AuroraCompressor / Sustainer

From the vendor

The original guitar compressor, still a favorite of guitarists after over 40 years. The Aurora makes several improvements to the original circuit as well as adding a few new features.

Note: This project uses a type of capacitor that has been temporarily discontinued by WIMA. Please see our news article about the issue and the substitution spreadsheet for project-specific recommendations. We are stocking an equivalent from Kemet in the mean time. The build document has not yet been updated to reflect this.

Project overview

The Aurora Compressor/Sustainer is an updated version of the MXR Dyna Comp and the Ross Compressor. One of the first compressor circuits designed for guitar, the MXR Dyna Comp has been a consistent favorite among guitarists, and the circuit is legendary in the DIY community.

The Ross Compressor was an updated clone of the Dyna Comp that got a lot of attention when it was “rediscovered” in the 1990s by Trey Anastasio of Phish. It has better power supply filtering and thus lower noise, but is otherwise very similar to the Dyna Comp.

The Aurora takes things a step further by adding a couple of modifications. First, the obsolete CA3080 has been replaced by the LM13700, which is essentially just a dual CA3080 but with the advantage of still being in production and easy to find.

The output section has also been modified to take the signal from a different part of the envelope detector. This results in drastically reduced ripple (which is perceived as distortion on the otherwise clean signal). Some people like this distortion, so the Aurora was designed so you can still build the “stock” version and use the classic output stage. See the build notes in the PCB-only documentation for more details.

Note: The PCB-only version of this project uses a type of capacitor that has been temporarily discontinued by WIMA. Please see our news article about the issue and the substitution spreadsheet for project-specific recommendations. We are stocking an equivalent from Kemet in the mean time. The build document has not yet been updated to reflect this. It does not impact the kits.