JCM 800 gain mods.

Discussion in 'Marshall Amps' started by Rikochet, Mar 12, 2010.

  1. Rikochet

    Rikochet New Member

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    Well I love my jcm 800, but I would like a little more gain out of it, not so much that it sounds like a chainsaw, but just a bit more. Right now I'm just looking into all of my options. The FJA mods look pretty good, but 400 bucks sounds like alot for the mod I was looking at, and the soldano hot mod looked kinda cool, not sure how well they work though, just looking for some recommendations.
     
  2. NewReligion

    NewReligion Well-Known Member VIP Member

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  3. Adrian R

    Adrian R Well-Known Member

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    Have you tried a simple overdrive pedal yet? There is a BILLION of them on the market..
     
  4. Rikochet

    Rikochet New Member

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    yeah, I use my ts9 in front of it for leads, but to me it doesn't really sound that great for rhythm tones.
     
  5. Adrian R

    Adrian R Well-Known Member

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    **:wtf:, get a different amp..
     
  6. jcmjmp

    jcmjmp Well-Known Member

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  7. Rikochet

    Rikochet New Member

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    I love the sound of the amp, I just find that when I boost it with the ts9 I lose some of the bass and overall fullness of the sound, which I think sounds great for leads, but not so great for rhythm.
     
  8. Adrian R

    Adrian R Well-Known Member

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    *Try a different OD pedal. TS-9s in stock form can suck tone to a degree. A simple Maxon OD is far better and doesn't cut tone like a TS-9. I noticed this as well, that is cutting some of the amp's thickness, but did boost the midrange decently. There are MANY different boost pedals on the market. Many of them sound quite different. A high output clean boost pedal will do wonders for delivering more gain without sacrificing tone.

    One of the best clean boost pedals I have used was Seymour Duncan's 'pickup booster' pedal. Relatively cheap, good quality, and offers serious TOTALLY TRANSPARENT,boost, better then most, if not all others that I have tried.

    Experiment with different preamp tubes. They can have a huge impact on your amp's gain and impact characteristics. Tung-Sol 12AX7s produce quite a bit of gain as well as EH 12AX7s..
     
  9. Rikochet

    Rikochet New Member

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    hmm, I'm going to have to look into those
    I'm definentally going to look into that pickup booster, looks like it might be just what I need :fingersx:
     
  10. jcmjmp

    jcmjmp Well-Known Member

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    The tone lounge mods are very good. It might be all you all need to get your rhythm tone where you want it. You can keep the booster/OD for leads.
     
  11. Rikochet

    Rikochet New Member

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    I know, I'm just not very keen on modding something my self, as I have never really done that kind of thing before, let alone tinker with electronics at all, do you think a local luthier/guitar shop would do that kind of mod?
     
  12. jcmjmp

    jcmjmp Well-Known Member

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    local to where?
     
  13. RynoAZ

    RynoAZ New Member

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    Depending on what circuit board you have, you can swap out one simple resistor for more gain.

    On the newer models, R6 is a 10k resistor, swap it out for a 4.7k. Where I had my gain at 8 before, it's at 6 now. Putting in a 1.5k would make it insanely distorted. This resistor is #4 on the tonelounge description.

    You lose clarity though, even if you turn the knob down to compensate, so it's not just gain you... er, gain.
     
  14. ironlung40

    ironlung40 New Member

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    I use the mxr microamp for this reason....you're right about the ts9, but the mid hump that it provides works well for me for solo boost and sustain, so I use it as a solo boost only, I like my solos to bit noisy though with feedback at the ready so it works really well for that, but I would never use it for rhythm sound.
     
  15. Adrian R

    Adrian R Well-Known Member

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    Dude,
    I too own the MXR Micro Amp. I still use it for different applications. Not a bad clean boost, but the Seymour Duncan p/u booster BLOWS IT AWAY!! Far more boost..and totally transparent.
     
  16. ironlung40

    ironlung40 New Member

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    good to know, as I've been wanting a bit more gain out of it. maybe I can pickup the p/u for my boost and then run the microamp in the loop for a volume boost for leads. sounds like a plan. :hmm:

    I was thinking about an OCD, but feel like it will color my tone way too much. Any info on those?
     
  17. cudamax2343

    cudamax2343 New Member

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    Try looking into EMG's Stuff. Like a PA-2 Boost for your guitars pickups. It's a clean trimable boost upto 20dbl or just get the Duncan pickup booster pedal. Same thing but I like-em on the guitar.
    [​IMG]
     
  18. Ken

    Ken Well-Known Member

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    Yeah, a JCM 900 will sound a LOT better...

    Seriously, when is the last time you got new tubes and/or checked the bias? I can see someone saying a DSL or SLX is more suited for their music than an 800, but they should still sound really good.

    Ken
     
  19. Adrian R

    Adrian R Well-Known Member

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    :applause:
     
  20. Adrian R

    Adrian R Well-Known Member

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    What is a 'OCD'? Are you not using a MK3?? It has a boost channel! As far as running the MXR M/A in the loop..ahh HELL YA..its almost perfect for that..in fact in light of Jesta's revelation by looping the FX loop externally, I think I might try it as well. The SD p/u booster I believe would be too strong for that application in where the MXR is more laid back and most likely could be dialed in correctly to get the right boost without over driving the circuit.
     

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