i use telefunkens on 12AX7 & amprex on 6922 ,i like this sound more than the stock tubes..(pulls you into the music more)
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I have tried Telefunken 6DJ8, Telefunken 6922, Telefunken cca, Telefunken 7308, Sovtek 6922, Amperex 6922, Siemens 6922, Telefunken 12AX7, EI 12AX7 and Tungsram 12AX7. I would rate the Telefunken cca's highest of all the 6DJ8 tubes, but for those for whom that is too bright, I would use the Telefunken 6922's. I did not like the Telefunken 7308's at all (too bassy, rough and unrefined). The Siemens and Amperex were somewhere in between. IMO, the stock Sovtek's were clearly inferior. I liked the Telefunken 12AX7's the best, although the EI's were very good and I could easily live with them. I felt the Tungsrams were rolled off in the bass. Generally, I feel that Telefunken's in the CAT Ultimate give great bass extension, great dynamics and a smooth, neutral, liquid midrange.
I use the SIEMENS goldpins at this moment, very very good performance. and they keep up doing their job.
I have a good stock of EDISWAN 6922 on hand, very musical easy sounding, but exemplary failure when used in the CAT.
The Siemens goldpins ARE not much around anymore...
my CAT is an mk 3.
i must confess i think about moving to Atma-Sphere MP-1.
This is a real old thread but I thought that I'd revive it 'cuz I've been tube rolling some in my CAT SL1 Sig Mk3.
Audiogon member Jafox was mighty generous & sent me 3 pairs of 12AX7 tubes - Telefunken, Ei & Mullard.
Additionally, I bought a pair of Telefunken 6922 off Ebay recently.
I also bought a pair of Amperex 7308 USN-CEP, white label, Made in USA. These have 1964 production codes on them.
The Tele 6922 are in the line-stage in position V6 & V7 (in lieu of the factory supplied Sovtek 6922).
In my case, I have 12AX7EH in the phono & line-stages from the get-go of owning this preamp. I.E. I never had the factory supplied Ei 12AX7. So, I've never heard them before until Jafox sent me a pair.
I have listened to the Tele 12AX7 & the Ei 12AX7 (yet to plug in the Mullards) & here's what I found:-
My reference is the Sovtek 6922 with 12AX7EH (original combination) accuracy, a little lean, 12 oclock sound without a shadow. With my power amps that are on the tubey side & warm, this combination suits me quite a bit.
The Tele 6922 with 12AX7EH took off the edge in the hi freq extremes, made the mids less gainy, mid-bass in fuller now. The CAT pre sounds really very, very nice now!
The Amperex 7308 USN-CEP with 12AX7EH added some warmth & gave up some details. A little more musical than the immediately prev combination & a little less analytical. A fantastic break from the "usual" CAT sound. I like it!
The Tele 6922 with Tele 12AX7 added more sweetness to the mids & made the CAT more wet sounding. Is this overkill/too much of a good thing? I cant say for now. It was very intoxicating & I had a hard time switching the system off. It was past midnight & I simply had to!
The Tele 6922 with Ei12AX7 was modestly less noisy (lower amplitude shhhhhh from the tweeter) but these tubes have no more than 20 hours on them. They certainly sounded very dry. It made me prefer the Tele 6922 with 12AX7EH combination. I probably need to run in the Ei12AX7 a bit more to see what it might really sound.
So far, the Tele 6922 - Tele 12AX7 is my favourite combination. 2nd favourite is the Tele 6922 - 12AX7EH combination.
The Amperex 7308 - 12AX7EH is for days that my mood is seeking bloom from the CAT.
Like I said, I've yet to plug in the Mullard 12AX7. From what Jafox tells me, it might entirely change my conclusions!!
the CAT Sig Mk1 USED to be hard on tubes. Back then Ken Stevens used 12AU7 instead of the 6922.
Then came along the Sig Mk2 wherein the internal cktry was changed & the 12AU7 was thrown out & replaced with a 6922. Ever since that rev, the CAT uses 6922 tubes.
