Albert Porter is a true fount of information on tubimg Aesthetix products, so hopefully he will post here. In the meantime, you might check the archives for threads involving Albert and the Aesthetix IO, as I recall some very detailed information about that unit that might carry over to your line stage.
Albert is indeed the resident guru in the Callisto and Io but Jadem6 has probably done more tube rolling and tweaking to the Calypso than anyone else out there. A good place to start is JD's review
I am using a Calypso with JC1's also. I've rolled Brimar-England, Tungsrams and GE Longplate 12ax7's, all from Upscale Audio. Still running stock Electro-Harmonix 6922's, have not rolled those. I listen mostly to rock, blues and some jazz fusion and chose the GE's.
I auditioned all of these tubes at the same time, and the GE were the best for me and my system. A great rock 'n roll tube, IMO. All of the above tubes were very quiet.
The stock Tesla's were decent, but a little closed in & rolled off in both directions,
Please describe the characteristics of the GE tubes in comparrison to the others when in your system, and explain why you feel that the GE is "a great rock 'n roll tube."
I too have the Calypso and primarily listen to Rock & Jazz. When I do get around to rolling tubes, I do not want to lose the detail/resolution & punch that I get from the stock tubes. However, I would be looking for a warmer/richer sound.
I really believe that this is system dependant...synergy is key.
You mighy want to try 5751s (Sylvania Gold pins are the holy grail of 5751s but my GE 5 star's work beautifully) in place of the 12AX7s they have slightly lower gain but some how brought more air and soundstage to my system. Mullard 10Ms may indeed be the best tube but even if you can afford such an expensive preamp the price of these tubes is absurd and really verges on the ridiculous. The brightest sound may in fact be found in a very humble tube such as a current production JJ or Ei. If your Calypso is new it already has that. You might want to see if rolling the 6922s to a Siemans or Mullard 2493 not 2492 does the trick. In general the manufacturer uses a tube it can getrepeatedly and believe it or not even with expensive gear cheaply so I tend to ignore their voicing experiments, despite the fact that it is counterintuitive. I have seen far too many fine pieces of equipment use Sovteks which I have yet to hear even halfway decent in my view they are terrible tubes. I don't get it.
Barrelchief, in short, the Tungsrams just were not "right" in the bass department. The Brimars were sweet, but too laid back for rock. As kevin at Upscale Audio describes the the GE's as "light and bubbly, like a young blond." I agree with this assessment. More can be read on my tube roll in my thread on Calypso vs. Arc LS25...
Mechans, thanks for the tube info. And I agree, Sovteks suck.
I recently decided to buy a set of Platinum grade GT GT12AX7M from Upscale for the phono stage of my Janus. I've tried quite a number of NOS 12AX7s here, including Bugle Boys, Teles, Mullards, Mazdas and Ediswans. I can tell you without a shadow of a doubt that these tubes sound as good as any, and furthermore display the lowest noise levels of any of them (essential in the phono stage, not as critical in the line stage, which is inherently quiet). As good as these are, I see absolutely no reason to go hunting further.
At the same time, I bought a pair of what Kevin describes as 'Early Russian 6H23/6922 Type 3'. These are also excellent, but IMO do not affect the overall sound as much as the 12AX7s.
I ended up with Tungsrams in all positions. E88CC (6922) and 12ax7's. I have been more than pleased with the overall sound and the preamp is dead quiet. The E88CC's do need a long burn-in of about 300 hours. The 12ax7's require far less. Many of the NOS Tungsrams require pin cleaning, as they come pretty oxidized. In my system, this combination produces tight, accurate bass, smooth top end, and superb inner detail. During the E88's first 100 hours, the sound changed pretty dramatically and I almost gave up on them. Glad I didn't.
What pray tell is a GT never heard of it. Is it a type of 12AX7 as in a 12AX7WA or is it a brand?? If so where do they come from etc.
GT = Groove Tube, 12AX7 tube. Sold in many guitar shops, but used in audio as well. Supposed to sound like a Mullard if I'm correct. I have a couple lying around here that I wasn't too impressed with. Price is right though and you could do a lot worse for new production tubes. Golden Dragon sounded better to me. Of course IMO nothing beats NOS of which I have Mullard, Telefunken and RCAs that I rotate in my phono stage.
GT tube suck. I order a platinum grade GT 12AX7 from upscaleaudio, one of the two make noise the second day and Kevein won't even allow me to exchange it. I try many other 12AX7 from GE, telefunken, sovetk. all sound better than stock one and no noise.