Convergent Audio Preamps

I need some help understanding the line up of CAT preamps. I see "SL-1", "MKI" , "MKII", "MK III" "signature" and "ultimate" all over the place. Are these all various historical iterations of a single preamp, or are are they different models offered at the same time?

How many current products in the line? Would someone mind tellign me the historical sequence... and if possible, how each subsequent iteration changed the overall character?

I can't tell you how each iteration changed the overall character 'cuz I have not heard many of them. However, I can say that the each iteration made the CAT SL1 pre sound even better & less noisy (from several conversations with Ken Stevens). I think that it would be correct to say that the overall character did not change; rather, retained the CAT "house sound" (if there is one! Again, several conversations with Ken Stevens).
The CAT SL1 was 1st offered in 1985. The name SL1 has always remained since that time with a post-fix letting us all know which iteration of the preamp was available for sale. At any given time only 1 (one) preamp was available for sale by CAT. However, ALL prev models that were in the market were serviced & maintained by CAT. The CAT SL1 Signature Mk I, Mk II & Mk III were offered in the early, mid & late 1990s. I know that the my SL1 Signature Mk1 was upgraded to Mk III by the factory sometime in 1995. The Mk III version was offered until 1999 at which time the Ultimate Mk 1 was introduced. In 2001 (I think) the Ultimate Mk 2 was introduced. The Ultimate Mk 2 is the latest & only version of the CAT SL1 preamp for sale now. Ken unveiled a $15,000 preamp called the "Legend". Production is to start on this this month, if I'm not mistaken.
Prior to the SL1 Signature Mk 1, the SL1 Reference was the model offered for sale. Before the Reference, I believe that it was called simply CAT SL1.
Hi,If you are looking for a used C.A.T pre-amp,start with the sig Mk 3 that was a big improvement over the Mk 2,then you have the Ultimate mk 1 and 2.The Legend will be released by june but the Ultimate will still remain in production because of the price difference.Hope this helps.

Hi all. I ordered a new SL1 ultimate, MK II which I expect in the next 2-3 weeks. I'm very excited as I hear the CAT+ Berning is a wonderful match. Anyway, I have a tube question:

Regarding the linestage, I understand there are 3 6922's and 2 12AX7's. I happen to own a matched PAIR of the very ecellent 1960 vinatge (US-made) Amperex "Pinched Waist" PQ 6922's which I used to wonderful effect in my former First Sound preamp. Naturally, Im thinking they would also sound fab in the CAT, but the CAT used three of these. So in what positions does it make most sense to try the PW's in?

I dont know much about what these tubes do to the signal individually, but I would think that 1 or 2 of them might be more sensitive, hence, I would try them in those positions. I know I could call Ken, but I am sure he would poo poo the whole thing, as i recall he's not for rolling tubes in his gear, but i want to try. You dont need a degree in operations research to figure out that there would be 3 possible ways to insert 2 tubes into three slots, and I guess i could just do it and listen, but i figured I would tap the collective AG community.

Thanks - Art
the input linestage tubes in position V6, V7 are more important than the V10 position of the 6922. So, try the pinched waist 6922 in those positions 1st.
thanks bombaywalla! That is exactly the info i was looking for. Just curious, ever roll the tubes in yours? Art
i rolled the tubes in my SL1 Sig into NOS GE smooth plates and Russian rockets in the Phono stage. Hugh difference!! Waaaay more dynamic and much quieter with greater air and extension.
Having heard the Ultimate but not the Ultimate 2, I personally do not feel there is large difference now.