The all-valve JCM800 is one of the most highly respected 100-watt Marshall heads in the company's long history. Evolving from the legendary 100 Watt Plexi head, it was also their first amplifier to feature a Master Volume control. The very essence of simplicity, the JCM800 is a 1-channel, all-valve amp with no reverb or built-in effects. Its foolproof interface, distinctive roar and larger-than-life edge immediately set the standard by which all other rock amps were judged and it remained the industry benchmark throughout the entire 16 years of its production life. Now it's back by popular demand and they've taken this opportunity to give it a Series Effects Loop that features a true Bypass switch that takes the loop completely out of the circuit, thus ensuring the original tone isn't compromised in any shape or form.