Harman Kardon 20

Not much is documented about the Harman Kardon Model 20. The model number shows up in period literature as "20/2o" (likely "20/20"). High Fidelity (March 1955, p.102) said it was intended specifically for home recording use. That makes it a specialized component for the enthusiast who wanted to record at home. Past that one reference, the record is empty.

The same source recorded these specifications:

Price: $189.50
Dimensions: 13⅝ × 7 × 11½ inches (width × height × depth)
Distortion: 3% IM at 20 watts
Damping factor: 22
Tube complement: 6U8, 2×12AT7, 6BE6, 6BA6, 2×6AU6, 6AL5, 6AB4, 12AU7, 2×5881, 6X4, 5V4
Manufacturer: Harman-Kardon, Inc., 520 Main Street, Westbury, N.Y.

The pair of 5881 output tubes points to a tube power amplifier or integrated amplifier from Harman-Kardon's early years. No production run, power output rating, or further design context has surfaced. It remains one of the more obscure entries in the brand's history.