An Innovator & Top Bloke to Boot! Parallel compression is the solution. a Barber innovation that blows away having to deal with attack, ratio and release knobs of other so-called "studio compressors." Barber developed a one-of-a-kind proprietary continuous “blend control” circuit, and combined it with a discrete “Class A” FET mixer circuit to allow you to continuously blend the natural signal of your carefully selected guitar with a “phase-corrected” classic compression circuit. The result? What guitar players have always wanted, unaltered attack and supernatural sustain and resonance. No studio engineering degree required.
You could also check out the Kompromat over at Madbean. Here is a quote from the build doc. “The Kompromat takes elements from both the original Keeley® Compressor and Barber® Tone PressTM and combines them into a single hybrid project.”