Social Entropy is a small American electronic music instrument company based in Allen, Texas, in the Dallas-Fort Worth area. The company designs and assembles its hardware in the USA, working with local suppliers for PCB assembly, metalwork, screen printing, and packaging.

The brand is best known for two product lines: drop-in CPU replacements for vintage Roland gear, and the Engine standalone sequencer. The Quicksilver 303 and Quicksilver 606 are firmware-replacement CPU mods that update the operating systems of the Roland TB-303 bassline synthesizer and TR-606 drum machine, adding modern sequencing features while preserving the original analog voices. Engine, introduced at the 2015 NAMM Show, is an x0x-style multitrack hardware sequencer with eight polyphonic tracks, grid/realtime/step recording modes, and a built-in mini-keyboard. An optional CV Output Expansion board adds sixteen CV/Gate outputs (eight pairs configurable for V/Oct or Hz/V pitch, control voltages, or triggers) for driving analog synthesizers, modular systems, and drum machines.

Social Entropy occupies a niche in the boutique sequencer and Roland-mod market, with the Engine in particular gaining a following on community forums such as Gearspace and Mod Wiggler among hardware-focused producers who want a dedicated sequencing brain for MIDI and modular rigs.

Social Entropy has 2 products cataloged on Equipboard, including Audio Sequencers. Their gear is featured by 2 artists, with the strongest followings in Electronic and Rock. Notable users include Richie Hawtin and Bon Harris.