Want a little cleaner front end and the earlier breakup of the JJ EL844? This is our Low Output SRV Option Retube Kit for the VOX AC15C1 and C2. This kit uses a JJ 5751 for V1 which is in-between an ECC81 and an ECC83S in gain. We follow that up with a standard ECC83S for V2, a balanced ECC83S for the phase inverter in V3 and a matched pair of the JJ EL844's for the power section.