A beat to crap 1971 Super Reverb chassis needed a new lease on life

Discussion in 'Amps/Cabs Tech Corner: Amplifier, Cab & Speakers' started by CDA, Apr 11, 2015.

  1. CDA

    CDA Indigenous Donkey

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    So.

    A beat to hell 71 SR chassis came straggling into the shop a little while back.

    Removed all of the circuit flaws. Obviously, right? Tweaked the dry channel for something usable, something with a little ass, and verb. Sorted out the "Vibrato" channel. Caps, parts, caps, parts, proper values for results etc..

    Matched up a new output box so we could assume a 4 ohm-ish load. A face plate. A couple cabinets :console

    And a 15 inch bangerang commonwealth driver. Mounted the pan in the cab ..
    As you can see, Johnny settled on chicken head knobs instead of the OEM knobs. Shame is we threw out the original knobs in a pizza box by accident. But the pizza was tasty!
    Blonde worked out pretty well I think!

    Our Tone Philosopher cab kicks serious ass, but this was a one off job for a long time regular. It's not for sale. This isn't an ad.

    Just amp porn

    My cell cam seams to bend strait lines !! :roll

    [​IMG]

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  2. damian1

    damian1 Member

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  3. mxvin

    mxvin Member

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    very nice.....love the SR platform. I did a Vibro clone off of a Bandmaster Reverb and used a single 15 Altec 418B ( I think...lol). One of my fave amps. Enjoy!!

    lets hear it
     
  4. fenderpro

    fenderpro Member

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    beautiful job. any chance of a recording or video to go with it?
     
  5. pdf64

    pdf64 Member

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    Looks great!
    Did you tweak the global feedback to maintain the same ratio for the 4 ohm load, compared to as it was for the 2 ohm load?
     
  6. schmidlin

    schmidlin Member

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    Dang Adam, no 'before' pictures??
     
  7. SamBooka

    SamBooka Member

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    and no beaver shots..
     
  8. CDA

    CDA Indigenous Donkey

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    Actually the amp has variable feedback. However, now you mention it I'm not so sure there is a difference anyhow. What is it if memory serves in my drunken state. Output box voltage, across driver, through a 820 ohm resistor with a voltage division of 100 ohms to ground. Right?

    Hell, I massage the LTP anyways. I was at 500pf input and .022s to the grids of the finals.

    I did smother the screens with 1K screen grids, but with a bright and clean driver, this is sort of a necessity. Who needs 50ish "clean" watts on a 103db or whatever it is 15 inch speaker in a big ass cab right!

    I wish I was able to play her in the man room right now. She sure was sweet. But she's home until something blows up I figure..
     

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