Faulty Clapton Tremolux

Discussion in 'Amp Tech Center' started by Henfield Tele, May 12, 2018.

  1. Henfield Tele

    Henfield Tele Tele-Holic

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    Any ideas good people?
    Started doing this intermittently an couple of weeks ago, now the thing doesn’t fire up at all.
    So basically I can power up the amp, and the jewel light comes on, but as soon as I flick the standby switch to on I get the low level hum that it’s always had but no volume with the guitar plugged in.
    Anything obvious?
    Thanks.
     
  2. reckless meanie

    reckless meanie Tele-Holic

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    I always replace the tubes fist. Every time I have had a tube amp not function properly it’s always been the tubes.
     
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  3. Henfield Tele

    Henfield Tele Tele-Holic

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    Yes, I suspect it’s tubes. I’ve had this a couple of times on this amp and and another couple of the EC vibro-champs, so really wondered if their is anything obvious that may be a cause of the tubes failing. Never got through so many Groove Tubes and JJs!
     
  4. corliss1

    corliss1 Poster Extraordinaire Platinum Supporter

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    Is it not still under warranty since those amps aren't that old? Although I don't know what the UK warranty is I'd check into that if a tube swap doesn't fix things. If not, it's tech time.
     
  5. Dacious

    Dacious Doctor of Teleocity

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    Tried changing the second preamp tube? The Tremolux has a cathodyne second stage, which runs 12xx7 series tubes hard. Sometimes a cathodyne stage will cook a tube enough to stop it working, but it'll still work in the other preamp slot. Try swapping the two small tubes, and see if you get volume from either channel.
     
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  6. Henfield Tele

    Henfield Tele Tele-Holic

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    Unfortunately the UK warranty is 1 possibly 2 years and they won’t cover tubes. America is 5 years...go figure!
     
  7. Henfield Tele

    Henfield Tele Tele-Holic

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    It’s gone to the tech man, I think I’ll replace the whole set. Doing a tube at a time is a bit of a false economy for me!
     
  8. Paul in Colorado

    Paul in Colorado Telefied Ad Free Member

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    Let us know what the tech says.
     
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  9. Viejo

    Viejo Tele-Afflicted Silver Supporter

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    I just don't trust those push on spade connectors on the switches of Fender's new Handwired Series. That would be something to look at. They charge a premium price for those amps at least they could solder the switch connections, if for no other reason than it just looks tacky
     
  10. LudwigvonBirk

    LudwigvonBirk Tele-Holic

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    I played that amp at the San Francisco GC a year or so ago, the store guy cranked it for me (I was playing quietly trying not to disturb anybody). MiM lefty Telecaster was the only decent lefty axe on hand that I could play. Sounded great cranked up!

    I bought a rectifier tube as a courtesy.
     
  11. printer2

    printer2 Poster Extraordinaire

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    Why would the Cathodyne stage be harder on the tube than any other position?
     
  12. Dacious

    Dacious Doctor of Teleocity

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    Because it incurs a current draw between the heater and plate that exceeds the soec of 12AX7s.

    Long plate and spiral wound filaments are not recommended for this position nor no cathode follower circuits. Older tubes seemingly had no problem. This is one place the Shuguang Chinese tubes are quite good. My Excelsior was the same - even vintage longplate tubes would progressively stop working in that spot. Changed out they seemed to work OK again.

    Short plate JJ or Sov or Ruby/Shuguang were fine. My 5E3 did the same thing. Killed the wrong tubes in that spot. 12AT7s are better for that but you lose some gain.
     
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  13. printer2

    printer2 Poster Extraordinaire

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    Wouldn't a LTP or a Paraphase see the same problem?
     
  14. Silverface

    Silverface Poster Extraordinaire Platinum Supporter

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    IO always use NOS tubes in these positions precisely for those reasons.

    No - the cathodyne and cathode follower run much higher voltages on the cathode. Rule of thumb for those that can sort of refer to a schematic but don't do tech work - if you see (usually) over 100 VDC noted at one cathode of a 12A*7 tube (orthe cathode is obviously the only way for the signal to leave the tube ) use a NOS tube if you can - but if you have to use a new tube DON'T use a 12AX7LPS (spiral) or a new long plate tube. Reissues of Tung Sols and Mullards really "aren't" so don't consider them the same as NOS.

    FWIW I've had JJ's fail in cathode follower applications, so I stopped using them.
     
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  15. printer2

    printer2 Poster Extraordinaire

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    I was a little confused. My idea of a Temolux.

    [​IMG]

    I did not know they went to the cathodyne for the EC, live and learn. I hope this one is close enough.

    [​IMG]
    No voltages so I will guess that given the era that the EC Tremolux would be close to the Vibrolux voltage wise.

    [​IMG]


    OK, cathode I can see. Misplaced word, Dacious said heater and plate and I did not know why the plate voltage would be harder on the tube. Could always elevate the heater supply, it is almost automatic for me if I build an amp. I bought my first 'new' tube recently, my old stock 12AY7 tube accidentally went out with an amp and never came back. Otherwise I have enough tube pulls to do me for the rest of my building lifetime. Looked up the GE datasheet on the 12AX7, heater cathode voltage of 180V.
     
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