mc 60 transformers

[radioactive]

i saw these labels on a mc60 thats listed on ebay and was wondering if anyone could shed some light on the signifigance of these as ive never saw them before

 

[CarlV]

Cute Nothing like that on any of my transformers. New to me too.

Carl

 

[radioactive]

after some searching all i could come up was this from roger russels site"Although Mr. Mac had several other irons in the fire, such as phonograph records and museum tour audio equipment (Lectour), the most successful were the amplifiers. Later, of course this branched out into preamplifiers, tuners, receivers, speakers, etc."
so mabe this is from a museum of some sort
mabe ron or someone will know about this labeling of the transformers.
chris