Here's the classic DynaComp compressor from MXR. This frequently cloned and copied effect has been an industry standard since it was introduced in the 70s. It uses the CA3080 IC, which can be a bit expensive and/or difficult to source as it is a rather obsolete chip. It might be a good idea to use tantalum capacitors in the place of the 1µ electrolytic caps for noise purposes. You can mount the pots directly to the board using either long leg right angle PCB pots or these more normal ones.