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1976 100 watt Marshall JMP Super lead vs 1977 JMP Super lead.

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  • #16
    Re: 1976 100 watt Marshall JMP Super lead vs 1977 JMP Super lead.

    As far as this cascading/non-cascading, here's my attempt to explain it (if I'm wrong let me know). Vintage Marshalls use a 12ax7 for the gain stage, as most of you know, but for those who may not, a 12ax7 is a dual triode meaning it's two triode tube circuits in one tube bottle. So to explain how these work in these amps I'll compare it to something else guitar players are familiar with, the humbucker. Like the triodes in a 12ax7, a humbucker is two individual coils in one pickup that can be wired a variety of ways. Non-Master Volume amps are wired to use one side of the tube for each channel, like wiring up the bucker to run split. If you wanted more gain you could jumper the inputs with a patch cable and use both gain stages at the same time in parallel, just like with the pickup, it increases output (gain), but the character remains similar to using a single input. Cascading preamp run the halves of the tube in series for maximum output, this is what the Master Volume amps use (except for the first year or two of the 2204). As the amp the OP is talking about is modded it may or may not have a cascading preamp, or may be able to run either way depending on what input you plug into. Ask the seller as many questions about it as you can think of, but IMO you should buy it, worst case scenario is you end up not liking it after a while and you can sell it for what you bought it for
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    Gibson LP Trad Pro II->Various pedals->MEsa Boogie MkV->Owensby/219 Guitar Works Vertical Slant 2x12 w/WGS ET-65 and Veteran 30.

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    • #17
      Re: 1976 100 watt Marshall JMP Super lead vs 1977 JMP Super lead.

      Originally posted by themeansr View Post
      Is it me or was there no information about Marshall’s after 73 in the articles?


      Sent from my iPhone using Tapatalk Pro
      It's because 1973 was the year that Marshall switched from tag boards to printed circuit boards. After that they're all basically the same, even after the change to JCM800 cosmetics (yes, there is a 4-hole model 1959 with JCM800 cosmetics).

      FYI, Randy Rhoads' Marshall was a very late JMP 1959 that was modded. It had the one-wire mod for cascading the channels and a master volume. Nothing wrong with the later JMP NMV amps. I just wish they stuck with the smaller headshell for the 1987.
      Nope...

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      • #18
        Re: 1976 100 watt Marshall JMP Super lead vs 1977 JMP Super lead.

        Did somebody say Marshall?

        IIRC, the earliest (c. 1975) Master Volume Marshalls featured a pre-PI master volume (as opposed to post-PI).
        Last edited by LLL; 11-11-2017, 04:26 PM.
        Lefty Lounge Lizard's Guitars & Amps Extravaganza

        Fastest ears in the West

        "Where you can swap out one pickup magnet and instantly become an expert at everything."

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        • #19
          Re: 1976 100 watt Marshall JMP Super lead vs 1977 JMP Super lead.

          Originally posted by LLL View Post
          Did somebody say Marshall?

          IIRC, the earliest (c. 1975) Master Volume Marshalls featured a pre-PI master volume (as opposed to post-PI).
          I'm pretty sure all 2203s & 2204s have the master volume before the phase inverter; I don't recall ever seeing a double pot inside one.
          Originally posted by crusty philtrum
          And that's probably because most people with electric guitars seem more interested in their own performance rather than the effect on the listener ... in fact i don't think many people who own electric guitars even give a poop about the effect on a listener. Which is why many people play electric guitars but very very few of them are actually musicians.

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          • #20
            Re: 1976 100 watt Marshall JMP Super lead vs 1977 JMP Super lead.

            Originally posted by allbutromeo View Post
            As far as this cascading/non-cascading, here's my attempt to explain it (if I'm wrong let me know). Vintage Marshalls use a 12ax7 for the gain stage, as most of you know, but for those who may not, a 12ax7 is a dual triode meaning it's two triode tube circuits in one tube bottle. So to explain how these work in these amps I'll compare it to something else guitar players are familiar with, the humbucker. Like the triodes in a 12ax7, a humbucker is two individual coils in one pickup that can be wired a variety of ways. Non-Master Volume amps are wired to use one side of the tube for each channel, like wiring up the bucker to run split. If you wanted more gain you could jumper the inputs with a patch cable and use both gain stages at the same time in parallel, just like with the pickup, it increases output (gain), but the character remains similar to using a single input. Cascading preamp run the halves of the tube in series for maximum output, this is what the Master Volume amps use (except for the first year or two of the 2204). As the amp the OP is talking about is modded it may or may not have a cascading preamp, or may be able to run either way depending on what input you plug into. Ask the seller as many questions about it as you can think of, but IMO you should buy it, worst case scenario is you end up not liking it after a while and you can sell it for what you bought it for
            Thank you. Very good info.


