Sony ECM-150
A condenser microphone smaller than a dime in circumference, and versatile enough that studios kept buying them by the handful.
Overview
Sony ran this pitch in the audio trade press in 1979 and 1980: the ECM-150 is an omni-directional condenser microphone, and it is Sony's tiniest mike - smaller than a dime in circumference, according to the company's own advertising. The ad copy ran in Audio (June 1980, p.21) and Modern Recording (April 1980, p.85) among others. It framed the ECM-150 as the versatile option in a lineup that included the ECM-33F, ECM-23F, ECM-260F, ECM-56F, and ECM-990F. The capsule was Sony's Back Electret condenser design, which the company claimed delivered "response truer than ever thought." That's marketing language, but the Back Electret approach was the real engineering story of that product family.
Smaller than a dime in circumference means this thing disappears on a lapel, a tie, or the fingerboard of a guitar. Sony's advertising suggested clipping it to a guitar's fingerboard or wearing it as a lapel or tie-tack mike, and noted it was well-suited to business conferences or any occasion where the microphone should be inconspicuous. That's the ECM-150: a tiny omni condenser that gets out of the way. Omni-directional patterns are forgiving of placement, which is why a microphone this small works as a clip-on. You don't have to aim it precisely. You get it close to the source and let the pattern do the work.
This is a Back Electret condenser, not a large-diaphragm studio condenser. It runs on the electret principle, which means the capsule holds its charge permanently and doesn't need the high-voltage polarization supply of a traditional condenser. That's part of how Sony got it so small. The trade-off, as with any electret of the era, is that the capsule's charge can degrade over decades. A used ECM-150 that's been sitting in a drawer since the Reagan administration may or may not still perform to spec. There's no published frequency response or sensitivity figure in the surviving documentation reviewed here, so treat any specific performance claim with skepticism and test the mike before relying on it for critical work.
Within the Sony microphone catalog, the ECM-150 is the inconspicuous option. The advertising that sold it leaned hard on versatility: clip it to an instrument, pin it to a lapel, use it for conferences. The ECM-260F handled the budget home-recording job and the larger models handled studio work. Whether it lived up to the "choicest microphones we've ever made" billing is a matter of taste, but working studios were still listing them in equipment inventories years after introduction.
These turn up occasionally in studio liquidations and estate lots, often bundled with other gear rather than sold as a standalone collector's item. There's no established collector market or price guide for the ECM-150 specifically. It's a working microphone, and it trades on utility. Check the capsule for physical damage, confirm the connector and cable are intact, and be prepared for the possibility that a forty-year-old electret has lost some of its edge.
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