Bubblesound Instruments is a Eurorack module builder founded by David Wagenbach in 2008 and based in Portland, Oregon. The company's design philosophy centers on using period-correct op-amps and transistors from the 1960s and 70s to faithfully recreate the character of classic analog synthesizers like the Oberheim SEM, ARP 2600, and Korg MS-20.

The lineup focuses on filters, oscillators, envelopes, VCAs, and utility modules. Signature designs include the SeM20, a 2-pole state-variable filter based on the Oberheim SEM with the resonance section of an MS-20 grafted on, and its stereo variant the SeM20st. The VCOb is an analog oscillator noted for an unusually wide frequency range, while the HEXa(s)r packs six independent AR/ASR envelope generators with mixer sections into 9HP. Other modules in the range include the LP40 and HP40 filters built around SSI2140 chips, the SpringVerb analog spring reverb driver, the uLFO, the Mix6 mixer, and the Booster and Reducer level-matching utilities for interfacing line-level gear with Eurorack.

Many modules are offered both pre-built and as DIY kits, and the brand is distributed through modular specialists including Modular Addict, Big City Music, Control, Midwest Modular, and Nightlife Electronics.

Bubblesound has 8 products cataloged on Equipboard, including Modular Synthesizers. Their gear is featured by 2 artists, with the strongest followings in Electronic. Notable users include Richard Devine and BT.