Eico 378 (Late 1950s–1960s)
The Eico 378 was a stereo multiplex adapter. You connected it between an existing mono FM tuner and your amplifier, and it decoded FM stereo broadcasts. It comes from the very early wave of stereo adapters, in the first years of FM multiplex broadcasting, before integrated stereo receivers made outboard units obsolete. It was sold alongside the Scott 335 and the Fisher MPX-100, and those two, especially the Fisher, are the ones people remember today.
The 378 used a matrix demodulator and a pair of tubes. The front panel carried a Stereo-Mono mode selector with a high-frequency blend control, plus a stereo indicator lamp that lit when a stereo broadcast was detected. It was offered as a kit for $39.95 or factory-wired for $59.95. The panel-mount design suggests it was meant to be racked or installed into an existing system, not set on a shelf as a standalone piece. Audio (March 1966, p.84) mentioned the 378 in its new-products pages and described it as a sine-wave audio generator. That is almost certainly a misidentification, since the 378 is documented elsewhere as a multiplex adapter. The record from that blurb is muddled.
On performance, the research notes that early matrix-type adapters like the 378 were considered inferior to switching-type demodulators such as the one in the Fisher MPX-100. That is a period judgment, and it was a limitation of the approach itself, not of this unit alone. No owner reviews, no service manual details, no dimensions and no weight have surfaced. It is not a famous piece, and it is not the most collectible Eico product.
Known specs:
- Matrix demodulator
- Two tubes
- Stereo-Mono mode selector with HF blend control
- Stereo indicator lamp
- Panel-mount design
- Kit: $39.95; wired: $59.95
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