Want all the gain you can get from your second channel and the earlier breakup of the JJ EL844's? This is our Low Output High Gain Option Retube Kit for the VOX AC30HH Heads and AC30H2 Combo Amps. It contains a matched quad of JJ EL844's for power to drop the overall output a couple decibels, a JJ GZ34 rectifier tube, an EF806 for V1 along with three handpicked High Gain ECC83S's one being current balanced for the phase inverter in V4.