The amp is a Jet City JCA50h with all original tubes. It was time to replace the power tubes so why not go the extra mile and replace most of the preamp tubes, since it has a noticeable hum on the overdrive channel. This Engl Select was chosen for V2 position and an Engl First Choice for V1. The hum is now much lower and the amp retains the same character with a bit more polished sound. Would buy again. Also, thank you for the immediate shipment.