Teac A-20 (c. 1968)

Little is documented about the Teac A-20 beyond a single, well-preserved period advertisement. The ad is headlined "Cassette stereo finally goes first class". It pitched the A-20 as Teac's answer to the muddy, muffled cassettes of the late 1960s, and claimed specially developed cassette heads brought the format close to reel-to-reel quality. The A-20's surviving specifications come from that page in HiFi-Stereo (August 1968, p.49):

Stereo cassette deck, AC bias recording
Tape speed: 1⅞ ips; accepts C-60, C-90, C-120 cassettes
Wow and flutter: less than 0.2%
Frequency response: 60–10,000 Hz
Signal-to-noise ratio: 45 dB
Inputs: mic 600 Ω (−70 dB), line 120 kΩ (−20 dB)
Outputs: line 50 kΩ (0 dB), headphone 8 Ω

Everything else - exact production span, original price, circuit details, independent test results - appears not to have survived. The A-20 is an early, mostly forgotten step in Teac's long cassette-deck history, and that 1968 announcement is about all that keeps it known.