What would you say is the better sounding SET amp?

I love my Korneff especially with the addition of the Mullard ECC32=CV181 input drivers.. This combo is really nice. Although.. my overhauled and hotroded GTA Mono's using KR300BXLS Tubes is just as good and then some. The Korneff 45 is incredibly detailed and intimate. The GTA's sound equally delicate, but they have slightly lower floor noise with unbelievable power reserves. eg trumpet blat - which seems to come from now where, and just about pins you to the back wall. Large orchestal passages are explosive and stagering HUGE. The Korneff dosn't have that kind of explosive power. I am using Khorns -biamped.. They can be a bit forward.. so The Korneff is a bit well - a bit softer, easier to listen to .. I enjoy both amps immensely. The Korneff 45 is my daily choice. For real authority I connect the GTA's. But hold on for a ride.

Different horses for different courses. Aside from the difference in power output, the tubes do differ in ways that make one or the other more ideal in a particular application. I generally find the 45 tube to have an ideal tonal balance and beautiful sound, without the 300B tendency to be overly lush and wooly sounding. The 2a3 is much leaner than the 45, but it sounds very fast and detailed and has a beautifully extended and airy top end.

In my system, both 45s and 2a3s work well. I am currently running 2a3s in parallel single-end configuration, but I also have a pushpull 45 amp that sounds nice.

I am very very happy with my 45 SET.
You need very efficient speakers with it.

To summarise, "it aint what you do but the way that you do it". I confess I have'nt heard a 45, but all the rest in various manifestations. To me, there is more difference between amps, than between valves. It is the skill of the designer and quality of parts used, rather than the valve, that counts. Particularly of course, the quality and size of output transformers. To me the classical, euphonic, tube magic comes from the 300B, that is the amp which will grab you at a show, but may not pass a prolonged critical listen. Me, I use the 845 in a Viva Solista, just made Class A in stereophile. I know, I can hear the chorus of "so what" over here in the UK

"the 300B tendency to be overly lush and wooly sounding"

I think this is typical 300B experience for a lot of people, including myself, but I now attribute that primarily to circuit desing and implemetation instead of the tube.

My first 300B amp experience was with a Cary 300SEI, the epitome of "lush". But, I quickly realized that it sounded slow and bloated with exaggerated midrange and a flabby low frequencies. Most amps I heard after that were variations on that theme to a lesser degree.

Then, I got Welborne Labs DRD 300B(now Terraplane) monoblocks. They have none of those negatives. I would describe the sound as crystal clear, almost pure, without any exaggeration. The midrange is beautifully balanced withing the rest of the musical spectrum. The amps also reach down deep to dig out bass clean bass lines. ANd the high end extension is fantastic.

So, I'd agree with others that there implentation is a much bigger factor than output tube.

Having said that, my current favorite is both the Art Audio PX-25 and DRD 300B in my system. I loved Welborne's 45 Terraplanes driving Cogent field coils at the VTV show.

I've never had a chance to hear 2A3's, 50's, 205's, or VT52's. They are all on my list.