Altec 359A (1961)

The Altec 359A is an FM stereo multiplex adapter, sold under Altec's "Stereoplex" name. It showed up in print advertising in the fall of 1961 as a simple, set-and-forget unit for decoding stereo broadcasts. Audio (October 1961, p.57) ran a full-page ad that called the 359A an adapter you could "plug in, set … forget," and said all the controls needed for stereo reception were on the front panel. The price was $89.50, cabinet included. A companion ad in HiFI-Stereo (October 1961, p.29) used the same price and the "Stereoplex" name. Other placements paired it with the Altec 353A stereo amplifier-preamplifier.

Beyond the advertising record, little is documented about the 359A’s internal circuitry, specifications, or production run. It likely used the tube-based multiplex decoding circuits common to the era, but no schematic, service manual, or technical review has been located. The adapter is one of several Altec components from the early 1960s that were sold as part of a complete stereo system — the ads often placed it alongside Altec’s full-size speaker systems and the 353A amplifier. No collector pricing, user impressions, or service notes have turned up in the Archive’s research.

Known details:

Model: 359A “Stereoplex” FM multiplex adapter
Introductory year: 1961
Original price: $89.50 (including cabinet)
Claimed feature: all stereo controls front-mounted; simple installation and operation