Why do some people say my name with 'uon' lol, anywho coming from the top of my head, the MP-3 is that long tube amp with one side being the transformers and the otherside is a whole bunch of tubes on one side. I'm a little not surprised those GEC A2900 are much better than Psvanes, as I've heard some and seen people say that it is indeed a superbly sounding tube, having not tried the GEC's, how much better would you rate over the Psvanes?
I'll admit I haven't played with a lot of 12AT7 tubes but I've got a good little expensive collection on the 12AU7 and the only time I see the Psvanes lose is as someone quoted on another forum with their comparison, comparing it to a rare NOS level 1950's Telefunken diamond based tube. What would be your second best 12AT7 valve besides the GEC's? (They don't come cheap).
Hello DefQon (and please forgive my previous misspelling,)
The MP-3 is one of two Atma-Sphere preamps. ( http://www.atma-sphere.com/Products/#MP-3 ) What you described is one of their (very fine) OTL amplifiers. Rosgr63 (post #486 above) uses one as his/her avatar ;~) The MP-3 (with phonostage) uses 11 tubes. 7x 12AT7's in the phonostage, and 2x 12AU7 + 2x 6SN7 in the linestage. I'm actually using the Telefunken 12AU7 you mentioned in the linestage (and sometimes Raytheon's with windmill getters ;~) along with a pair of the also excellent RCA red base 6SN7's.) This is a GREAT preamp! I'm generally not a fan of tube preamps (don't like listening to tube hiss after it has been amplified and sent to my speakers ;~) But the MP-3 is VERY quiet, and owning one was the only way I could get my hands on a balanced tube phonostage.
Regarding the GEC 12AT7, a little history: All I can say is the GEC tube is waaay ahead of the rest of the pack; and I'd tried many of those others before discovering the GEC's (I'll give you my thoughts on those below.) As I explained in my previous post #469, it had to do with my preference for high transconductance KT88 power tubes. At the time, about 5 years ago, the three vintage NOS GEC KT88's (Gold Lion, Gold Monarch, and blue label GEC) were the only really high Gm (transconductance) KT88 tube you could buy, and they had a (very deserved) reputation for air, soundstage, and a kind of 'sparkle', that no other KT88 could match, either vintage or modern. Then came the EAT's which were the first (modern) tube to compete with the GEC's performance (at $1600/quad!) I never owned them, but had friends with NOS Gold Lions who said the EAT's were even better. (I did try a quad of used EAT's which were excellent, but not better ;~) By that time, I had run through a whole bunch of KT88's, and made an interesting discovery: The higher the transconductance, the better the sonics, with a definite break point (for KT88's anyway) at around 9000 Gm. So when the Shuguang Black Treasures came out (about 3 -4 years ago) claiming 12,000 Gm, I thought I'd give them a try. I wasn't disappointed. They matched the performance of my vintage Gold Lions in every way. And as I mentioned, I'm currently trying out a quad of the new Psvane black-bottle KT88's which I think are better built, though may not be any better in perfomance (which is not a criticism ;~) I have an excellent Chinese source for Shuggies and Psvanes, so it's not expensive for me to experiment.
Back to the 12AT7's. My first quad of A2900's cost me around $160. Not excessive for good NOS 9-pin signal tubes. I wish I could remember what first caused me to try the GEC tube (so far no luck ;~) At the time, I was trying out all kinds of 12AT7/6201 tubes in my brand new McIntosh MC275 Mk-IV amplifier. (I had pretty much settled on the 12AX7 and KT88 tubes) I suppose, the GEC's were just another one I decided to try, I really can't remember ;~( But the minute I put them in, there was a noticeable improvement in bass performance (both clarity and power) and I also noticed my amp was drawing a few more watts from the wall ;~) The A2900 is a very powerful tube on its own. Most 12AT7's measure around 3000 Gm (new) whereas A2900's can measure as high as 5000! I guess the word is out because you can't hardly find them anymore for under $250 a pair +/-- (although I just picked up another pair on eBay for $167, lucky me!) The other 12AT7's I previously enjoyed (and which I would still consider excellent in most applications) are/were:
- Sylvania TMBP 6201's
- RCA long blackplate 12AT7's very strong tubes, great for rock -- and therefore good for drivers too, like the GEC's (but not as refined)
- Siemens 6201's (especially if you like a lot of bass)
- Valvo blue-label gold-pin 6201's which I thought were the best 12AT7 (most refined)*, along with the GEC's (in all apps. except as drivers)
- Psvanes -- which as I said, I'm just now trying.**
* By 'refined', I mean nice flat frequency response from top to bottom, and not of any of that 'fuzzy' edge you get with a lot of common 12A*7 tubes.
** The Psvane 12AT7's (and I'm also trying out some of their 12AX7's) seem to be excellent tubes. They have 3-micas which is unusual for most 12A*7 tubes, and are performing well in my MP-3's phonostage. The GEC A2900's still outperform anything I've tried as driver tubes however.