Audio-Technica AT-605 Insulator Set
Four brushed-chrome feet, a bubble level, and the cheapest fix for a turntable that howls when you turn it up.
Overview
Twenty-five dollars. That was the ask for a package of four brushed-chrome insulators with a small bubble level tucked in. The AT-605 was never glamorous gear - it's a set of feet - but it went after one of the most stubborn problems in a home system: low-frequency vibration getting from the speakers back into the turntable and coming out again as a low howl or a muddy bass.
Audio-Technica designed the set to fit under speakers as well as turntables. The included level shows the intent was exact adjustment, not just decoupling. The insulators adjust for height and compensate for weight, which helps when you're leveling a turntable plinth or evening out a speaker on an uneven floor. The company's own advertising billed the set as handsome, practical, and effective. Marketing copy is never a verdict, but the brief is plain about what the thing does: isolate, adjust, level.
The AT-605 shows up in the period press as a real accessory line item rather than a novelty. High Fidelity (December 1976, p.140) covered the set as a new product, describing insulators that adjust for height and compensate for weight, with a level included, priced at $24.95. A couple of years later HiFi-Stereo (February 1978, p.1) ran a full equipment test report on the AT-605 Audio Insulators alongside far bigger fish - a Marantz 2500 receiver, a Sansui AU-717 integrated, a Sanyo cassette deck. That same issue's test discussion of tonearm-to-platter coupling lays out the underlying problem: when the arm and the platter are rigidly tied together by vibration, there's no cartridge output to speak of. Feet like these are the cheap, non-invasive way to break that path.
By the early Eighties the set had settled into the dealer and classified pages as a known commodity. A 1984 mention in HiFi-Stereo (December 1984, p.57) kept the AT 605 audio isolation feet in the conversation years after introduction.
What owners got was a low-tech, high-patience product. That simplicity is both the appeal and the limitation. The AT-605 won't transform a badly placed turntable on a springy wood floor. It's a mitigation, not a cure, and the period test coverage is candid that coupling problems sometimes call for experimenting with how the feet are used rather than a single correct answer. But for the price of a decent LP, it was the first thing a thoughtful dealer would hand you when you complained about feedback.
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