I may have a “sort of” answer next week. Last Thursday I spent the entire day ear testing a 2000S, a Morgan 200MP, a Reeves Custom 225, and an early 70’s SVT (actually a V9) with various tubes; JJ KT88’s, JJ 6550’s, Winged C 6550’s, and re-issue Gold Lion KT88’s. The main object of this test was to see what was best “sounding” at full on power tube saturation, not really relevant in and of itself to this discussion; I generally play clean with a little growl, while the other guy plays full on nasty, pretty much always.
Anyway, I’ve been running Gold Lions in the Reeves for about a year now, instead of the JJ KT88’s that are OEM for the amp, that I ran in it for about a year also.
We ran out of time and didn’t get to do a lot of testing with the 2000S, but I left it with my partner to play with at his leisure. I assume he will be swapping and re-biasing over the next week, and probably recording clips as well, so I may have some examples to share between Gold Lions and JJ’s in a Sunn circuit, albeit not a Model T.
I’ve never run JJ’s or Gold Lions in a Sunn, I currently have GT KT88’s, GT 6550’s, and original Genelex KT88’s in my Sunns, but only the Groove Tube KT88’s and 6550’s in my four output tube amps so I can’t make a direct comparison from personal experience.
I can share this though; as far as in the Reeves, the JJ’s did a great job. The Gold Lions might be a
little more dynamic, tighter lows and more “singing” highs. Power wise they may also have an edge, but not a real noticeable one.
However, the Gold Lions are more expensive, AND one of them red plated after a few hours of hard use, an issue I’ve never had with the JJ’s. To be fair, once I replaced the toasted tube, the Gold Lions have held up very well.
As Biltmore posts, JJ’s seem to be the “go to” tube here, and for good reason IMO. The are a very consistent, and won’t break the bank tube, sound very good. If and when I actually release my amp “project”, I will be equipping the production models with JJ’s.
As far as your posted usage requirements; “I will be playing with the amp all the way up and for several hours at a time”, I suspect that the sonic advantages that I illustrated for the Gold Lions would even out. As I said, I get a pretty “hi-fi” tone mostly. I like a lot of headroom, keep the stage volume to where the nuances of touch and the instrument come through. I let the PA do the “heavy lifting” in big venues.
Just my personal opinion; If you are going to be
banging on it, and going for big SPL’s mostly, I don’t think the extra cheese for the Genelex would pay off.
As I said, if my buddy does some testing with the 2000S over the next week or so it will answer your questions better, he flat
wails on his amps; the attached clip is the Morgan MP200 with Winged C 6550, into a pair of TL606 cabs loaded with Eminence 3015’s. NO effects, bass into amp into cabs, wide freekin’ open, that’s how he rolls…
