JCM 800 HW Mod Andrews Amp Labs

Discussion in 'Amps and Cabs' started by Red Planet, Nov 30, 2005.

  1. Red Planet

    Red Planet Member

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    2203 Master Volume 100 watt Turret Board Construction Pics.


    Old Board. PCB

    [​IMG]

    New Board Installed

    [​IMG]


    Different Shot.

    [​IMG]


    1959 HW for a little Contrast.

    [​IMG]
     
  2. Reverend Voodoo

    Reverend Voodoo Member

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    Very Cool.

    Does it sound any different?

    What you plan on doing with the old PCB?

    :D
     
  3. hear and play

    hear and play Member

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  4. rastaman

    rastaman Member

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    Because he can! :D


    Plus, according to Jeff Andrews, the original PCB had the cheapest components on the planet.
     
  5. scottosan

    scottosan Supporting Member

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    That board is either a stock MV board from Metroamps, or its an exact copy
     
  6. Thelonius

    Thelonius Member

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    "Plus, according to Jeff Andrews, the original PCB had the cheapest components on the planet."

    This would explain why JCM800s were such road warriors.
     
  7. rastaman

    rastaman Member

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    Allright I sense a little disagreement.

    I guess I shouldn't have stated heresay as it wasn't my place.

    It's too late to delete my post but I will agree w/ an amp tech who knows the difference between a high quality component and a lower [cheaper] quality component.

    Plus, this is a REISSUE. My guess is they were trying to cut costs.
     
  8. JamesPeters

    JamesPeters Member

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    The originals had the same components, from what I recall.
     
  9. rastaman

    rastaman Member

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    Thanks James, I stand corrected.
     
  10. Red Planet

    Red Planet Member

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    Well just to clarify I asked him what this thingy and that thing was and he said cheap this and that thingy crapy. :D
     
  11. Red Planet

    Red Planet Member

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    hear and play to answer your question in the Rastaman since. I agree with his answer on this.

    I could and I did. :D

    RV sound is very minimally different. Its a great amp with the PCB and a great amp with the turret board. Plus if I want to tinker with it later on I can.

    I hadnt planned on doing anything with the board.

    Scotosan the Board is a Metro Amps Board. Jeff Andrews put it in for me. It was a bear to put it according to him. He was trying to put it in using the instructions on the disc (like I asked) only problem was the DVD had nothing on it but a boatload of nonmarked drawings and pictures for many different amps. No instructions. There were also some things on the new board that didnt match up to how the amp was set up origionally that he had to set and figure out. Thing was I wanted the circuit the same as it was in my amp. So he had to redo a couple things.

    Anyway I'm going back to bed two days without sleep is my freakin limit.
     
  12. ericb

    ericb Silver Supporting Member

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    Asides from all of that, did I miss how this sounds compared to the stock version? My 2204 I've had since about 1985 or so , is the most rugged and troublefree amp I've ever owned. I won't say many amps are built like tanks, but those are the exact words I'd describe for that one tho! Did the sound improve?

    ERIC
     
  13. Red Planet

    Red Planet Member

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    Eric the sound did not improve at all.

    Though I new that going into it.

    It is common knoledge that changing a PCB out to PTP dosnt really effect the sound very much other than the difeerence in quality in the components. There is a slight Tonal Change but I also changed the Power Tubes too.


    I wasnt going for a Tonal Change the goal was to keep the circuit as close to how it was with the PCB in it and make it a Hand Wired Amp.

    I stipulated this to Jeff before he got started. I wanted him to make sure the Circuit did not change in any way. This stipulation made things a little difficult because there were some things different in the Turret Board Circuit that had to be changed.

    Its possable that the differences were because this amp is this amp is a reissue 2203 and not an origional. That being said I told George what Ineeded the Board for.

    Its all good though. Its just a good thing a didnt attempt doing this myself. George had told me to take a look at his BB and check out who might have done this paticular kit. I looked and did a search and all I could find was some guys that had done the kit to a 2203 and thier amps werent working. When I read that I decided I wasnt going to do the work.
     
  14. Red Planet

    Red Planet Member

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    I also like the way the lead dress turned out. I see so many cool looking amps out there with 90 degree bends in the wire and I know with 480 3 phase your not supposed to do that. You put a pinch point for the electrons to squeze through.
     
  15. ericb

    ericb Silver Supporting Member

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    Hey cool thanks for the info .. It's not 'common knowledge' to me at all that it wouldn't sound better, as you said they replaced the crappy components with 'good' ones right? OR maybe that was another thread ... ?? Anyway, when you change brands of caps and resisters and even tolerances to me it changes the sound, but of course all the tolerance changes can cancel each other out and cause the sound to get right back to the starting point! Just curious , as I've heard from guys who've put Hoffman boards in their amps that really liked the results. Carry on! ERIC
     
  16. Red Planet

    Red Planet Member

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    Your welcome. Eric

    There is some slight differences to the tone though it may be from the new output tubes. I can tell a difference only slight though.

    The main things that effect tone are Output Transformers and Tubes though many other things effect it too.

    This thing being a reissue and not being a clloectable I wasnt afraid to do it. Had it been an 81 I wouldnt have. I just wanted her Hand Wired and thats it. :dude
     

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