[g8wayg8r]

Thanks for both ideas. One is very simple but offers the least flexibility. Read about bucking transformers. Simple in concept but the wiring is a tad odd at first.

Wire the two transformers together to get two nodes. The transformers should have the same VA rating.
Node one is an isolation secondary, one bucking primary and one bucking secondary.
Node two is the other isolation secondary and the other bucking primary.

There's an unattached bucking secondary. This is connected to the radio.
Node two is connected to the radio.

If the voltage steps up (not down), just reverse th bucking secondaries. Got the 130V down to 115V using a 6.3-0-6.3 center tap transformer (with the CT unconnected).

Now to make a circuit without a variac that will allow me to step up voltage in reasonable increments when I power up a radio for the first time. Guess it wouldn't hurt to have an amp meter in line.