Want the smoothest richest tone possible from your F50? This is our Gold Pin Option Retube Kit. It contains three Gold Pin ECC83S's for V1 thru V3 and a balanced Gold Pin ECC83S for the phase inverter in V4. The default power tubes are a matched pair of the JJ 6L6GC’s but you can configure this kit to use the JJ 5881’s by clicking on the "Customize" button! If your amp is the combo version and you choose to go with the 6L6GC's then please let us know in the comments section and we will ship your kit with the special Double Mica 6L6GC’s which will greatly reduce any tube rattle.