Vintage Tube Amp

For sale is a very curious piece: an Armaco TTHS4 made in Japan, likely in the’60s or early’70s. This is a stereo hi-fi tube amplifier designed for 8? Speakers, and it is unusual in being exceptionally small (7″ x 4.5″ x 3.5) and lightweight (2.4 lbs), lacking a power transformer, and having low output power (roughly 1W per channel). It uses the following tubes: 1x 35W4, 2x 35C5, and 1x 12AX7. There are no semiconductors whatsoever. I have replaced the coupling and line-to-ground paper capacitors in this unit, as well as all axial electrolytic capacitors; the multi-section filter electrolytic checked good, and so did the tone control paper caps (which have no DC voltage across them), so they were left in place. When testing this amplifier, I found it impossible to achieve low hum with normal signal sources, since the RCA jack sleeves are coupled to circuit ground through a capacitor. Ideally, input to the unit would be coupled through transformers, or an isolation transformer would be installed and the ground coupling capacitor bypassed. Output power is indeed so low that even with efficient speakers it is easy to cause audible distortion. This unit is best considered a novelty – something that one can point to and say have you seen a stereo tube amp this small? Cosmetically, it is excellent except for some minor rusting on the top cover, and dents on the decorative metal insert of the TONE knob. Thanks for looking, and feel free to ask questions or make an offer!