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Handwired amp. Golden tone, but with issues.

Discussion in 'Amp Central Station' started by Joebloggo400, Apr 14, 2021.

  1. Joebloggo400

    Joebloggo400 TDPRI Member

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    Hi there,
    I've recently acquired a vintage handwired amp.
    10 inch speaker, based - I think - on some sort of fender, although I can't pinpoint the exact model, and I'm starting to think it might be a custom design. Intrigued?

    The amp gives me the tone I've been dreaming about. Fast response, long sustain, spring reverb, breaks up like a old deluxe.

    But there are problems.

    Only the treble pot seems to work properly, the bass pot cuts out at 2 and never changes from then on.
    The mid pot does nothing. Sometimes the master pot goes from mute to extremely loud, sometimes it doesn't even cut sound at 0. And after about 20 mins of being on, it triples in volume, not nice when playing at night in a house with 13 people. (I live in a commune!)

    My question is, can anyone identify the kit? I'm looking for schematics. I think it came from Poland, and was built in 2000. And any amp wunderkinds out there that could diagnose the issues I mentioned would be much appreciated.
    I would like to try repair it myself. I know nothing but my housemate knows his stuff..
    Maybe new pots, but any other tips of mods would be great to know.

    I play a 68 tele with a PAF through this thing, and I am one happy, happy papa of these kids.

    Looking forward to hearing from you guys!

    [​IMG][​IMG]
    [​IMG][​IMG]
     
    Last edited: Apr 14, 2021
    BB likes this.
  2. 68tele

    68tele Friend of Leo's

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    You should post pics, lots of detailed pics
     
    ce24 likes this.
  3. Joebloggo400

    Joebloggo400 TDPRI Member

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    Oh my mistake, I just added them
     
  4. jmp81sc

    jmp81sc Tele-Meister

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    This will be difficult and time consuming. You will need to trace out the circuit and create a schematic first, then start trouble shooting. You can do the obvious things like tube swaps, clean the tube pins and pots first, maybe change out the electrolytic caps.
     
    Killing Floor likes this.
  5. Killing Floor

    Killing Floor Friend of Leo's

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    Agree, try cleaning the pots. Note not to be selective with any cleaners and go very lightly. Another thought for later is that if you can match a pot replacement with identical spec would be a reversible mod if needed. If you use something like Deoxit go really lightly. Don’t live by my advice because I’m a moron but let a few posts pass to see how this stands. But I’ve had some success with very light use of Deoxit. Pots can fail for a lot of reasons. If it does nothing like your mids (?) it’s probably not dirty. But a pot that scratches or skips can often be restored. If that fails pots are surely available of same spec.
     
  6. DrPepper

    DrPepper Friend of Leo's

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    Sounds as if the wrong type of pots were used (audio taper vs log) and questions the circuit design (mid control). Also, there may be some bad solder joints.
     
  7. dan40

    dan40 Friend of Leo's

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    Sounds like it could also be a cold solder joint in the tonestack or ground connection. Being a kit amp, it is very possible that one or more solder joints may need touching up.
     
    teleplayr likes this.
  8. CapnCrunch

    CapnCrunch Friend of Leo's

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    That is a tag strip build, so not far off from a true point to point build. I don't know of any kits, at least available over here in the States, that use tag strips solely. My guess is that someone built this as a one off. I can't see the details well enough to evaluate the circuit or even assess the quality of the solder joints. More high def. and close up photos of the entire interior of the chassis would definitely be helpful.

    Based on the OP, I am guessing that you don't know how to discharge capacitors. If you don't, be very careful about sticking your hands inside the chassis (as in don't do it), you could get bit very hard. Have your housemate help, or take it to an amp tech to help diagnose and fix the problem.
     
  9. ArcticWhite

    ArcticWhite Tele-Afflicted

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    Can't tell a thing from those pics.
    Turn on the lights, clean the lens, or use a decent camera.
    You need to post a full gut shot, and three overlapping closeups.
    And as stated above, the big capacitors can store 400 volts, even unplugged. Keep your hands out.
     
  10. Joebloggo400

    Joebloggo400 TDPRI Member

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    Sorry for the delay, here are some detailed pics

    DSCF4250_3.jpg DSCF4249_3.jpg DSCF4248_3.jpg DSCF4246_3.jpg DSCF4245_3.jpg DSCF4244_3.jpg DSCF4243_3.jpg DSCF4242_3.jpg DSCF4241_3.jpg
     
  11. Joebloggo400

    Joebloggo400 TDPRI Member

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    Some more, sorry if too many pics, it's tricky to capture everything properly. DSCF4254.jpg DSCF4253.jpg DSCF4252.jpg
     
  12. Wally

    Wally Telefied Ad Free Member

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    You are going to need a good tech IF you want to understand what is there. As suggested, one would want to draw a schematic of what has been built. Due to the type of chassis that was used, it is very difficult to see the circuit from pictures because the tube sockets and control pots cannot be seen in one shot.
     
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  13. ArcticWhite

    ArcticWhite Tele-Afflicted

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    You're going to need to take this to a tech. This is not a good project for a beginner.
     
  14. Joebloggo400

    Joebloggo400 TDPRI Member

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    Ah too bad, but your totally right. Thanks for your advice!
     
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  15. ce24

    ce24 Poster Extraordinaire

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    It needs a 3 prong mod! Thats all i got lol.
     
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