It NO LONGER is hard on tubes any more than any other tube pre out there.
For example, I've been using the 6922 & 12AX7EH tubes since Nov 2001! These were used tubes. Now I need to send the unit back to CAT for re-tubing.
I have no info on how long NOS tubes will last. However, I suspect that one will be able to get approx 2000 hrs from them IFFFFF the NOS tubes are bought from a reliable source that can guarantee them to some degree.
I think Vintage Tube Services' website says it very well "85%-95% of Life, 100% of performance....". Usually with NOS tubes one is never going to get 100% life (you could but you'd pay thru your nose for NIB NOS tubes!). So expect the number of hrs of usuage to be accordingly less.
FWIW. IMHO. YMMV.
true, C123666. however, even w/ NOS the skeptic in me does not expect 100% life owing to the fact that these tubes are 30-40 yrs old & the vacuum is probably compromised some. If i get full life from them, i'm very happy & it's like icing on the cake but I go in w/ the mind-set that i'm going to get less life from them.
Anyway, that's what I meant to indicate in my prev post.
no word yet on the Mullard. Listened to the Ei12AX7 last night again - gave it a 2nd chance, so to say. A little better. I think that I haven't heard what this tube is capable of until I think that it reaches 75 hrs. That's too many more hours more to go!
So, I'm going to try the Mullard either tonight or tomorrow night (depending on the domestic situation).
Heard the Mullard 12AX7 tube last night & wanted to share the experience:-
The Mullard was placed in position V8 & V9 (like the other 2 12AX7 tubes provided), which is the line-stage section for those familiar with this preamp.
* high freq extension is very good. Much like the Tele 12AX7. For the 1 1/2 hrs I listened last night with a limited set of CDs, I could not discern any glaring diff between the above 2 cited tubes.
* mid-range - glorious! I think that this is what Jafox had been "warning" me of. Esp. with vocals. The voices soar & there's a certain sweetness to the voice (bloom?). Slightly more than the Tele 12AX7. Listening to trios/bigband with vocals was a pleasure.
* mid-bass - weak in my system.
* bass - weak in my system.
These 2 ranges of the freq spectrum, the Mullard came up short vs. the Tele 12AX7, the 12AX7EH (that I've been using for 3+ years) & even the Ei12AX7. The Ei12AX7 lost big-time to the Mullard in the midrange but it did have very nice bass. I realize that the Ei12AX7 is not broken in.....
Anyway, the Mullard does have mid-bass & bass but it's light-weight in my system & the sound spectrum seemed tipped up. I know & I've heard that my system is capable of more. If I hadn't heard any other tube besides it, I would not have realized this. Unfortunately, I have!!
Since I like a balanced sound nearer to neutral than not, the Mullard would be a 2nd or 3rd choice, I'm afraid.
Anyway, that's the long & short of it. Sorry if I have stepped on your toes. FWIW. IMHO. YMMV.
Hey good report here. I think the results are another example as to the importance to try different tubes on our own components in our own system. And this is what makes it possible to tune a system to our own liking.
Last week, during a power cable audition with two local audiophiles, near the end of our listening session, we swapped the Tele 12ax7's in the Callisto to the Mullard. There was clearly more resolution on the top, not so much extension, but simply more presence of percussion brushes, with the Mullard than the Tele. I felt this was as big if not more significant than the huge cost increase of a few power cords we had swapped. I don't think any of us noticed a reduction in the mid bass or bass with the Mullard. So in the context of the Aesthetix Callisto, we all much prefered the Mullard but for now anyway, the Tele is the tube to beat in the Io. I hope to soon try Mullard vs. Tele in various positions in the Io as there are 12 12ax7 tubes in this beast and 6 more in the PS.
