Roberts R55/Amplion "Convette" LC4

[Nick]

A lot of battery eliminators were pretty evil, at least by modern standards. I'm not surprised, they had to be built down to a price in an age when rectifiers and capacitors were expensive. LT hum had to be kept pretty low with directly heated valves. At least the earlier battery valves were a bit more robust than Dx9x types.

I'd be wary of the transformer too, but at least that can be tested with a megger.

Building a modern PSU is entirely valid, but using a rechargeable LT  cell (voltage a bit low but probably OK) and PP3s or coin cell stacks (as researched by Mike Watterson) has a lot to commend it.

I have a Megger (actually a Robin) so will test the xfrmr. I could possibly find a modern sub-miniature xfrmr, but we'll see. There's also no fusing, temp overload or actually any safety features at all... it's amazing anyone survived the '50s...