tone control I think you need to reduce 68nF cap.

      Delete
    4. Found another schematic that has Boost switch lugs 2 and 3 tied together. Worth trying out?
      https://s272.photobucket.com/user/harrisxr650/media/marshall%20preamp.jpg.html

      Delete
  3. Hmm. I always thought it was at the beginnening. I increased the pot to 10k, added a substantial amount and i was thinking of playing with the cap. Im gonna definatly do a dual footswitch version. I cant decided between this and the jhs @ at the moment. Marshally goodness.

    ReplyDelete