Want all the gain you can get from your Classic 30, Classic 50 or Delta Blues? This is our High Gain Option Retube Kit and it contains a matched quad of JJ EL84's for power along with two handpicked High Gain ECC83S's for V1-V2 and a graded high current ECC83S for V3. Just let us know in the comments section if you're looking for max headroom, moderate or an early breakup so we can select a proper grade for the power tubes.