Thanks Neal! I am really happy with the Tung Sol driver tubes I am running now so I wanted to play with the preamp side of things. The Telefunken cost a lot more than I promised myself I would spend on a single tube (cost more than both the Tung Sols combined), but right now I can say I understand what all the hype is about NOS tubes. Even with them barely broken in (paid for a 24 hr burn in) the soundstage got WAY bigger. Bottom end is noticeably more extended, top end is more extended, and vocals really seemed to wake up quite a bit. They offer high gain options with these tubes, but I decided to forgo that option to stave off the microphonics concern common in small plate preamp tubes. You really want your preamp quiet as possible because your drivers will boost any unfavorable noise, harmonics, and microphonics. Honestly though, the gain on this tube is considerably greater than my stock preamp tube. The amp is nearly twice as loud (audibly) as it was with the stocker in there. Initially: Now: