CharterOak is a boutique pro audio manufacturer founded in 2002 by producer and recording engineer Michael Deming, based in Enfield, Connecticut. The company grew out of Deming's own studio work, built around the idea of making precision recording tools at a level of detail he felt wasn't available off the shelf. Beginning in 2013, CharterOak moved production stateside, handling assembly, testing, metal finishing, machining, plating, laser engraving, and powder coating in Connecticut while sourcing select components internationally.

The microphone lineup includes the multi-pattern SA538 and SA538B tube condensers, both built around an ECC83 dual triode and dual-diaphragm capsule design, along with the E700 large-diaphragm FET condenser, the S600 and S700, the M900 and M900T, and the H1000A. Each mic is hand-assembled and bench-tested before shipping.

CharterOak also produces outboard gear, including the SCL1 dual-channel compressor-limiter — a FET-based VCA design with program-dependent release curves first shown in prototype at AES Amsterdam in 2008 — the PEQ1 equalizer, and the MPA1 dual microphone preamp.

CharterOak has 3 products cataloged on Equipboard, including Effects Processors and Condenser Microphones. Their gear is featured by 1 artist, with the strongest followings in Electronic. Notable users include Luca Pretolesi.