AEA R44 Series & RCA 44 Thumbnut — a single large-diameter 5/16-32 threaded swivel thumb nut, a replacement part for AEA R44 and original RCA 44 series microphones, securing the microphone body to the yoke and enabling tilt angle adjustment and locking without tools.
The thumbnut is a small-scale component with a critical mechanical function: it is what holds the microphone body — over 1.5 kg in the case of the R44 — at the set angle within the yoke. Two thumbnuts are mounted on the horizontal yoke axis, one per side, allowing the microphone to be rotated and locked in position by hand. After years of use, an original RCA 44 thumbnut in zinc or brass can seize, strip its thread, or corrode to the point where it no longer produces sufficient clamping force to hold the heavy body at an angled or horizontal position. AEA manufactures the Thumbnut as a direct factory replacement — single unit, 5/16-32 thread, large-diameter knurled head for finger tightening.
A Critical Safety Component
A worn thumbnut is a genuine mechanical risk: if the nut cannot maintain sufficient friction to hold the R44 body at an off-vertical angle, the microphone rotates under its own weight and can swing abruptly into surrounding equipment or fall. This is particularly relevant in overhead configurations where the R44 must be positioned horizontally on a boom arm, and any weakness in the angle lock manifests immediately under load. The large-diameter head allows firm finger tightening without tools — important in stage environments or when reaching around stand hardware with limited visibility.
Field Replacement Without Specialist Work
Replacing a thumbnut requires no microphone disassembly and no electronics access — the nut unscrews by hand from the side aperture of the yoke and the replacement threads directly into the same position. AEA supplies the Thumbnut as a standalone service part because it is the most frequently worn mechanical component in the entire R44 and RCA 44 assembly. For engineers maintaining a ribbon microphone fleet, keeping spare thumbnuts on hand eliminates session downtime caused by a single failed mechanical fastener.
KEY FEATURES
- 5/16-32 thread — precise fit for AEA R44 yoke and original RCA 44 yoke assemblies.
- Large-diameter knurled head — secure finger tightening without tools, even in restricted access situations.
- Direct factory replacement — full dimensional compatibility with original RCA 44 and AEA R44 yokes.
- Compatibility: AEA R44C, R44CX, R44CE, R44CXE and original RCA 44A, 44B, 44BX.
- Sold as single unit — order in pairs for complete replacement of both yoke thumb nuts.
TECHNICAL SPECIFICATIONS
- Type: Replacement thumb nut, single unit
- Thread: 5/16-32
- Head: Large diameter knurled for finger tightening
- Function: Secures microphone body to yoke and locks tilt angle
- Compatibility: AEA R44C, R44CX, R44CE, R44CXE and RCA 44A, 44B, 44BX
- Quantity per listing: 1 unit (yoke requires 2 thumbnuts — one per side)
- Country of manufacture: USA (Pasadena, CA)
