The CP101 Compressor provides clean smooth compression with ultra-low noise and incredible transparency. The CP101's 4:1 compression ratio is so subtle that it's easy to forget the unit is on �?â??�?�­ until you turn it off that is. While it is on you will notice note-to-note levels that are smoother and more consistent chords and arpeggios that are tighter and more focused and when used with an overdriven amp sustain that will last for days. Best of all you'll notice minimal coloration to your guitar signal and less of the note-attack alterations so common to other compressors. At the heart of the CP101's circuit sits an HTV #P873 CdS (Cadmium Sulfur) Photocoupler. This light-sensitive component varies resistance based on the input signal to control the amp gain increasing gain as the input signal weakens. Most other current-production compressors accomplish this task using a VCA (voltage controlled amplifier) but the multiple transistors packed into a VCA inevitably lead to high noise levels which means lots of hiss from your rig. The CP101's optical circuit keeps the noise-floor low - so low that you can run the unit after a distortion and still retain near-silent operation. With its ultra low-noise level transparent operation and natural playing response the Maxon CP101 is the perfect compressor for players who hate using compressors.