The 78 Modded JMP Kemper Profile Pack captured the sound of a 1978 Marsh*** JMP 100x amp modified for more gain and a hotter bias. This pack contains all those 70's rock Marshall tones that defined the sound of 70's rock. If you are looking for cleans lock else where this amp is all shades of British light, medium and heavy breakup, all with a vintage sounding Marsh*** character.