            Sent from my iPhone using Tapatalk Pro

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            • #21
              1976 100 watt Marshall JMP Super lead vs 1977 JMP Super lead.

              Iím am going to try it out this coming Friday. He stated that it was moded by David Bray for the master Volume. This will go well with my Roadster if it works out. I really appreciate everyoneís input. Iíve been running away from Marshallís most of my life just to realize itís the Tone I have been searching for.


              Sent from my iPhone using Tapatalk Pro

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              • #22
                Re: 1976 100 watt Marshall JMP Super lead vs 1977 JMP Super lead.

                Originally posted by dystrust View Post
                I'm pretty sure all 2203s & 2204s have the master volume before the phase inverter; I don't recall ever seeing a double pot inside one.
                Right. For some reason (and that's what I thought it was) the earliest JMP MVs aren't as coveted as the later (say '77-'79) for some reason that I can't remember.

                IIRC Marshall made some improvements.
                Lefty Lounge Lizard's Guitars & Amps Extravaganza

                Fastest ears in the West

                "Where you can swap out one pickup magnet and instantly become an expert at everything."

                My Soundcloud

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                • #23
                  Re: 1976 100 watt Marshall JMP Super lead vs 1977 JMP Super lead.

                  Originally posted by themeansr View Post
                  Iíve been running away from Marshallís most of my life just to realize itís the Tone I have been searching for.
                  Never run from a (now) vintage Marshall.
                  Lefty Lounge Lizard's Guitars & Amps Extravaganza

                  Fastest ears in the West

                  "Where you can swap out one pickup magnet and instantly become an expert at everything."

                  My Soundcloud

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                  • #24
                    Re: 1976 100 watt Marshall JMP Super lead vs 1977 JMP Super lead.

                    David Bray knows what he is doing around the inside of an amp. I hope it works out for you.
                    -Chris

                    Originally posted by John Suhr
                    “Practice cures most tone issues”

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                    • #25
                      Re: 1976 100 watt Marshall JMP Super lead vs 1977 JMP Super lead.

                      Originally posted by Ayrton View Post
                      David Bray knows what he is doing around the inside of an amp. I hope it works out for you.
                      Me too. Hopefully the Mesa and the Marshall will end my tone quest.... well for at least a few months...[emoji2]


                      Sent from my iPhone using Tapatalk Pro

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                      • #26
                        Re: 1976 100 watt Marshall JMP Super lead vs 1977 JMP Super lead.

                        Originally posted by LLL View Post
                        Right. For some reason (and that's what I thought it was) the earliest JMP MVs aren't as coveted as the later (say '77-'79) for some reason that I can't remember.

                        IIRC Marshall made some improvements.
                        The real early 2203 and 2204 amps were basically the 1959 and 1987 with two less inputs and a master volume. They didn't cascade the two halves of V1 into each other but rather had them in parallel.
                        Nope...

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                        • #27
                          Re: 1976 100 watt Marshall JMP Super lead vs 1977 JMP Super lead.

                          Originally posted by GilmourD View Post
                          The real early 2203 and 2204 amps were basically the 1959 and 1987 with two less inputs and a master volume. They didn't cascade the two halves of V1 into each other but rather had them in parallel.
                          The high and low inputs also had different input impedance IIRC.
                          Originally posted by crusty philtrum
                          And that's probably because most people with electric guitars seem more interested in their own performance rather than the effect on the listener ... in fact i don't think many people who own electric guitars even give a poop about the effect on a listener. Which is why many people play electric guitars but very very few of them are actually musicians.

                          Comment


                          • #28
                            Re: 1976 100 watt Marshall JMP Super lead vs 1977 JMP Super lead.

                            Originally posted by themeansr View Post
                            I’m am going to try it out this coming Friday.
                            So what happened?
                            -Chris

                            Originally posted by John Suhr
                            “Practice cures most tone issues”

                            Comment


                            • #29
                              Re: 1976 100 watt Marshall JMP Super lead vs 1977 JMP Super lead.

                              I have seen some Marshall heads from the transition era that have 4 inputs and a stock master volume control. What are those and how common are they?. I've wondered about those for years.
                              Al

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                              • #30
                                Re: 1976 100 watt Marshall JMP Super lead vs 1977 JMP Super lead.

                                Originally posted by Ayrton View Post
                                So what happened?
                                Dude flaked out.


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