Marshall EL34 100\100 vs JCM800 power amp section

Discussion in 'The Rack Space' started by Nickerz, Sep 14, 2018.

  1. Nickerz

    Nickerz Member

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    How close are they in terms of color\flavor and tone? I'm trying to use a JCM800 as a power amp and frankly, the amount of work and money involved to accomplish this is fairly substantial. If I can get 95% there I'd go with a 100\100.

    Did Marshall really try to "demarshall" the 100\100 or is the flavor there? How does it differ from the JCM800?
     
  2. George71

    George71 Member

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    Should sound pretty close, would also recommend taking a 100/100 instead of drilling holes into a mighty JCM800
     
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  3. Jack Luminous

    Jack Luminous Member

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    I had this done years and years ago to my 2203 : tube effect loop with the additional tube mounted inside the chassis. Send/return are on ring/tip of a TRS jack socket for insert just like a studio console channel insert or plug a normal TS cable directly to use only the return of the loop and thus use the head as a power amp easily. My local tech asked about $150 for the work (20 years ago). Sounds great. The 100/100 sounds great too but I guess it would be more expensive.
     
  4. Nickerz

    Nickerz Member

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    They're about the same price at this point, that's why I'm curious!
     
  5. Coalface1971

    Coalface1971 Member

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    Not so sure about this, it's comparing apples to oranges as both are a different topology and intended for different applications. I'd have to ask myself what defines the power amp "sound" of the 800?

    Here is my experience. I had a '76 JMP 2204, and an EL34 50/50, unfortunately not at the same time. I thought the EL34 50/50 was pretty smooth and polite sounding regardless of the preamp used, and like a lot of stand-alone poweramps I've tried/owned, its input circuitry was easy to overdrive, maybe easily perceived as a limit in headroom. The 2204 was very aggressive and in the face, loud-as, bog stock by the way except for a switchable bright cap mod.

    But again, apples vs oranges imo. An amp that is a complete integrated system (800), vs the poweramp needing an external preamp (interfacing of two systems).

    A lot the sound change from the 1959/1987 circuit to the 2203/2204 was a change in preamp. More gain and the cold clipper in the MV 800's. Not to the degree of say an SLO, Recto's etc. or modern designs, however lot the sound of the MV 800's is in the preamp. There too many other variables introduced.

    The circuit of the EL34 poweramps are tailored a lot differently than the power section of a basic Marshall head. There is a lot more circuitry and stuff going on to allow them to interface with different preamp ideas. And it's generally accepted that another interface stage - like an effects return - is required to use an external preamp into a stock amps power section. It's hard to get it to sound, play and feel exactly the same, as you don't really "hear" exclusively, the "sound" of the 800 power section.

    Guess you have to experiment.
     
    Last edited: Sep 14, 2018
  6. Dave L

    Dave L Member

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    The old black 9000 power amps that are four rack spaces are the ones to get, not the more recent gold stuff. Often cheaper, too.
     
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  7. Coalface1971

    Coalface1971 Member

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    Nice Dave,

    Apparently these sound a bit different (subjective of course), though as long as ventilated well, electrically these old black ones (9005) are interesting.

    The 9005 circuits have a post phase inverter drive section, which has more in common with a Marshall Major than typical Marshall PA Plexi/800 power section.

    I'd like to try one out, as they seem to couple the preamp directly to the PI, which from my experiments is very preamp dependent. But the post PI driver stage would make that sound different.
     
  8. Mark Robinson

    Mark Robinson Member

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    A JCM 800 2210 already has a loop return in it and is nicely compatible with rack gear.
     
  9. Nickerz

    Nickerz Member

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    Do Marshall offer a JCM800 flavored power amp? Is the EL34 100\100 JCM800 style?
     
  10. killerburst

    killerburst killerburstguitars.com Silver Supporting Member

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    John Suhr, IIRC, cited the Mesa 2:90 as the most 2203-like power amp in rack format. When he developed the 3+ preamp he used the 2203 power section as the baseline but said the Mesa came in right behind it. Again, IIRC. @Husky I hope I’m not putting words in your mouth.
     
  11. George71

    George71 Member

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    True, but the EL34 100/100 came out after the 2:90
     
  12. kingbobalou

    kingbobalou Member

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    I had one of the black Marshall 9005 power amps
    back in the 90's rack days. it was 50 watts per side in "dual mono" configuration or could be manually bridged to mono for 100 watt mono operation. There was definitely a lot more circuitry in the 9005 than in a JCM 800 power amp section. I never compared it side by side with an 800 but I can say the 9005 sounded great and very "Marshally." Of course it was dependent on what preamp you had in front of it. I can say that if I put a Plexi sounding preamp in front of it the output sounded very plexi and if I had an 800 style preamp in front of it it sounded very 800 to me and just excellent overall.

    It definitely had a Marshall "flava" in spades if that's what you're looking for, though I couldn't say if it's "exactly exactly" the same as an 800. With a good Marshall style preamp in front it was a beast though, I can say that.
     
  13. Jack Luminous

    Jack Luminous Member

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    I read that as well on HRI in one of his post years ago. Even before that, I stopped using the 2203 power section when I bought a 2:90. Still using the 2:90 to this day.
     
  14. iam_krash

    iam_krash Supporting Member

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    Truth! Those gold marshall power amps are thin and wimpy. Find yourself a clean, used VHT 2/50/2...DONE! Last power amp you'll ever need to buy
     
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  15. teofilrocks

    teofilrocks Supporting Member

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    If I had the rackspace and the money, I’d go on the hunt for a VHT 2150. Boom.
     
  16. Canon

    Canon Supporting Member

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    I owned 2 of the gold 9200's w/the 5881 output. I wold agree with thin and wimpy, but just let me add that they looked fantastic in the rack. The Mesa 50/ had the tone.
    I now have the VHT 2/50/2 and would go for the 2150 if weight wasn't a factor.
     
  17. WhiteStrat

    WhiteStrat Supporting Member

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    I had one, wish I still did. Currently running a Mesa 2:90. The Marshall was just killer. Warm, a little softer feel. If I could trade my 2:90 for one I would. Nothing wrong with the Mesa it’s just different. 6L6 vs EL34.
     
  18. Nickerz

    Nickerz Member

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    JE SUS CHRIST this 2:90 is loud. Mah ears. Gonna need a 100\100 to go with it for the EL34 stuff.

    Goin' tube rollin' next week!
     
  19. teofilrocks

    teofilrocks Supporting Member

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    Pretty sure the 2:90 can swap certain 6L6 tubes for EL34.
     
  20. Nickerz

    Nickerz Member

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    Yup, can swap the outside tubes for simulclass. Will be putting in some 6AC7s. I've decided to use the amp just for 6L6 relevant models for amps that use the 6L6 family. Will be searching for an EL34 100\100 for Marshall and vintage sims.

    I don't buy the idea of using 6L6s to model EL34 amps. You can feel it. I understand the other "model" PAs like the Randall etc are designed around it but I don't buy it.
     

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