Electro-Voice 635A (1965)
A $82 omnidirectional dynamic that a room full of studio engineers mistook for a $300 microphone - and then wouldn't give back.
Overview
Electro-Voice had a problem in 1965, and most manufacturers would envy it. The Model 635, in professional service since 1947, had become the industry's default omnidirectional dynamic, and replacing it seemed almost rude. When E-V introduced the 635A that year, its own advertising opened by asking how a microphone that good could be made obsolete at all. The answer was to make it better.
The 635A is an omnidirectional moving-coil dynamic rated at 80 to 13,000 Hz with an output of −55 dB into a balanced low-impedance load. On paper, that describes a competent broadcast microphone and nothing more. According to the company's own account, a major recording studio was loaned a dozen 635A units and asked to evaluate them blind. The engineers were given no price information, but formed the impression they were working with something in the neighborhood of $300. They cut several big band recordings using nothing but 635A's. The verdict, the best $300 microphone in the house, came back before anyone told them the actual list price.
That story is advertising copy, and it should be read as such. But the engineering underneath it holds up. The headline claim was that the 635A was better than the 635 in every way, and it rested on a handful of concrete changes. The new model was slimmer and lighter than its predecessor, with a barrel sized for comfortable hand-held work. That had not been much of a priority when the original 635 was designed. The steel case was stronger and better at rejecting hum pickup, a persistent nuisance in the television studios where the 635A would do much of its work. The finish was a matte satin chromium, chosen because it photographed cleanly under studio lighting.
The biggest change was internal. E-V built a four-stage filter directly into the microphone body to suppress pops and wind noise. That removed the need for the external windscreens that engineers otherwise had to remember, attach, and periodically replace. The same filter was designed to keep dirt and moisture out of the capsule, which extended service life in the places the 635A was built for: remote broadcasts, outdoor news gathering, variety shows, and anywhere else the microphone had to work immediately. A slip-in mount came standard, with an accessory snap-on Model 311 mount offered for desk or floor stands. E-V shipped each 635A with a Model 310A stand clamp and a lavalier neck cord, so the company clearly expected it to be used in a lot of different ways.
The heart of the design was E-V's Acoustalloy diaphragm, and the company made a bold promise about it: the diaphragm was guaranteed against failure for the life of the microphone. That guarantee sat alongside an unconditional two-year warranty covering the entire professional microphone line, which was unusually generous for the period. The Acoustalloy material was why E-V could afford those commitments. It was engineered to deliver undistorted output in sound fields intense enough to cause hearing damage. That meant the 635A could be placed inside a kick drum, in front of a trumpet bell, or against a stage monitor without meaningful risk of mechanical failure.
The market response was swift and unusually total. Radio and television news operations adopted the 635A as their standard field microphone, on the theory that news happens once and a microphone failure is not a recoverable event. Music and variety programs across the American television networks put the 635A on camera in force, mostly hand-held, largely because it sounded good at the ultra-close working distances those productions favored. E-V was candid that the original 635 would remain in daily use for years, and it did. The 635A was positioned not as an overnight replacement but as the new standard that would take over as older units wore out.
The list price of $82 was the other half of the equation. It appears consistently across E-V's period advertising - Audio (August 1965, p.59), DB-Magazine (January 1968, p.36), and Audio (December 1965, p.45) all carried the same figure. That was remarkably low for a microphone of this build quality, and it changed how studios bought microphones. A working facility could purchase a dozen 635A's and deploy them everywhere without agonizing over the budget, which is what many of them did. The same advertising that recounted the blind studio test noted that at the price, engineers could afford to use the microphone almost anywhere. Contemporary trade advertising, including a 1965 placement in Audio (October 1965, p.69), treated the 635A as a natural stocking item for any serious broadcast or audio equipment supplier - a dealer's microphone rather than a specialty purchase.
The 635A never pretended to be a studio condenser. It is a moving-coil dynamic, and it sounds like one: warm, gently rolled off at the top end, with a midrange presence that flatters the human voice. Its omnidirectional pattern picks up the room as readily as the source, and its top-end response does not compete with a large-diaphragm condenser in a critical vocal session. For close-miked speech, broadcast, and live sound reinforcement, none of that matters, and the 635A remains genuinely excellent at all three.
For collectors, the 635A is an easy one to own. The fawn beige Micromatte finish shows its age readily, and examples that saw heavy field use often have worn or chipped paint, but the microphone itself is difficult to kill. The internal filter can clog with dust over time and the foam elements inside the body degrade, but both are serviceable. A 635A that has been sitting in a drawer for twenty years will typically work the moment it is plugged in, which can't be said for most vintage condensers of comparable age. The Acoustalloy diaphragm's lifetime guarantee has aged into something closer to a historical curiosity than a practical warranty.
Sixty years on, the 635A is still doing the job it was designed for. E-V set out to replace a legend and, by most accounts, succeeded - not by out-measuring the 635, but by out-lasting it.
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