If you want to be able to dial in that special Marshall amp sound without actually purchasing a Marshall amp, check out The Guv'nor overdrive pedal. This pedal was created in the late 80s to replicate the drive tones of the Marshall Plexi and JCM800 amps. The Guv'nor allows you to control the gain, level, EQ, and sports a loop output for use of other pedals. Famed guitarist Gary Moore used this pedal on his album "Still Got the Blues," speaking to the pedal's ability to build up anything from bluesy tones to stand-out leading tones.