I'm late to the party, here, but I'm very interested in the Spirit III and other Ayon amps. I think it's important to note that a big feature of the III is that it comes with Shuguang Black Treasure KT88s. I'm led to believe by a few references that the Black Treasures are a big step up. On the importer website, grantfidelity.com, Grade A Black Treasure KT88s are listed at $480 per quad set! I believe there are other upgrades in the Spirit III, as well. If in doubt, call the U.S. distributor, ayonaudiousa.com !! Nothing like first-hand information. The III also can use KT120s...don't know anything about them. I presently use an Art Audio Diavolo SET with 842VHD output tubes, a superb amp.