I use one Advanced Pressure Regulator Tube and one Advanced Pressure Gauge Tube and advanced pressure pipes so that I have the high pressure on one end of my pneumaticcraft setup, and low pressure on the other side, with the regulator tube regulating 4.5 bars into the low pressure side where the chamber is, and the high pressure side is kept at 19.5 bars with the adv pressure gauge. You just need some redstone (13) to run from the gauge to the kinetic compressor to tell it to keep the high pressure part of the system at 19.5 bars, and the regulator tube needs a redstone signal of 12 to regulate 4.5 bars to the pressure chamber and assembly line. All this stuff is explained and showed in Direwolf20's pneumaticcraft mod spotlight.
I took it further and used SFM to control the gauge and regulator tubes so that I don't have vanilla redstone all over the place.