Extract from 1960 DeArmond Amps Catalog:
R5T Example 1, Ser. No. L0760: DeArmond R5T amp (x):
R5T Vacuum tubes Layout and Serial No. label:
Chassis (3 photos):
DeArmond logo on speaker grille:
Example 2, Ser. No. MK0537: Martin M110T amp (A0166).
Tubes layout and Serial Number:
Control panel Layout:
Chassis Interior. Note replacement speaker:
Serial Number MKO 537 on chassis:
Front view of amp with model number in white-fronted black plastic:
Front view of amp with model number in white-fronted black plastic.