CAT JL-2 amp upgrade

http://forum.audiogon.com/cgi-bin/fr_memb.pl?aamps&1089202007&memb&zzBugman03

I would hope that a JL-2 or JL-3 owner who had the upgrade done would chime in with some before and after comments. I have seriously thought of this with the JL-3 Sig's but they sound so mighty good already. But if the upgrade brings on more resolution and dynamics, woo hoo, that would be awesome. Just wish I could hear the two versions side by side. Would be a lot easier to quantify the differences to determine the value added right then vs. putting that same money elsewhere in the system. But CAT products do not see a version change too often so this change could truly be incredible.

In Late 2004 I had my early model JL2 updated to the Mk II status. The biggest improvement I heard was a great reduction of noise and a much more quieter backgroud. This very postive change was apparent from the first moment I played the first tune on my table. The reduced noise level results in better transparency and more inner detail being revealed. Was it worth it, Yes in my opinion.

Note: This is not the $5000 signature upgrade which is much more extensive and costly but the Mk II upgrade from there early version of the Mk I which I believe was about $1000 at the time. A nice improvement indeed.

Johnny

Hi, Johnny.
Do you remember how long it took CAT to return the amp? Do you know what they did internally to the amp for the standard upgrade, or do for the Signature? Did the changes to the amp reveal any changes necessary for the rest of your system, particularly cables or power cords? How many hours did you put on your original tubes before retubing? Do you get a warranty with the upgrade? Thanks for any further information.
Steve

I just purchased the CAT JL2 and am also trying to determine from people who have had the upgrade to Sig to describe the improvements and quantify the improvements (obvious improvement, subtle improvement, etc.). The person I purchased the amp from (a dealer) said that he has the new Sig but doesn't hear much improvement so far.
The Sig isn't really broken in yet but he will let me know when it is. My thoughts on the JL2 versus the Manley 350 monos I was using are as follows. The Manleys have a much fuller (sweeter, richer) sound across the spectrum (I prefer this), the JL2 sounds lean in comparison. Where the JL2 betters the Manley is in detail, transparency and coherence at high SPL's especially with large ensemble bands. I think where the JL2 gets this tendency toward detail and accuracy is from the output tubes (6550's). VTL used to use these in their old 300 monos and when they switched to KT90's the sound became decidedly more musical.
I did almost immediately get rid of the sovtek 6922 input tubes in favor of Amperex SQ 6922 made in Holland (nice improvement). I also replaced the stock EI 12ax7's with Amperex 12ax7 D getter long plates also a nice improvement.
I have some Amperex 12au7's d getter long plates in transit. For my taste the Manley was a better match in terms of musicality but the CAT does everything else better. So I guess I will start down the path you have travelled John. Finding a preamp (to replace the CAT Ult MK2) with full textural qualities to mate with the CAT's somewhat analytical presentation. Johnny, if you got the MK2 upgrade for 1000,
you did well. Ken told me he is charging 3000 for that upgrade and is urging people to do the Sig upgrade for another 2000 which is much more comprehensive