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Asher Guitars WD Music Products Amplified Parts Mod Kits DIY Nordstarnd Pickups Warmoth.com
Asher Guitars WD Music Products Amplified Parts Mod Kits DIY Nordstarnd Pickups Warmoth.com

5G9 Tremolux Trouble Shooting

Discussion in 'Shock Brother's DIY Amps' started by jmp81sc, Dec 4, 2017.

  1. corliss1

    corliss1 Tele-Afflicted Gold Supporter

    Sep 13, 2008
    Lansing, MI
    I thought we'd established the problem was early on in the preamp since you8 can kill the noise by shorting the bright cap?

    Pull one tube at a time, starting from the preamp, until the noise goes away. Once it does the problem is either at or before that stage of the amp.

    Yes, if lead dress were an issue I would expect chopsticking to reveal something.
     
    jsnwhite619 likes this.

  2. Nickfl

    Nickfl Tele-Holic

    707
    May 24, 2016
    Florida
    Your lead dress actually looks pretty decent to me, the heaters have some room for improvement, but the signal leads look ok, so I doubt that's the problem especially if chopsticking isn't changing anything.

    Some of your solder joints look a bit rough and I'm wondering if that isn't the issue. I'm betting on a poor solder joint or a component that got cooked, did you heat sink the components (especially caps) when you were soldering? I'd go though it with needle nose pliers and gently but firmly test your solder joints. Don't try to rip components out or anything, but you should be able to firmly pull without anything coming looose and a poor joint will break free with little force. I'm thinking it sounds like it might be a loose solder joint somewhere in the preamp grounding.
     
    clintj likes this.

  3. jsnwhite619

    jsnwhite619 Tele-Afflicted Ad Free Member

    Sep 10, 2013
    Georgia
    Yep, in probably 99% of my buzzing issues (I'll leave that 1% in case I'm forgetting something) it was always due to a bad solder joint. As stated above, if you have found the cutoff point in the preamp that kills the buzz, start working backward and check you joints & reflow anything that is suspicious.

    The last buzzing like that I had that sounds like similar circumstances was where I had apparently bumped a connection loose on a tab off the volume pot while messing with the chassis out of the cabinet. It was my 5e3. I was playing with the negative feedback or something, but when I put it back in it sounded like a beehive. Of course, the problem was nothing to do with the NFB and the area I had been working -- it was on the opposite side of the board which took a WHILE to find.
     

  4. clintj

    clintj Friend of Leo's

    Apr 4, 2015
    Idaho
    It may well be early on, but the original grounding scheme was forcing all the current from the preamp, PI, and screens to flow the whole length of the chassis, through the chassis, to get back to its source. That's a good way to make the amp both a magnet for noise and a great broadcaster of noise for the preamp to pick up.

    So, the two caps feeding the output transformer are grounded to the PT bolt and the other two are to the bus? Good deal there then.

    I've looked through a few times now, and I don't see a heater center tap anywhere, either. I don't see a green/yellow lead, or a balancing pair of resistors led to ground. Is there one there that I'm missing?

    Just trying to snag any low hanging noisy fruit here. There's not a lot of spots, relatively speaking, for noise to sneak into V1. The grid, the cathode, and the plates + wiring to the controls is about it.
     
    D'tar likes this.

  5. jmp81sc

    jmp81sc Tele-Meister

    159
    Feb 6, 2015
    Orange County
    Hello all and thanks for your feedback.

    Pulling V2, the phase inverter tube, makes the amp go silent.

    I am pretty sure it is a bad solder joint or I fried a component during install, but I can not find it. I have reflowed the joints and pulled on them and changed the caps.

    Any suggestions for testing the caps and resistors? I tried using alligator clips to temporarily attach new caps in place with no change to the buzz.

    Thanks
    John
     

  6. jmp81sc

    jmp81sc Tele-Meister

    159
    Feb 6, 2015
    Orange County
    Hey Clint,
    I thought I had a heater center tap, but looking at the classictone specs for the PT I used there is not one.

    I will create an artificial center tap and see if that helps. I did not really understand the center tap thing until now.

    Thanks
    John
     

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