Apologies in advance, but I’m going to sound off regarding that index card-sized Vali 3 (again)…
Since I posted initial thoughts, I have rolled in GE JAN 5670s (all from the mid-1980s), a Sylvania JAN 5670 (1962) and a WE396A (date ???). I love all three tubes. The WE is the best all around, and it should be, given the prices being charged for them. It has an overall balance to it where everything jus sounds “right”. However, if it’s bass extension you’re looking for, my Sylvania leads the pack. It doesn’t do anything badly, or even just OK, but the bass is more present with that tube.
The GEs are very uniform, and tend to be pretty much a mini 396A. Not quite as phenomenal, just excellent in every aspect.
Forgot I also tried an JRC 5670 made by RCA (1962). This was somewhere between the GEs and the Sylvania. Better bass than the GEs, but not quite the Sylvanias level of oomph down low.
This amp is, in my opinion, far superior to the 2++, and every one of the tubes I’ve rolled has confirmed that. I will be rolling other compatible tubes in and out, because that’s what I like to do. Whether it’s the higher voltage rails that makes the tube produce more magic, or whatever else Jason did inside, I couldn’t say (nor does my nervosa extend to wanting to speculate on that). I’m seriously impressed.
Oh, and the darn thing looks really great too!