Want all the gain you can get? This is our High Gain Option Retube Kit for the Gibson GA 30RVS Combo Amps. It contains four handpicked High Gain ECC83S's with two of them being current balanced for the phase inverters in V3 and V4. The default power tubes are two matched pairs of the JJ EL84's but you can configure this kit to use two matched pairs of the JJ EL844's for an earlier breakup or a pair of the EL84's and a pair of the EL844's by clicking on the "Customize" button!