Want a very smooth and rich tone with less grit? This is the Gold Pin Option Retube Kit for the Bogner Uberschall. 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 E34L's but you can configure this kit to use the JJ EL34II's, EL34’s, KT77’s or Big Bottle 6CA7’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.