Besides their superb musical & sonic qualities, one of the great sources of joy for owners of vacuum tube amplifiers like the Leben CS600 / CS600X integrated amplifiers are adventures in trying different vacuum tubes to voice their amplifiers to best match their overall system characteristics, room, and their personal preferences.  I've been a huge... Read More »

In my "Sexy Blue Tubes: The Sophia Electric EL34-ST and Aqua 274B Vacuum Tubes!" feature review article for Positive Feedback (HERE), I provided a brief history of the EL34 and 274B vacuum tube designs, and then described the various technical performance enhancements that Richard and Sue of Sophia Electric implemented in their flagship Sophia Electric EL34-ST... Read More »