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Converting UK Power Marshalls to US ?

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4/13/2006 4:13 AM

Converting UK Power Marshalls to US ?

Can anyone give me an idea of how hard/easy it is to convert "Vintage" (late 60's) Marshall Amps running on UK 220v power to run on US 110v power?

Specifically, if the amp has a the old style brown (paper wound?) style PT. Can the existing PT be rewired to a different tap configuration to run on 110v.

Or are the only choices to either replace the PT (not preferred on a vintage amp), or run it on a step up transformer (also not desireable for extended playing)?

4/13/2006 4:36 AM
Satamax	If there's no voltage selector, just use a big hefty step up trany, you'll be fine!

4/13/2006 4:52 AM
Deltablues	I just hate the idea of lugging around a additional 20+ lb piece of iron to run the amp... If those PT's don't support rewiring to US power. Is there anyone that specializes in making "exact" reproductions (both functionally and cosmetically), of early era Marshall PT's ?

4/13/2006 5:11 AM
loverocker	I hear great things about Brian's stuff over at Marstran. Is this the puppy? - http://marstran.com/T2562.htm Although if the amp is all-original, you will lose value for unsoldering wires - it's just the way amp's are valued. Not too bad if you keep the original PT, of course.

4/13/2006 6:00 AM
Chris@CMWamps	Hi Deltablues A conversion transformer is mostly used when the amp needs to be stock. Some Marshall PTs for the usa market weren't really suited for 110/115/120V/60Hz altough labeld otherwise. Imho the best Marshall exact replica iron can be purchased at MercuryMagnetics. Hope this helps, Chris

4/17/2006 2:12 PM

A 500VA step-up/isolation transformer is a cube of iron less than about 6inches across.

Lighter than a car battery but heavier than a breadbox, packed with power they really satisfy

No, I'm not selling mine.
But they are cheaper than a reguar PT so I expect they are insignificant in cost compared to a custom PT. Mine was free anyway, there is a lot of surplus around.

Plus you only generally need only one to last you a lifetime, and you can use it on other kinds of equipment from a number of other countries. So it might be a good idea to scrounge one up for the time being if nothing else so you can delay the decision to do elective surgery.

Mike

4/17/2006 2:58 PM

I don't recall seeing many, if any 50 or 100W heads from the 60's & 70's (in the USA) that didn't have multi-tap PT's. You will need to open it and see if there's a bunch of un-terminated colored wires coming from the PT primary and chose the tap that gives you the closest to 6.3V on the heater supply. you can probably consult the Marshall schematic archives on the internet to get the color codes for the various taps.

RE

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