'64 Super Reverb help! What kind of mod is this? Pics inside

Discussion in 'Amps/Cabs Tech Corner: Amplifier, Cab & Speakers' started by The Rocket, Nov 18, 2005.


  1. The Rocket

    The Rocket Member

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    Hi Guys!
    There's an extra drill on the back panel of my '64 Super Reverb. I've never plugged into it because I don't want to blow something! The other day I finally put the chassis out to take some pics. Could you please tell me what kind of mod is this?
    Thanks for your help!

    [​IMG]
    [​IMG]
    [​IMG]
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    [​IMG]
     
  2. trdlasvegas

    trdlasvegas Member

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    That's a "Line Out" mod. Useful for pluging into a mixing console.

    -Tony
     
  3. TheAmpNerd

    TheAmpNerd Member

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    I sure don't like that implementation of it though.

    So it is coming right in the feedback loop,
    and looks to be wired to the fuse socket?

    Along with the signal wire appearing to be
    right in the middle of the plug input.

    Oh and let's not forget, you have a nice ripe
    A/C line right over the direct jacks output,
    sure to inject noise.

    edit added:

    Looks like heat stress on the last output
    tube socket (closest to the rect tube)

    AND

    Is that also heat stress on the "line out"
    jack itself? The insulators are pretty black.

    AND

    Possibly the same on the Green OPT wire
    right over there by the output jack.
    There it looks kinda black, right by the
    black OPT wire. Carbon build up isn't
    so good if that is what it is.

    Double check this stuff please, hard to tell in
    pics sometimes.
     
  4. The Rocket

    The Rocket Member

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    Thanks Tony
     
  5. The Rocket

    The Rocket Member

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    Thanks TheAmpNerd. Unfortunately I'm not a tech and I'm not sure I understand everything you wrote in your post. I don't like that mod either but the amp came butchered like this already...too bad! Thanks anyway.
     
  6. Wakarusa

    Wakarusa Member

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    The placement of the mod is less than perfect (these days it'd go in the grounding switch hole). The proximity to the mains switch and fuse may induce some 60Hz hum. 'Least they tried using shielded cable.

    As for the circuit itself, picking from the feedback loop is fine. It's actually sourced from the middle of the NFB voltage divider and picked off through a 10K resistor (so the impedenace of the line-out circuit shouldn't have a significant effect on the level of NFB). The traditional install is directly off the speaker jack using a higher value resistor.
     
  7. doctorx

    doctorx Member

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    If that was my amp those brown paper electrolytics would be gone, replaced by new spragues.

    Lord knows whats happening under the doghouse.

    The ceramics would probably go in the trash, too.
     
  8. Wakarusa

    Wakarusa Member

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    Heh...

    Hey doc, can you check for swelling? :D
     
  9. doctorx

    doctorx Member

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    Yeah, upon reflection, that didn't come out quite right. :)
     

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