Classic Audio Products, Inc. (CAPI) is a Nashville-based maker of vintage-style pro audio gear, specializing in components, kits, and fully assembled modules inspired by 1970s API console electronics. The company grew out of founder Jeff Steiger's project to restore his own 1976 API model 3232 console, during which he developed printed circuit boards and sourced replacement parts that eventually became products in their own right. Originally incorporated in Illinois, the company relocated to Nashville, Tennessee.

CAPI's catalog centers on 500-series microphone preamps, with models such as the VP312 and VP312DI (recreations of the API 312 card), the VP26 (modeled after the preamp section of vintage API consoles), the two-stage VP28, and the Heider FD312 — patterned after preamps that engineer Frank DeMedio modified for Wally Heider Recording Studio 4 in the early 1970s. Beyond preamps, the company sells equalizers, compressors, summing mixers (the SumBus line), 500-series racks, discrete op amps, transformers, and a wide range of parts for builders restoring or cloning vintage consoles.

CAPI operates as a virtual storefront with no physical retail location, selling both DIY kits and assembled units directly and through authorized builders. The company explicitly notes it has no affiliation with Automated Processes, Incorporated (API).

CAPI has 10 products cataloged on Equipboard, including Preamps and Effects Processors. Their gear is featured by 7 artists, with the strongest followings in Electronic, Rock, and Folk, World, & Country. Notable users include Colt Capperrune, Oliver Ackermann, and Lorn.