And after listening to the amp for many months on some reasonably high resolution speakers (4-way, dipolars)--I remain underwhelmed. Which makes me wonder if SS was always the more reasonable and ultimately preferable choice. Less fiddling, better overall sound (i.e., less trade-offs). I may relegate the Curcio to my university office--at least it'll bring up interesting conversations with the 18 to 23 demographic.
Bear in mind also that a Omegastar 260 has 4x the power. While it's true that in some regards tube amps generally seem more powerful than the really are, that's a lot different and the dynamics, range, and linearity seem significantly better than the U70. Getting two of them and running them bridged would likely be a very big improvement. And you'll save on the gas bill in the winter.
I would also note that although I haven't seen/heard the Curcio the U70 is A LOT better than a stock unit and noticabley better than any of the other mods I have heard. In particular the high end has tremendously better definition. The bass of the U70 is a significant improvement as well, but not as well damped as the mosfet amp. It was pretty enjoyable to put together and absurdly easy once I got the old parts cleaned up (and replaced the power transformer due to insulation problems with the original). If I ever do it again, I will almost certainly build it from new parts, which means a pretty healthy chunk of change by my standards (although nothing compared to the money a lot of guys waste in magic interconnects and speaker wires). I think it's clear that the performance, reliability, and value of the mosfet amps are a clear win i every category. But it wasn't for me and it's really just a disguised "repair" job. I REALLY fixed it!
Since we are on the topic, I also got the Super PAS preamp (with the same "repair" excuse for my father) and that is a whole different ball of wax. That's pretty fantastic and easily a match for just about anything going. As far as I can tell you give up *nothing* in terms of performance to *any* preamp I have tried. Assuming good tubes, which so far seems to be no problem. I wouldn't say it's better than the Omegastar, just slightly different, and (as mentioned in a 1986 Audio Basics) it does indeed work something like a CD "fixer" - just barely knocking the edges off of some harsh recordings. I probably am going to get a Super PAS for myself.
Brett
p.s. I haven't attempted any tube tests for the U70, so I may not be getting optimal peformance. I am using EH 6CA7, which are a lot better than the 40-ish year old 20,000 hour unknown brand EL34s, but I have no idea what I might be missing with other available tubes. I would presume that it could make a big difference- but it's awfully good as-is.
