Western Electric 633A (1937)
The bullet-shaped "saltshaker" on a stand. It's the sound of live radio and remote broadcasts, in a 30-ohm dynamic package.
Overview
The compact, rounded bullet with three fins on top, painted medium gray. That's the Western Electric 633A "Saltshaker." Introduced in 1937, it was the first microphone ever produced in large series. That moved Western Electric from hand-built craftsmanship to scalable manufacturing, and the ruggedness stayed. Before the 633A, mics were boutique affairs. After it, broadcast and public address could scale. It wasn't meant to replace the high-fidelity 630 "Eight-ball" for critical studio work. It was the practical, reliable one.
Western Electric built the 633A at its Hawthorne plant near Chicago, and later Northern Electric built it in Canada. It was designed for more than radio studios. By 1937, microphones were spreading into schools, hospitals, restaurants, and hotels, where quality paging and public address mattered but absolute sonic perfection didn't. The 633A is a moving-coil dynamic mic with a no-nonsense build, omnidirectional pickup, and a frequency response from 40 Hz to 10,000 Hz, which was impressive for its time and application. It wasn't just for speech. Owners report it handled music with surprising clarity, and in some STAX recordings it was used upright next to the snare drum for a tight, punchy attack.
"Saltshaker" wasn't a factory designation. The name stuck because of the compact, rounded top with sound-entry holes and the three fins. The fins help amplify high frequencies and protect the capsule if someone covers the top with a hand. The original aluminum diaphragm and voice coil were glued together and handled with suction during assembly, a delicate process under a rugged casing. That casing started as two parts and later became three, which simplified production.
Specifications
| Manufacturer | Western Electric |
| Product type | moving coil dynamic microphone |
| Production years | Introduced in 1937 |
| Pickup pattern | omnidirectional |
| Frequency response | 40-10,000 Hz |
| Frequency response (with optional baffle) | semi directional between 1000-3000 Hz |
| Frequency response (Altec 633C version) | extended frequency reach of 30-12,000 Hz |
| Output impedance (original) | 30 Ohm output |
| Output impedance (Altec 633C version) | transformer for 150 Ohm output |
| Mounting thread | 5/8-24 |
| Diaphragm material (original) | aluminum |
| Diaphragm material (Altec Lansing version) | Mylar |
| Capsule dimensions | 35mm in diameter and 18mm deep |
| Optional baffle diameter | 83 mm |
Key Features
The Fins Aren’t Just for Looks
The three fins on top are functional. Besides giving the 633A its profile, they act as high-frequency amplifiers, boosting presence in the upper mids and highs. They also keep a broadcaster's fingers from smothering the capsule when he cups a hand over the mic.
Simple, Rugged, and Built to Last
The 633A was designed for low-cost production without giving up quality or durability. The casing is compact but rugged, built to survive transport and daily use in field reporting, remote broadcasts, and PA systems. A fine gauze covers the sound entry holes and keeps dust and metal particles out of the internals. The diaphragm and voice coil were extremely fragile during assembly and handled only with suction tools, yet the finished mic was anything but delicate.
Mounting Flexibility and the Odd Thread
The 633A can be mounted vertically for omnidirectional pickup or horizontally for a slight directional effect, especially with the optional 83 mm round baffle. With the baffle attached, the response is semi-directional between 1000-3000 Hz, which helps reduce ambient noise. There's a catch: the mounting thread is 5/8-24, not the industry-standard 5/8-27. Modern stands won't fit without a split-ring adapter (⅝"-24 to ⅝"-27), and original WE stands are rare. Plan on hunting down that adapter, or a 311A mount, which was sold specifically to make the 633A interchangeable with the 639.
Historical Context
The 633A arrived in 1937 as part of a major design shift in Western Electric's broadcast line, aiming for a more “modern” look. It followed the 630 "Eight-ball" by just two years but took a different approach: broad utility instead of ultra-high fidelity. The 630 was reserved for situations demanding the best sound. The 633A was for everything else - PA systems, paging, remote broadcasts, and as a reliable backup mic in studios. It became a staple at major networks like CBS, ABC, and Mutual, and even appeared in early TV broadcasts, including on KTLA Channel 5.
It was the first mic made in large series, moving away from hand-assembly, and it spread into schools, hospitals, and public venues. In 1949, under pressure from U.S. antitrust authorities, Western Electric sold its audio division to Altec Lansing, which continued producing the 633A into the late 1960s. Altec updated it as the 633C, adding an internal transformer for 150-ohm output and switching to a Mylar diaphragm. The original 633A was a Western Electric design, developed at Bell Labs and built in Hawthorne.
Collectibility & Value
The 633A comes up on eBay regularly, but don't expect bargains. It's not as rare as some vintage mics, but finding one in good condition is tough. The diaphragm is easily damaged. Scratches, dents, or a smashed-in capsule are common, as one owner noted with their own unit. Even an intact-looking one may not perform as it once did. One reviewer noted that their unit still functioned, but the thin output suggested it wasn't delivering full frequency response. These mics are nearly 90 years old.
Current listings suggest a market value around $300 USD, though final sale prices aren't always public. The accessories are the harder part. The 311A mount and the ⅝"-24 to ⅝"-27 adapter are essential for modern use, and both are rare. Without them, the 633A is a display piece. Collectors and engineers still value its role in broadcast history, its compact design, and its versatility on vocals, drums, and guitar, and it sounds as good on YouTube clips of 1964 Beatles concerts as it does on a home studio desk.
Market Value
┌──────────────────────────────────────────────────────────────────────────┐ │ WESTERN ELECTRIC 633A Nov 2026 │ ├──────────────────────────────────────────────────────────────────────────┤ │ High $258 Latest $143 │ │ Median $143 Trend — │ │ Low $87 Volume ~3/mo │ ├──────────────────────────────────────────────────────────────────────────┤ │ $300 ┤ │ │ │ │ │ │ . . │ │ $193 ┤ . . │ │ │ . │ │ │ . .│ │ │. . │ │ $50 ┤ │ │ ├─────────────────────────────────────────────────────────────────│ │ vol │▄ ▄ █ ▄█ ▄ ▄ ▄ ▄│ │ └─────────────────────────────────────────────────────────────────│ │ 2026-02 2026-04 2026-06│ └──────────────────────────────────────────────────────────────────────────┘
eBay completed sales. Excludes accessories, parts, and non-working units. Hover points for details.
eBay Listings
Recently sold on eBay: $95–$240 (median $143, based on 11 completed sales, past 12 months)
As an eBay Partner, we earn from qualifying purchases. This helps support our independent vintage technology research.
Related Models
- Western Electric 22D (1929)
- Western Electric 25B (1938)
- Western Electric 618A (1931)
- Western Electric 630A (1935)
- Western Electric 639A (1939)
- Western Electric 640AA (1938)
- Western Electric KS-12024 (1940)