5E3 Clone goes mute after 5 minute

Discussion in 'Amps/Cabs Tech Corner: Amplifier, Cab & Speakers' started by constantin, Jan 26, 2015.

  1. constantin

    constantin Member

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  2. constantin

    constantin Member

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  3. constantin

    constantin Member

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  4. kevmin

    kevmin Supporting Member

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    I mean no disrespect when saying that I can see several potential issues that could be caused by lead dress, soldering technique, and grounding.

    I know that it seems drastic, because you feel that you are so close to having it in good working order. But I would go through the whole amp again, possibly even a complete rewiring. There is no need to replace any parts yet. Just make sure everything is neat and tidy with no cold solder joints. Look closely at the layout drawing from Fender as a guide for lead dress.

    I know for sure that your soldering skills and knowledge of amp layout have improved after wiring this amp. My best suggestion is to Google grounding tips for the 5E3, and make a plan for the best grounding possible. This will not involve soldering to the chassis. You are much better off with securely bolted solder terminals using lockwashers with teeth.

    Here is a link to a Victoria 5E3. This is the kind of thing you are aiming for:
    http://s643.photobucket.com/user/te...12 w Naylor 50 Watt Special/P1100905.jpg.html
     
  5. Blue Strat

    Blue Strat Member

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    ^^^ This, plus solid state (diodes) rectification may not be the best move. What's your plate and cathode voltage for the 6V6s? You may be running them at meltdown conditions.
     
  6. kevmin

    kevmin Supporting Member

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    I agree with Blue Strat on rectification too. If you do not have the real estate or transformer winding to provide a tube rectifier, I suggest a 5Y3 or 5V4 style Weber copper cap module for installation inside the chassis.
     
  7. telenut62

    telenut62 Member

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    Take some volt readings and compare to this Weber layout...

    [​IMG]
     
  8. cap47

    cap47 Member

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    I wouldn't have those two cement resistors side by side touching either!
     
  9. constantin

    constantin Member

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    I respect all of your ideas, its true i didn't care enough to work on aesthetically about chassis and its inside wiring. I measured voltages of amp, voltages are very higher than the properly working one. And what kind of sag resistors i'll need.I tried 2 parallel 470r 5w and they didn't work well.

    [​IMG][/URL][/IMG]
     
  10. Blue Strat

    Blue Strat Member

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    The voltages don't look too bad. When you consider the layout and 10s of connections that could be wrong, it's almost impossible to say where you should look first.

    I'd take a clean schematic and highlighter, and trace EVERY wire in the build while marking each connection on the schematic/layout.
     
  11. Blue Strat

    Blue Strat Member

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    When the amp goes silent make sure that all the tubes are still lit up and the voltages haven't changed.
     
  12. tomc3084

    tomc3084 Member

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    Yeah, soldering looks iffy.
     
  13. telenut62

    telenut62 Member

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    Reflow all your grounds.
     
  14. constantin

    constantin Member

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    I didn't check yet,I'm gonna try to measure tomorrow, but probably voltages doesn't stay stable when the amps working, If amps problem depends on voltage, is that mean problem related to PT or mA rate ?
     
  15. cap47

    cap47 Member

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    With those two resistors you have 235 ohms. Try 270 Ohms.
     
  16. cap47

    cap47 Member

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    I wouldn't think there is a problem with the PT. You have other issues! Throwing in parts that don't match original design isn't a good idea. Get it working before you experiment! Some of the voltages are a little high but not too far out. Make sure all grounds are good.
     
  17. PushedGlass

    PushedGlass Member

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    That's what I did with the replacement sectional cap in my PR's power supply. The original cap's solder connections to the chassis was very easy to knock loose with a chisel, those weren't good joints even before the amp left Cupertino.
     

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