Difference in JTM45 and 1987x RI's w/ EL-34's

Discussion in 'Amps and Cabs' started by DirtyChains, Feb 6, 2008.


  1. DirtyChains

    DirtyChains Member

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    I have a 1990 JTM45 RI that I am thinking of putting EL-34's in place of the 5881's currently in the amp. My question is, is there much of a difference between the 2 amps tone wise other than wattage and headroom? I have listened to many 1959 amps (original and RI's) but I have never sat down and played a 1987 to compare with the JTM.

    My understanding is my amp has the good Drake transformers (saw them when I removed the chassis) and is more than capable of running the EL-34's with no mods. Is that correct?
     
  2. retro

    retro Member

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    I changed all my Tranny's for more headroom before I switched to
    EL-34's.

    Hopefully someone will pipe in here with more tech help on tranny's.

    If you are asking no mods at all besides the tranny's, I had to change one bias resistor and I changed the value on my sockets also.


    There was a large change in tone with EL34's for me. I tried a few new EL-34's and did not like them at all. Terrible IMO.

    Did however really like a pair of NOS EL34's. Really changed the character of the amp in a good way.

    But long story short due to a faulty NOS tube I had to switch back to my original bias and ended up loving TAD short bottle 6l6WGC's too much.
     
  3. 4styx

    4styx Member

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    For the amp you have,try some Sylvania Fat Boys(big bottle 6CA7's) and don't look back!They're amazing with a tube rectifier amp.
     
  4. stratton

    stratton Member

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    I'm by NO means a Marshall expert, but I owned an RI JTM45 and felt it had a good bit of Fender feel and sound to it, a sort of roundness and bigger bottom. The 1987 is more aggressive sounding: Tighter, brighter, louder, and all Marshall.
     
  5. DirtyChains

    DirtyChains Member

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    Thanks for the info guys! It was my understanding the JTM-45 RI did not need any mods to run EL-34's due to the pot having enough turns to bias correctly. I was also told the circuits in the RI amps were not that different from the 1987X RI amps-sans the tube rectifier. Did I get the wrong information?

    Any help is appreciated and more tone comments as well as tech responses would be greatly appreciated!
     

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