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 AC15HW1. This kit uses a JJ 5751 for V1 which is in-between an ECC81 and an ECC83S in gain, a standard ECC83S for V2, a balanced ECC83S for V3, a JJ EZ81 Rectifier tube and a matched pair of the low output JJ EL844's for the power section.