Using a 4 input JCM800

Discussion in 'The Squawk Box' started by Lodybo, Jul 28, 2014.

  1. Lodybo

    Lodybo Junior Member

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    I own an '80s (I think 82) JCM800 1987 (the non-master version), and it has 4 inputs. Now I generally jumper the bottom left input into the upper right one and plug my guitar into the top left one.

    Today I found this video on youtube, where the guys splits his signal into the top left and bottom right input of his Marshall (don't know which version).

    [ame=http://www.youtube.com/watch?v=fPTL9wS5XQE]Using an A/B/Y Box with a 4-input Marshall - YouTube[/ame]

    Is there a significant change in sound/volume with both inputs? I can't seem to find evidence that he uses an extra pedal in one of the chains, so it should be direct signal. At this point I'm splitting my signal to the JCM800 and a Soundman amp but this might be interesting! I haven't been able to test it because the amp is at the rehearsal room..
     
  2. Big John

    Big John So I'm standing in line at the bank, and I stick m V.I.P. Member

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    The way that guy in the video has his amp hooked up is one way to do it. Myself, I'd rather hook up both A & B to the top inputs to get the most preamp gain going from the start, and then just roll back the guitar volume on the fly if less gain is needed. Also, I'd make sure that the guitar signal is either buffered or slightly clean-boosted just prior to the ABY to avoid pickup-loading/signal-loss when in Y mode.

    I think 50w & 100w 4-hole JCM800's are some of the coolest and loudest fvcking amps on the planet. And your Soundman amp is an interesting animal. Handmade in Poland, and super rare here in the U.S. You will definitely be heard on any stage with these two amps. :thumb:
     
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  3. Lodybo

    Lodybo Junior Member

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    Both top inputs? I def need to try that one! Oddly enough, I've never thought the inputs to be so much different from each other, unlike the hi and low inputs from my Music Man.
    I think I need to try this out!

    And yes, they're incredibly loud! It sounds awesome on 50w and it's a beast at 100w. Have you ever tried one?
     
  4. Big John

    Big John So I'm standing in line at the bank, and I stick m V.I.P. Member

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    Marshall 4-hole amp designs go back to the beginning of the company, when the circuit of the first model was damn near a clone of the 5F6-A Bassman. I've been told by many old school players over the years that the main reason behind the higher/lower gain inputs for each channel on the original Fender amps was for stage monitoring purposes, where another player on the other side of the stage could patch his amp into yours and you'd be able to hear him better. If he patched into the lower gain input while you were plugged into the higher gain input on the same channel, then you'd be able to hear him just under your own instrument. This was state of the art monitoring for the 1950's because P.A. systems back then were highly inadequate. Also, the amps were played clean. Of course years later, guitar players started cranking things up and then it all went to hell.
     
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  5. Lodybo

    Lodybo Junior Member

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    Ingenious, never knew that. I picked up the Marshall today so I'm going to try this one out.

    Thanks!
     

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