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Asher Guitars WD Music Products Amplified Parts Mod Kits DIY Nordstarnd Pickups Warmoth.com Reilander Pickups
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Silvertone organ amp 4707 anyone seen one?

Discussion in 'Amp Central Station' started by Robster, Aug 27, 2009.

  1. Robster

    Robster Tele-Holic

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    Feb 14, 2009
    Location:
    Marietta, GA
    I picked this up yesterday, no pics yet. It was an organ amp with two rca inputs to a set of tubes 12dw7(tremelo), 12ax7, 6v6GT, 5y3GT. It works now and sounds great running my MP3 player thru it but I want to convert it to be
    a guitar amp. It came with a 12 inch oxford. Tubes are all Silvertones, it has never been serviced. No filter cap hum but the tremelo is not working.
    I found a hand drawn schematic on line for it. I may turn it into a tweed champ. Anyone been down this road before?
    Thanks
    Rob
     
  2. alnicopu

    alnicopu Friend of Leo's

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    Oct 3, 2009
    Location:
    georgia
    Yea

    I picked up one for 80.00. Rewired first stage and input like a typical blackface, 100k plate load and 1.5k cathode resistor bypassed with a 25/50v sprague, 1meg to ground with a 68k input resistor. I just used an rca to 1/4 adaptor. Tried bypassing the second stage but had waaaay too much gain. Left second stage stock. Replaced all bypass caps with .02 spragues, which took away the "boxy" sound it had, really openned up the sound. Replaced another 25/50v electrolytic with a sprague of the same value. Replaced the stock Oxford with a Weber alnico sig 12 speaker (45.00 wanted to go realatively cheap since it was a project).

    Didn't have enough grind for me so I lowered the input resistor to 33k and raised the plate load resistor on the first stage to 200k, used 2 100k's in series. I would have rather lowered the last stage resistor on the filter cap to increase plate voltage but I didn't have the resistor I needed so I just raised plate load resistance. Plate load was around 165-170v before I raised the resistance (forgot to measure it afterwards).

    I may experiment more with the second stage but, since and organ amp is pretty much a bass amp, I didn't want to loose too much of the low end. Gotta get some more components to play more with it.

    I was trying to get what I wanted and still use the 12dw7, because the trem doesn't work on mine either and I wasn't sure if the extra oomph of a 12ax7 would affect the trem when I get to that. Stuck a 12ax7 there for more gain for now and I'm pretty much in Tweed territory, but I think with more minor tweeking (when I get the components I need) I may be able to do better.

    Looks like something from the old "Dick Van Dyke" show from the early 60's. Very retro looking with the wooden legs. It's kinda like an end table looking tweed champ (vibrochamp when I get the trem working).
     
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