Hi, I’m looking to build a SSL style bus compressor, ideally as a kit, but I’m fine sourcing parts. I only know of the Gyraf version. Is there a more updated version, ideally with a side chain HPF?
If you want it in a 1U rack format then you should try to buy a Serpent Audio SB4000 PCB,
they don't sell the PCB anylonger but that was the best PCB for these project, it had all the extra features included.
Ask in the black market, I'm sure there's many people with PCBs in the drawer that will never use https://www.evolutionarytheory.com/tag/sb4000/
If you want in the 500 series format, then go for the Sounskulptor like Ruud advised
The sound skulptor unit looks very good, but I don’t have much outboard gear and haven’t jumped to the 500 format yet. I understand it’s appeal but it’s not for me. I think I will probably go with the gyraf PCB and build it from there.