Bombay, when you get a chance please send back the Mullards as I want to loan this pair to one of the local guys. And then I am eager to play with the Io. You can play with the Tele and EI for as long as you like.
one more data point, guys & gals, if anyone is reading this out there:
i just tried the combination of an Amperex 7308,white label, USN-CEP, made in USA in position V6, V7 & a pair of Ei12AX7 in position V8, V9. Executive summary: simply excellent! :-)
this combination seemed to gel like a hand in a glove. At no time was I ever made to feel that the Ei12AX7 was not broken in. Somehow the house-sound of the Amperex (which I've noted to be on the slightly warm side) counter-balanced the accurate sounding Ei12AX7 for an overall superbly balanced sound.
I played a number of tracks from a number of CDs & I got it all, I felt: excellent hi freq extension & performance. i did *not* feel that it was rolled of at all *nor* did I feel that it was fatiguing. I got excellent mids - not the sweetness of the Tele 6922-Mullard 12AX7 nor that of the Tele 6922-Tele 12AX7 but pretty darned close to the Tele-Tele combination. I got excellent bass - plenty but *not* boomy. clear bass & several shades of it. Mid-bass made a strong recovery after what I heard in the Tele 6922-Mullard 12AX7 case. Overall, I was a very happy - the sound was just what the doctor ordered & it played to the CAT's strengths.
I never stated the music I've been playing in heavy rotation. So here it is if anyone cares:-
Diana Krall "Live in Paris"
Diana Krall "Steppin' Out"
Dee Dee Bridgewater "Dear Ella"
Bob James & Earl Klugh "Two of a Kind"
Duke Ellington & Ray Brown "This one's for Blanton"
Chet Baker "Chet" - JVC K2 recording
Art Pepper "Winter Moon" - JVC K2 recording
Robben Ford & the Blue Nile - I *think* that this album is self-titled
Albert King "I'll play the blues for you"
old tubes are old tubes and cannot compete with new tubes.use electoharmonix and your cat will come alive 6922 electo and 12ax7 use the gold elites made in yugoslovia.i dont understand people that use 40 year old tubes and say they sound better thats impossible those have had forty years to leak and get weak
Some thoughts on tube rolling in the CAT Ult MK2 and CAT JL2. I have settled for now on Amperex 6922's in the CAT Ult and JL2. The cathode follower (v10) is a pinched waist Amperex 6922 PQ. I am using Raytheon 12AX7's (black plate square getter 1950's) in the pre. These tubes are ultra detailed with lots of high end energy and a tight punchy bass. If you follow this tube downstream (JL2) with the same tube listener fatigue will set in. I have experimented with the Tung Sol 12AX7 grayplate square getter. This tube has a fat luscious midrange combined with a fat somewhat overblown bass and rolled on top. It is not a bad combo but the Tung Sol smears detail somewhat.
If you reverse these tubes positions (TS in pre and Raytheon in amp) the wealth of high end and midrange detail is lost. I used to use the megabuck Amperex 12AX7's
(D getter 1950's) in both positions and I thought they were very good. It was not until I replaced them with the American tubes that I realized they were smearing the deatil. I then replaced the 12AX7's in the amp with Mazda silverplates (made in France). This seems to be a nearly ideal balance. The Mazda is a very well balanced tube that works very well with the Raytheon. It doesn't have the big fat bass of the Tung Sol but the bass is tight and in balance with the rest of the spectrum. It also doesn't have that seductive midrange of the Tung Sol but it doesn't smear detail and again the mids are in balance with the rest of the spectrum. When one area of the spectrum stands out it detracts from the seamlessness of the presentation. You end up listening to the parts instead of the whole. So it turns out that Joe of Joe's Tube Lore fame was correct about the 12AX7 tubes he tried.
They do lack focus. His description of a lack of focus is, I think, what I am describing as smeared detail. He just didn't try some of the best American tubes and the Mazda. I am using the Amperex 7316's D getter 1950's in the 12AU7 position of the JL2. The 12AU7 is a very good tube family unlike the 12AX7's. There are many good options in the 12AAU7 family and I have tried some that are good but the 7316's always edge them out. Here I think Joe dropped the ball and described this as a mediocre
tube family. I would love to hear more people chime in on this thread, especially owners of both the CAT pre and JL2, JL3 amp. Bart