RCA KU-3A Single Ribbon Microphone - Very Rare

The RCA KU-3A is not a microphone you come across often. Built by RCA at the height of their engineering dominance, it lived in the great radio networks, Hollywood scoring stages, and recording studios of the golden era. It is one of the instruments that defined what recorded sound sounds like — and most of them are gone.

This one isn't. And it's been done right.

In May 2022, this KU-3A was fully serviced by Audio Engineering Associates (AEA) of Pasadena, CA, the only people on earth who inherited RCA's original ribbon technology. The work included a fresh single ribbon, a New Old Stock (NOS) KU4 grille sourced by AEA themselves, and an AEA R44 vertical case. Not reproductions, not approximations, the real parts, installed by the right hands. Invoice on file, available to the buyer.

The result is a microphone that sounds the way it was meant to and looks the part. A unidirectional, classic ribbon warmth, that proximity effect you can't synthesize. Vocals, brass, strings, guitar cab — it earns its place on any session.

This is a rare instrument in verified, documented condition. For the right studio or the right collector.