Very thorough review, John. Unfortunately, that's too many permutations for my itty bitty brain to follow, and im afraid i never woud have been able to sort through the differences if i were to try the same thing. Anyway, your dedication, thoroughness and vigilance will help future callisto rollers!
There is a very, very important variable i may have missed: WHAT VINTAGE were these 6922's (and other) tubes you were rolling? It's a well known fact that the best 6922/7308/ 6DJ8's were made in the 60's and early 70's - and that anything in the mid to late 70's and beyond are JUNK. There are a lot of tubes flying around out there claiming to be one thing, but are another (mostly 80's tubes being passed off as "genuine" well they are siemens, but the production info conveniently left out).
I myself was burned on a "Siemens 7308" I had procured ata hefty price, having been told, "this is THE ULTIMATE tube for your First Sound Preamp" only to find out with some research it was manufactured in 1980. It's not all about the date either - it sounded lifeless. Clean and transparent, but nothing special, sterile and boring. I sent it back.
IF yu dont have one already, you really need a good tube source, someone who will not deceive or rob you. In my last expereince (before I sold the First Sound), I landed some REL 1960 Amperex 6922 "Pinched Waist" tubes which, as Joe of Joe's tube lore documented were simply superb. The difference between it and te 1980 Siemens 7308 was enormous, beyong comparison really.
Anyway, I'l step off the soap box now - but remember tube-children, "it's a jungle out there, buyer beware"
Excellent info John! Now I am suddenly wondering if there is such thing as wire-rolling craze in pianos, like there is tube-rolling in audio gear.
Jafox, thanks for the excellent description of your tube experiements. Now that you've found the tube complement that gives you a sound you like, take it up another notch by applying Walker Audio Extreme SST to the tube pins (very lightly - follow the directions), let the SST break in, and listen again. It's amazing how many layers of veil there are in our systems that can be lifted.
really, that stuff works? for REAL? No kidding? Honestly? No joshing? You're not puling our legs? Not april fools day? you mean it? Not "opposite day"? Not pulling a fast one? Not prevaricating? Scout's honor? Cross your heart, hope to die? PINKY SWEAR?
Ha! Loved the post Artg!
Great info John, it sounds like you've had quite a few changes in two weeks. I will bring a couple other 12AX7's to try when we next get together.
Artg: Your concerns on "legitimate" tubes has much merit. It would be easy for many people here to misrepresent the vintage or manufacturer of a tube. But this is the case for all such audio purchases here.
I have had much success with 3 sellers of tubes here so I check out their inventory before I look elsewhere. As for the vintage of the ones I got this week, I will have to do some searches and see if I can learn an approximate date of manufacturer based on the labels painted on the tubes. If people are painting old labels on new tubes, surely there are many more prosperous counterfeit operations than profiting from the few of us tube users in the world.
As for the later tubes being "junk", other than the Amperex 7308 being too way much of a good thing (midrange presence) the remaining tubes far exceeded the stock Sovtek and ElectroHarmonix tubes. So even if we can not get our hands on those prized pre-1970 tubes, I am convinced there is much musicality to be gained by swapping out the Sovteks in some areas.
And yes I fully understand the overwhelming nature of trying so many tube permutations in these products. I seriously considered trying a pair of the Amperex 7308 and a pair of Siemens 6922 in the two groupings within the Callisto but I was very pleased with the Siemens quad.
Again, I relied on all the efforts previously made by Albert. All I did was learn for myself if these tubes were as dramatic as he claimed. He clearly did all the legwork with determining the good from the bad in the many many tubes that he surely tried in these units.
I never would have the patience to try 4 or 5 brands of each tube type. Keep in mind, I am more a "forest" rather than "trees" kind of audiophile so putting a lot of time and effort for that last pinch of refinement or perfection is not what I am after.
Like Albert's experiences greatly benefitted me, I was looking to share what I had learned in 3 nights what could very well take the efforts by someone else down to one night. And that was the purpose of the "what did I learn" summary.
So Art, don't let all the tube changes scare you. It really was rather straight forward. Now the Io is a different beast!
Guido: Funny man. Maybe Itzhak Perlman should consider string rolling as well? Cat lover here so no cat gut jokes please. Or is that just tennis racket strings?
Rushton: Where do I get this SST? I guess I can not put the cover back on the Callisto tonight afterall.
Jafox, here's the link to Walker Audio for Extreme SST:http://www.walkeraudio.com
Lloyd offers a money back guarantee if you're not satisfied and you return the unused portion in 30-days. I'm definitely a believer in the result with my Io Signature, plus every other contact in my system.
John - as always, your points are dead-on. I guess it's a matter of cost/perfromance ratios. The stock sovtek's cost X and delver a certain baseline perfromance. they's also very cheap because they're in abundant supply, so their ratio is decent. Later date (ie. mid 70-80's and beyond) NOS 6922/7308's may be better than stock, but at what price? If properly priced (there is a surprisingly large supply of what i lovingly refer to as NOSJ (new old stock junk)), then their ratio is also reasonable - maybe even a tad higher than the stocks. OTOH, if the NOSJ are being sold as "DA BOMB" at $250-$350 per matched set (which is what you might need to pay for the real deal early 60's stuff), then suddently the ratio SUCKS, dig? Reputable tube sellers will either only deal in the good stuff (e.g., Andy at www.vintagetubeservices.com) , or will properly discount the NOSJ for what it is.
Anyway, i have no reason at all to believe any of your tubes were NOSJ - I was just posessed again to share my painful experience paying premium $$$ for NOSJ (in my case the 1980 produced Siemens 7308).
As for the overall nature of your analysis - i really applaud it - it was excellent, and i could see how systematically, it would be doable rolling all those babies in there. I've done some rolling on my Berning, and on my previous First Sound Preamp. Im a big fan of fine tuning sound on tubes - Bravo!
OK, Rushton, I just bought some walker extreme SST.
John, believe it or not, string players tend to be also compulsive string rollers by nature. No danger to cats though, Pearlman likely uses some newest variant of steel strings. No NOS either, a string more than a couple of years old is not even good enough to be deemed NOSJ. . . it's pure Junk. And the US Marine Corp's band sadly lacking string instruments, there is regretably no such things as JAN strings either.
For your 12AX7's try a pair of RCA 5751's 3X mica Black plates. They have slightly less gain, but have excellent focus and resolution and are grainless in comparison to most all 12AX7's..they will make a audible difference...Ken
Hi Ken, I was thinking exactly of these tubes to try in my DAC as it takes a pair of 5751 and also a pair of 7044. I have so much harmonic richness from the DAC but would like a more low end extension and maybe even a little more top-end presence. So this is the next tube rolling project. But I will try these in the Callisto because of your recommendations.
Ok Art, I almost bought the SST today but now I'm not sure to buy the regular or the premium. I will wait on a report back from you here before I make the move.
John, I have some of the regular I can bring over and we can try it before you but.
John, the regular SST is good, but the Extreme SST is actually better. For me, in my system, it was worth moving to. It's certainly worth starting with J.D.'s offer to try his regular SST and then decide from there whether you want to pursue it. I'd suggest first starting with some interconnect or speaker cables: the effect will be consistent elsewhere. The Extreme just improves on that result. Here's a link to my comments about Extreme SST from a few months ago:http://forum.audiogon.com/cgi-bin/fr.pl?ymisc&1101694286