Is the sweet spot for your M12 just a little to loud for you? This is our Low Output Standard Retube Kit for the Dr. Z M12 Heads and Combo Amps. It contains a matched pair of JJ EL844's for power to drop the overall output a couple decibels, a JJ 5Y3S rectifier tube, along with a JJ EF806 for V1 and a current balanced JJ ECC83S for the phase inverter in V2.