Turtlerock Forum

I'm in the middle of refurbishing a pair of Rola MKIII units and both input transformers have been pinched somewhere along the line.

I'm looking to order in a pair of new Jensens or equivalent, but I figured if anyone has a pair of original Rola or Trimax input transformers sitting around in the shed, it will be someone on this board.

Those wiser than me have suggested 1:4 or 1:5 transformers, but I'm open to information if anyone knows what original issue in these units was.

Thanks guys.

Probably a Trimax MS-1114. It was in the Mk II and the Mk III amp is much the same, some minor differences.
30 ohm primary, 30K secondary.
Manuals and schematics at http://www.oneillassociates.com.au/~poneill/Available_Manuals.shtml

Thanks Alastair, amazing info!

I've managed to find a picture of the back of a 77MkIII on the web, does this look like a MS-1114? The small can transformer in the bottom left corner?
I've checked out the schematic for the 77 MkII and it shows a transformer with bridges, where as the 77MkIII schem doesn't. Unsure if this is just a layout choice for the drawing, but it might suggest a different transformer.

can't see the part # on that photo. Unfortunately there a bunch of Trimax mic input transformers that are all built in the same can, so superficially look the same. I have here:
MS2458
MS2153
TA2263
173826/3
and unlabelled

...not very helpful I know

Thanks Rob- I've found a list of Trimax transformers but unfortunately none of the transformers you guys have mentioned are on there, and their doesn't seem to be any obvious logic in their designation.

http://louise.hallikainen.org/BH/uploads/TrimaxHqLowLevel.pdf

I'll keep hunting.

I have a collection of Trimax transformers and so does Dave McCluney. If you can wait 4 months I can probably dig up something suitable...

I may have exactly what you are after Alistair,
I'll email you