Being solid state, the Sunn Concert series does not have an output transformer. It does however have a driver transformer (10 wires) that can be obtained from Mercury Magnetics. There are two different power transformers that were used. The first has 8 wires, the second has 5 wires. To replace the first type would probably take a re-wind, a custom made transformer or 3 off the shelf transformers. You can probably find an off the shelf replacement for the newer 5 wire unit. For Power transformers, comments apply to 120V 60Hz units that were intended for use in the USA. I'm not aware of any units with universal primaries or 220/240V 50Hz units that may have been made for export.