Boss CS-3 Compression Sustainer Modifications

Turn your harsh, tubby CS-3 into a natural, warm compressor. Boss isn't exactly synonymous with boutique tone — this Fromel kit changes that, pushing the CS-3 into far more desirable territory. It adds clarity to chords and presence to single-note lines, with snappy pick attack and twangy, in-your-face sustain. Like a bear hug for your tone, without suffocating it.

Gone are the weak, thin, hissy stock tones — in their place, richness, depth, increased headroom, better bass response, and full body, for compression that sounds natural, clean, and warm:

• 1N34A germanium diodes replace the silicon diodes in the signal path for a warmer tone
• Every signal-path capacitor replaced with high-quality audio-grade caps for better tone and less noise
• Corrected cap values for a rich, full, noise-free sound
• Upgraded power-supply caps to run at up to 18V for more clean headroom

(Kit only — no pedal included.)

Will it fit my pedal? This kit works on through-hole CS-3s only. Boss began using surface-mount (SMD) boards on some pedals in 2017, and this kit will not fit those — check the compatibility image in the listing before ordering.

Which option should I order?

• Supreme Kit — all the parts plus detailed photo instructions. An easy project with basic soldering skills.
• Have us install — send us your pedal and we'll do it for you.

Hear it

Installing the kit yourself voids the pedal's warranty and is done at your own risk — but with basic soldering skills and the included instructions, it's an easy project.