Mounting an isolation transformer

[glebert]

Wanting to put an isolation transformer in this widowmaker (Melody A-3L or A-3LP maybe). I didn't look at the physical dimensions of the transformer when I ordered it, and when it came it was way bigger than I expected. Not quite sure how to mount this as the cabinet material is pretty thin, the chassis material is obviously not too stiff, etc. I do think the cabinet is plywood at least, not cardboard. The original back panel is missing, I will probably move up the lower panel to cover up the electric bits, but also open to making a new panel for either upper or lower. Any thoughts on where to put it and how to mount it?

[Enzo]

Just a thought: Mount it on the bottom. If you are afraid the wood is not enough, put a metal plate on the outside and bolt through it

[The Dude]

Agree. If not a metal plate some larger fender washers would probably suffice.

[Helmholtz]

I would mount it to the cabinet side wall just below the chassis (left side from back), so that wires don't need to be extended.

Make sure to provide some strain-relief for the mains cable.
Use a 3 conductor mains cable and safety ground the chassis.

[christarak]

Just a thought: Mount it on the bottom. If you are afraid the wood is not enough, put a metal plate on the outside and bolt through it

That's where I had successfully mounted my 240 to 110 Stepdown in my Brownface Concert for a decade or two until age caught up with me and I ordered a 240V transformer from Hammond. More years pass...and the Concert has put on more weight. Do I really need 4 speakers???

[J M Fahey]

Small World: last night finished winding a 220V to 120V *isolating* transformer for a (deceased) friend Kay 703C widowmaker.
His Son wanted it restored (already done) to use it, thatīs why I am adding this transformer.

Widowmakers are doubly so on 220V mains. Not kidding.

[glebert]

Just to close out this thread, I did end up mounting the iso transformer on the bottom. There wasn't quite enough room for it up on the side and out of view, and it is less top-heavy this way. I hate working on amps where all the pieces are daisy-chained together and is like performing surgery on a squid so I made a quick disconnect between the chassis and the iso transformer. I also made a back panel by gluing together a couple pieces of thin luan plywood and then covering with contact paper from the dollar store. It doesn't match the blue alligator print original covering but nothing was going to match that anyway.