Chicago Blues Box is the amplifier brand of Butler Custom Sound, a small Illinois-based shop founded by Dan Butler. Butler began modifying tube amplifiers in the mid-1970s and eventually moved into building original designs, with the Chicago Blues Box line growing out of custom work he did for blues guitarist Anthony Gomes. The amps are hand-wired, point-to-point tube circuits drawing on vintage Fender tweed and blackface designs, voiced for blues and roots players.

The lineup has included the Roadhouse, a 4x12 combo with reverb and tremolo; the Halstead, a smaller 1x12 combo offered in 6V6 and other tube configurations; the Kingston, an 18/30-watt 1x12 built around a Tone Tubby speaker; and the Buddy Guy Signature, a 60-watt 4x10 combo reverse-engineered from Buddy Guy's own 1959 Fender Bassman and produced as a limited run of 50.

Notable players associated with the brand include Buddy Guy, who used a Chicago Blues Box prototype on the road for years, and Chris Duarte, who reportedly replaced his larger amp rig with a single Chicago Blues Box 4x10 combo. The amps are typically built to order in small numbers and are sold direct as well as through select boutique dealers.

Chicago Blues Box has 4 products cataloged on Equipboard, including Combo Guitar Amplifiers and Guitar Amplifier Heads. Their gear is featured by 2 artists, with the strongest followings in Rock and Blues. Notable users include Chris Duarte and Buddy Guy.