"His Master's Voice" Model 1138

[thenewguy]

Picked this up at an antique/junk store this past weekend. It's in fabulous condition Don't seem to be able to find any information about this model. Made in Great Britain. One of the caps has a May/1958 date on it. Seein's as how it came from the UK, it's wired for 210-250 Volts/50-60Cycles, has a jumper plug for selecting voltages, and I was wondering if there's a simple way to step up the 120VAC I have at the outlet so I don't have to unplug my dryer everytime I want to listen to it?
Looking for a schematic if anyone knows.