MGP guitar amp

MGP stands for “my guitar preamp”. The head started life as a Marshall MG100; all of its electronics were stripped out and it was rebuilt completely, in 2022, around circuits and PCBs of Jonny's own design. The new preamp has two channels on LND150 depletion-mode MOSFETs, the low-noise devices the Moon LaNDer proved, with JFET switching and buffering around them.

The preamp. Six LND150 MOSFETs make the gain, with J112 and J175 JFETs and TL07x op amps around them, and a footswitch selects between the two channels. Gain, Bite, Crunch and Boost shape the drive; Bass, Middle and Treble set the tone, with Contour, Presence and Resonance beside them; Volume and Master set the levels. An Accutronics BTDR-2V module adds the reverb, and an effects loop sits between the preamp and the power amplifier.

The board carries its own regulated supplies, from an LM317, an LM337 and a 7805, and a connection for a cooling fan.