This is the Standard "Integrated Quad" Retube Kit for the Mesa Dual Rectifier. The preamp section uses five ECC83S's with one balanced for the phase inverter in V5. The default power tube selection is an Integrated Quad with a matched pair of JJ 6L6GC's and a matched pair of the JJ KT66's. With the Customize option you can configure this kit to use a range of integrated quads including our classic KT66/KT88 and KT77/6V6 options. You can add rectifier tubes if you use them by clicking the "Customize" button. You can run either the 5U4GB's or the GZ34's. If your amp is the combo version then please let us know in the comments section and we will ship your kit with the special Double Mica 6L6GC’s (if selected) which will greatly reduce any tube rattle.
These amps are fixed bias with no adjustment other than the switch to go between EL34 mode and 6L6 mode. 6L6GC's, KT66's and KT88's are run in the 6L6 mode.EL34's, 6V6S's, E34L's, KT77's and 6CA7's are run in the EL34 mode.