Sherwood S-3300
A tuner that promised 0.15% distortion and got the heart-transplant lab to agree — for under two hundred dollars.
Overview
The number that jumps off the page is 0.15% — Sherwood's claimed distortion figure at 100% modulation, the headline of the S-3300's entire pitch. This was the company's first FM stereo tuner built around integrated circuits, and the marketing leaned hard on that spec, pairing it with field-effect transistors in both the r.f. and mixer stages to keep spurious responses down in strong-signal territory. Whether or not the low-distortion claim was the reason, Sherwood's advertising noted that the company's tuners had been picked to receive telemetered EKG data in heart-transplant research programs — an endorsement no spec sheet can manufacture.
The rest of the published numbers are respectable rather than spectacular. IHF sensitivity was quoted at 1.5 µV at 30 dB quieting in the period advertising, as Audio (November 1965, p.20) reported. Crossmodulation rejection was quoted at -95 dB, stereo separation at 35 dB, and hum and noise at -70 dB. Stereo frequency response was given as 20 to 15,000 Hz, ±0.5 dB in the later spec block. None of these are state-of-the-art figures for the era, but they are honest ones for a tuner that sold for $167.50 in the mid-sixties and $197.50 less case by the time the 1968 notices ran.
Hirsch-Houck Laboratories, whose findings Sherwood quoted in its own advertising, measured usable sensitivity at 1.8 microvolts and an ultimate distortion level of -48 dB — a result the lab described as "just about as low as we have ever measured on an FM tuner." That testimonial is the strongest independent evidence in the record. It is worth noting the lab tested a tuner, not necessarily this exact serial, and the claim is repeated across several 1968 ads rather than a single review — collectors should treat it as a manufacturer-cited measurement, not a fresh bench test.
The feature set is where the S-3300 earns its keep. Automatic FM stereo/mono switching, a D'Arsonval zero-center tuning meter, interchannel hush, a front-panel output level control, and a stereo noise filter that Sherwood claimed reduces high-frequency background noise "without affecting frequency response." The Synchro-Phase FM limiter and detector, built with microcircuitry, was the technical centerpiece. The chassis measures 14" wide, 4" tall, and 10¼" deep — shallow enough for a shelf, wide enough to look serious. The tuner was sold without a case at $197.50, with a walnut-grained leatherette case at $7.50 or an oiled-walnut wood case as the upscale option.
The integrated circuits are the wildcard — early ICs are not always replaceable, so a dead S-3300 is often a parts unit.
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