The Park P50M is the first split cathode amp by Jim Marshall allowing channel one to be significantly brighter and cut through the mix - a small change to a classic design with really big results. Increased filtering added a more immediate player response and a stiffer feeling from the power section. This circuit went on to define 70's rock and created the sonic landscape most people/players associate with Park/Marshall Amps. The P50M amp circuit defined a whole generation of music and was the bridge between the Park 45 and the Park PMV (Cascading channels and a Master Volume).