At 122-123VAC your voltage is perfect, and it will be essentially the same at the Bryston's output.
Bryston Bit 15
I was considering trying a Bryston Bit 15 IS(just the isolation transformer) but I'm wondering if the voltage output would be too high given that the input is usually around 122-123v. If anyone is using one in their system and could compare the input voltage to the output voltage I would appreciate it.