Djh - I recently went through a similar search. I have a very fine Simaudio I-5 integrated but after I got some Devore Fidelity Gibbon 8 speakers I was curious what they would sound like with tubes.
The Devore 8's are two-ways with the same sensitivity as your Sttafs and almost the same physical dimensions. My list of candidates for tube amplification was almost the same as yours but when I came across an interesting deal on an AES Cary AE-25 Superamp with a box of extra tubes I bought it. I then added an AES AE-3 DJH preamp and the combination with the Devores is absolutely wonderful.
I'd been extremely happy with the I-5 but the tube amp and preamp combination, which together cost about the same as the I-5, is simply more enjoyable to listen to. The AE-25 amp is auto-biasing and can take EL-34, KT-66, KT-88, 5881 or KT-90 output tubes. It came with two quads of KT-88's and one of KT-66's and I bought a quad of EL-34's to try.
The tube swapping has been fascinating, each type has a quite different sound and, because of the auto-biasing, comparing them is as simple as shutting down the amp, waiting just long enough to keep your fingers from getting burned during the swap and powering up again.
I hadn't owned a tube amp in forty years, since I built a Dynaco kit when I was 19, and had convinced myself that tubes weren't worth the extra effort but I was wrong. There is slightly more effort but not much, mostly in being disciplined about proper turn-on and turn-off sequence and shutting down the power amp when I'm not going to be listening for awhile.
The 15 triode watts of the AES Superamp are more than enough power for the Devores in my 11x17 listening space.
The Devore 8's are two-ways with the same sensitivity as your Sttafs and almost the same physical dimensions. My list of candidates for tube amplification was almost the same as yours but when I came across an interesting deal on an AES Cary AE-25 Superamp with a box of extra tubes I bought it. I then added an AES AE-3 DJH preamp and the combination with the Devores is absolutely wonderful.
I'd been extremely happy with the I-5 but the tube amp and preamp combination, which together cost about the same as the I-5, is simply more enjoyable to listen to. The AE-25 amp is auto-biasing and can take EL-34, KT-66, KT-88, 5881 or KT-90 output tubes. It came with two quads of KT-88's and one of KT-66's and I bought a quad of EL-34's to try.
The tube swapping has been fascinating, each type has a quite different sound and, because of the auto-biasing, comparing them is as simple as shutting down the amp, waiting just long enough to keep your fingers from getting burned during the swap and powering up again.
I hadn't owned a tube amp in forty years, since I built a Dynaco kit when I was 19, and had convinced myself that tubes weren't worth the extra effort but I was wrong. There is slightly more effort but not much, mostly in being disciplined about proper turn-on and turn-off sequence and shutting down the power amp when I'm not going to be listening for awhile.
The 15 triode watts of the AES Superamp are more than enough power for the Devores in my 11x17 listening space.