Want a really smooth and rich tone with less grit? This is the Gold pin Option Retube Kit for the Egnater Armageddon. The preamp section uses six Gold Pin ECC83S's with one balanced for the phase inverter in V6. The default power tubes are a matched quad of the JJ Electronic 6L6GC's but you can configure this kit to use the JJ E34L's, EL34II's, EL34’s, KT77’s, Big Bottle 6CA7’s, JJ 6V6S's, 5881's, 6550's, KT66's or KT88's by clicking on the "Customize" button!
These are adjustable bias amps and all you need to check and adjust the bias is a Multimeter to use with the test points. Here is a chart from Egnater on the bias setting. Note: KT88's bias the same as 6550's.