A friend got two amps from a old repair guy for me to fix up, one a Supro 1606, the other one is the mystery amp...It has date codes from 1959, looks well made and runs a 5y3gt, 6v6gt, 6v6gt, 12ay7, 12a7y tubes. Has a service tag on the speaker from 1965, I think the speaker is not original. No idea who made this one. Has unique number plates under the controls which go all the way to 15! Anyone got a clue on this one? Thanks!