Want all the gain you can get? This is our High Gain Option Retube Kit for the Kustom Couple 72 and Hard Top 72 Amps. This kit contains two handpicked High Gain ECC83S's for V1 and V2, a standard ECC83S for V3 and a current balanced ECC83S for the phase inverter in V4. The default power tubes are a matched quad of the JJ 6L6GC’s but you can configure this kit to use the JJ 5881’s by clicking on the "Customize" button!