Advice requested: Marshall + Step Up Transformer

Discussion in 'Amps/Cabs Tech Corner: Amplifier, Cab & Speakers' started by Riscchip, May 28, 2008.

  1. Riscchip

    Riscchip Supporting Member

    Messages:
    2,045
    Joined:
    Jan 4, 2002
    Location:
    Concord, CA
    Greetings,

    So looking at the print on the ancient voltage selector on one of my Marshalls, there is no 110/120 volt option. 200/210 220/230 and 240/250 are my options.

    So...I wonder if anyone could recommend a "step up" transformer (never had one of these before) for use with a 100 watt Marshall? What features / specs / ratings would I need?

    Thanks.
     
  2. Riscchip

    Riscchip Supporting Member

    Messages:
    2,045
    Joined:
    Jan 4, 2002
    Location:
    Concord, CA
    Anyone? Where did you get the voltage converter that you're using, and what specs does it have?

    Maybe a voltage converter is a voltage converter and I'm overthinking this. How about the minimum wattage rating...300, 500 for an old 100 watt Marshall?
     
  3. drgonzoguitar

    drgonzoguitar Member

    Messages:
    4,710
    Joined:
    Aug 23, 2007
    Location:
    Twin Cities
    What is the model number? What is the year of the Marshall?
     
  4. Riscchip

    Riscchip Supporting Member

    Messages:
    2,045
    Joined:
    Jan 4, 2002
    Location:
    Concord, CA
    It's a 1965 or 1966 100 watt. Not sure what the model number is...I don't recall seeing that on there, I'll check next time I'm in front of the amp, if that helps.
     
  5. stratman_el84

    stratman_el84 Member

    Messages:
    403
    Joined:
    Mar 16, 2008
    Location:
    Kalamazoo MI area.
    You've basically got a couple choices. You can buy a raw step-up transformer and put it into a box and wire it up and add the power plug and socket yourself which will save you quite a bit of money, buy a transformer that has power cords pre-wired for a bit more, or buy a unit already assembled with a 115/120VAC US-style power cord and a 220VAC European style outlet in the box for quite a bit more.

    I'd recommend a unit rated at least to 250VA for either way you go to safely power a 100-watt tube amp.

    A raw transformer I'd suggest would be something like a Thordarson 23V603.

    http://www.alliedelec.com/Search/Pr...3&DESC=23V603&R=704-0052&sid=483CA0802BC3E17F

    Or something like this Stancor P-8639 which does have an input and output cord included.

    http://www.alliedelec.com/Search/Pr...9&DESC=P-8639&R=928-4877&sid=483CA08040C3617F

    Or there's a nice deluxe unit from Hammond, the 298ET, for around $300USD.

    http://www.alliedelec.com/Search/Pr...ET&DESC=298ET&R=836-0031&sid=483CA0804727617F

    Good luck!

    Cheers!

    Strat
     
  6. Riscchip

    Riscchip Supporting Member

    Messages:
    2,045
    Joined:
    Jan 4, 2002
    Location:
    Concord, CA
    Brilliant! Thanks for the suggestions, Stratman. That's just the kind of info I was looking for.
     
  7. Riscchip

    Riscchip Supporting Member

    Messages:
    2,045
    Joined:
    Jan 4, 2002
    Location:
    Concord, CA
    Hey, quick follow up question:

    These seem generally to basically double the input voltage correct? That would mean with any of these, I'm going to actually get 240 volts from the 120 my wall has to offer?

    If I wanted to get 220 rather than 240, is it safe / okay to run my variac ahead of a step-up transformer so I can put 110 in rather than 120?

    Thanks again guys.
     

Share This Page