red, yellow and black sec. wires on MKII ot...

...what model is it?

The other amp has yellow, orange and black coding on them, as per the schematic, but the one in question is as above and I'm wondering what it's model designation might be.

Thanks in advance!

Chris Scott wrote:...what model is it?

The other amp has yellow, orange and black coding on them, as per the schematic, but the one in question is as above and I'm wondering what it's model designation might be.

Thanks in advance!

More likely that the colors faded on the one, not the other, or there was a different run of wire used on the one than the other.

http://pacifictv.ca/schematics/rmacode.pdf

This should be mandatory reading for anyone in the vintage electronics hobby.