It works , i ve tried it with various amps. This works well with Mesa valve amp only. Simply, you need to buy mesa amp in order to get its sound.
It s preamp tube, quite round tones, bright more then I like, i got the feelingthe sound is flat across whole range of tonality & volume. Simply sounds the same, no matter when its loud, quiet, low, deep.
good as orinal part for replacement, Tung Sol has 20x bigger personality.;)