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Thread: In phase/out of phase?

  1. #1
    Axe-honerated spellcaster's Avatar
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    In phase/out of phase?

    I'm not sure if this is a solution in search of a problem, but I think it's interesting.

    Having had my setup disturbed by using the Tele bass and the 59 bassman pedal into the Twin Reverb, I was putting things back to normal. I connected the Strat to the Twin by patchcord into the Vibrato channel. Then I disconnected the cord and used the Strat's built-in wireless to connect to the Vibrato channel, adjusting the wireless receiver's sensitivity so the patchcord and wireless gains were about equal.

    Just for fun, I patched the wireless receiver into the Vibrato channel, and the guitar cord from the Strat into the Normal channel. I cringed a bit as I rolled the channel volumes up, half-expecting a honkin' big boom of feedback, or maybe a super-loud buzz......But, it sounds perfect. I didn't really expect this to work. The Strat's got the input wires for the wireless internally soldered in parallel to the input jack, so everything's in phase there. But, normally, if you try to cross-connect the Normal and Vibrato channels on a blackface reverb-model amp by putting a patchcord between them, the two channels are out-of-phase. For some reason that I'm having trouble grasping, this simultaneous guitar cord in the Normal channel and wireless in the Vibrato channel works fine....It's in phase, and what's really cool is the control....two sets of three tone controls, plus the wet reverb/dry mix.

    I'm still not sure what this means, other than an interesting science experiment, but it works against all expectations.
    "I know just enough to be dangerous....."

  2. #2
    Super Moderator die Bullen's Avatar
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    interesting experiment- I'd be lying if I said I could understand what is going on here!

  3. #3
    Axetastic doublewah's Avatar
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    I'm not quite sure what is going on either. Spell, what is different? Are you comparing your setup to a blackface? Is yours a silverface?

    But aside from phase, I wonder if the tone controls on each channel are affecting different frequencies. As in, the bass on one channel is tuned to a different frequency than that of the other channel, and/or has a different Q.
    I bought a relic'd guitar because I liked the way it sounded. Then I refinished it because I didn't like the way it looked.

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    Axe-honerated spellcaster's Avatar
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    Quote Originally Posted by doublewah View Post
    I'm not quite sure what is going on either. Spell, what is different? Are you comparing your setup to a blackface? Is yours a silverface?

    But aside from phase, I wonder if the tone controls on each channel are affecting different frequencies. As in, the bass on one channel is tuned to a different frequency than that of the other channel, and/or has a different Q.
    My amp's actually a 1070 silverface Twin Reverb, which has been had the blackface modifications, plus blackface cosmetics. It should be reacting just like a 1964 amp.

    What puzzles me is that both signals start out in phase at the guitar, which means they're still in phase when they hit the Twin's input jacks. That's the stage where I'd expect them to sound out-of-phase. Now, I know the Vibrato channel is going through it's own preamp send-reverb stage, reverb tank, and reverb recovery and second-stage gain amp, before it parallels the Normal channel st the point where they enter the power amp stage. I just don't understand why there's phase-correction (apparently) in the reverb stages.

    It also makes me wonder if the wireless is the magic piece here. In other words, could you use a wireless transmitter and receiver to chain the channels in a Fender reverb amp, and that the Vibrato and Normal channels would automatically be in phase?
    "I know just enough to be dangerous....."

  5. #5
    Axellent Member Mreilander's Avatar
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    The wireless unit or the receiver could be flipping the phase of the carrier wave, as generally, guitar signals are not phase dependent.
    Last edited by Mreilander; 11-07-2016 at 04:41 PM.

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