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Old Gibson/Epiphone amps Monitor out

Discussion in 'Amp Central Station' started by xjazzy, Oct 30, 2020.

  1. xjazzy

    xjazzy Friend of Leo's

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    I recently got a 1964 Epiphone EA28RVT Pathfinder (same circuit as the Gibson GA19RVT Falcon) that I love but it sounds even better paired with my 5E3.
    I'd love to have the tremolo and reverb from the EA on the 5E3 and I can do it through the Monitor out of the EA but:
    - when I first got the EA, the amps were out of phase when using a stereo pedal to feed both amps.
    - I swapped the wires on the speaker of the EA. The amps were now in phase when using the stereo pedal.
    - The amps were out of phase when using the Monitor out to feed the 5E3.
    - I swapped the wires on the EA's speaker again and did the same on the 5E3.
    - The amps are in phase when using the stereo pedal but they're still out of phase when using the Monitor out!
    I can't understand why this would happen!
    I'm using the second input of the bright channel on the 5E3, if that matters.
    I attached the EA schematic in case someone can take a look and explain this to me. I've be very grateful.
     

    Attached Files:

  2. uriah1

    uriah1 Telefied Gold Supporter

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  3. radiocaster

    radiocaster Poster Extraordinaire

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    Stereo flangers and choruses often use phase reversal to provide a stereo effect. If that feature (it's not a bug) annoys you, then simply run the effect through only one amp.
     
  4. xjazzy

    xjazzy Friend of Leo's

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    I'm not using the effects on the pedal. Just using it to split the signal.
     
  5. Bob M

    Bob M Tele-Afflicted Silver Supporter

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    How about a Tone Bone a/b box? They seem to account for that. I've had one for years and have run many amps together without issue.
     
  6. xjazzy

    xjazzy Friend of Leo's

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    But I'm fine when using a stereo split. No need to flip the phase there. I just wanted to get the monitor out from the EA in phase and I can't understand why I can't!
     
  7. Wildeman

    Wildeman Tele-Meister

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    What about flipping the wires on the monitor out jack? I dunno, just a thought.
     
  8. tubegeek

    tubegeek Friend of Leo's

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    It sounds like the monitor out is inverted with respect to the input, and comes before the speaker out.

    You'd need to invert the monitor out somehow when passing it to the second amp.
     
  9. xjazzy

    xjazzy Friend of Leo's

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    But, flipping the wires on the speaker connection wouldn't accomplish the same thing?
    Let's say the Monitor out is +-, the wires on the amp's speaker are -+ (amp A) and on the other amp's speaker are -+ (amp B) also. Speakers are in phase but monitor out and speaker B is out of phase. I go and flip the wires on both amp's speakers and the three should now be +-, right?
     
  10. tubegeek

    tubegeek Friend of Leo's

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    This last part means that the monitor out is opposite to the EA's input. Flipping the speaker will flip both, but they will still be opposite to each other, and so when you go from one to the other, they will not match.

    You need to re-invert the monitor out so that it does not contradict the polarity of the other signal chain if you want to switch between them.
     
  11. xjazzy

    xjazzy Friend of Leo's

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    Ok, I just took another look into the schematic and I guess you're right.
    Sem Título.jpg
     
    Wildeman likes this.
  12. BuckSatan

    BuckSatan Tele-Meister

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    Make a 1/4" cable which inverts the polarity and use that to go out of one leg of the stereo pedal output?
     
  13. tubegeek

    tubegeek Friend of Leo's

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    Switch the positions of the two transformer secondary connections and you'll have what you want. The one that goes to R16 & speaker hot goes to ground, and vice versa.

    I see why you were confused, I didn't realize the monitor out was right off of the output.
     
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