CAT JL-2 amp upgrade

I have a CAT JL-2 power amp, version 1. I know there is an upgrade to version 2. Has anyone had it done? What did it cost? How long did it take? What were the results? Thanks for your input.
not worth it spend your money somewere else
Thank you for responding, Wadia 150. By your comment, I assume you had the upgrade done. May I ask how much it cost, how long it took, and the sonic differences you noted between the JL-2 version 1.0 and version 2.0? Did you keep your JL-2 after the upgrade or change amps? Thanks.
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.

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.
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
I know what you mean regarding the Manley vs. CAT products. Both operate from totally different design philosophies. For the past year and a half I have owned the Manley steelhead phono stage and it is rich, full bodied, has nice tone and is very enjoyable to listen to. The cat Ultimate preamp is faster and more detailed than my manley but lacks size, substance and body which is my I sold my cat preamp and bought a Jadis JPS 2 (the linstage version of the Jadis JP80). Ken Stevens will insist when you talk to him his design is superior to others but this is true with most manufactures and the reality is all designs are imperfect. When I go to live concerts I hear the excellent detail and great bottom end extension of the Cat. When listening to live music I also hear the rich full body sound of the Manley and Jadis products which add size, substance and rich tonality to the music, something sorely lacking the Cat preamp.

The Cat JL2 amp has the common Ken Stevens design signature that the preamp has and yes it is not as rich or full bodied as other amps but I will accept this one weakness for the many strengths this amplifier has. I prefer the Jadis line stage and Cat JL2 combo where Ken prefers the JL2 and Ultimate mix. Going from the JL2 Mk I to the JL2 MK II was a nice upgrade Ken did for me while my amp was in the shop for some repairs and for 1k the price was well worth it because of the reduction in noise and greater transparency. The Jl2 went from a numeric rating of 9.1 to 9.4, very noticeable and positive but not huge as the basic character is the same. When talking to Ken Stevens about the JL2 Signature $5,000 upgrade he said the improvement would be about the same as going from Mk I to Mk II, what I did in late 2004 with my JL2. The biggest improvement in the JL2 Signature over the standard JL 2 is the addition of black gate caps in the power supply. He told me the other circuit board design changes were very minor sonically and was done mainly to improve reliability. If I had to guess based my past experience the signature upgrade would take this already excellent amplifier to a 9.7 but at 5k the improvement becomes quite costly and there are a lot of other ways to spend 5k including buying more records, upgrading your preamp or upgrading a turntable all of which I suspect will provide more of bang for the buck improvement for the money. Yes black gate caps nice to have if you have the money to spend but not a necessity, the JL2 is already so good in many ways.

There are three things you can do yourself to really improve the performance of the Cat JL2 for very little money, about $200.

1) Remove and replace the cheap tin male IEC connector in the JL2 with a pure copper or bronze furutech IEC. This made a bigger improvement than I expected giving cleaner power to the power supply resulting in greater energy and more drive.

2) Remove and replace the two poor quality Cardas brass female rca’s on the side of the amp with Vampire pure copper rca’s. You will notice cleaner and clearer sound and improved bass that is fuller without the bloatness of brass.

3) Remove and replace the two brass cardas speaker binding posts with copper. Eichman cable pods or a good pure copper posting will yield positive results similar to the rca’s mentioned above.

If you want even more performance from your JL2 bypass the internal 20 amp fuse and fuse holder located next to the IEC and expect another 3-5% improvement in sound. All these just take a little time, very little money and a good soldering iron.


Thanks Johnny for the report here. Your evaluations of the CAT preamps and amps to the competition very much mirrors my reports elsewhere on A'gon. These amps are very special indeed.

Your suggested DIY updates sound interesting but I would be weary of bypassing the fuse. These amps pull a lot of current from the wall and any little problem I would prefer to have protected by a fuse. Perhaps a "safe and sane" compromise would be to replace the fuse with one of the "audiophile grade" fuses? If it fails, it ends up costing you $20 or $30 vs. a major amp disaster .... or your house burning down.

I talked to Ken Stevens before bypassing my fuse and fuse holder and since I already have a 20 amp circuit breaker at my main fuse box we both agreed it should be fine. The 20 amp fuse was designed in for warranty reasons but in the 8+ production years for the cat amps he is aware of no problems with any potential power surges or damage that resulted. Ken indicated in a previous conversation that the JL2 is "self contained" meaning all major parts and assemblies are enclosed in a seperate retangualr steel case. The input transformer, output transformer and all wiring is enclosed with thick gauge steel greatly reducing any risk. In the rare event a fire does occur in one of these steel enclosures, none has occured yet, the damage would be limited to that specific area.



Johnny, thanks for the info. Has anyone experimented with tube rolling the output tubes in their CAT amps? Ken told me I was asking for trouble and I would end up blowing up the amp. I ordered the SED Svetlana 6550C tubes today from Upscale Audio. Kevin from Upsacle gave me a similar warning as Ken's about fooling with 6550 variants (KT90's, KT88's etc.)in CAT amps. I have got to say as I am listening to the CAT JL2 right now that the improvement from changing the 12AX7's and 6922's has made the amp much more musical and when my Amperex 12AU7's arrrive it should add more musicality to the presentation. I am very happy with the sound right now. My JL2 sounds very quiet, I don't feel the need to do the upgrade to improve performance in that area. My previous plan was to find a preamp to replace the CAT Ultimate MK2 to increase the musicality of the presentation but I am rethinking that option now. I may turn my attention to the digital front end instead.

I had a JL-2 and decided to sell it and purchase a new JL-2 Mk2 Signature. I am very happy I did as the signature version is a definite improvement over the non-Signature version. I believe that more expensive caps (black caps) are used in the Signature version. What you get is lower noise floor, better imaging and dynamics. The improvement in the sound makes the $5000 upgrade worth while IMHO. I am very happy that I got the Signature version. I have had it for a few months now. Happy listening.
Posbwp555, what preamps have you auditioned to replace your CAT? Have you found something you like better? I have a JL2 and use to have a SL1, which I have replaced with a Placette Active. I'm wondering about other pre-amp matches that might work well.
Hello Suttlaw. I had a CAT JL-2 and concidered upgrading it to the MK2 but decided to sell it and purchase a new JL-2 Signature MK2. The cost of the upgrade of the Signature MK2 is $5000 and regular MK2 is $3000. The difference between these models is the expensive Gates black caps used in the Signature version. I love the sound of the Signature version. It has a quieter background, more resolution in the entire freequency range without loosing the richness of the sound of tubes. The base is also tighter. To me the Sig MK2 was worth the extra cost. I also have the CAT Ultimate MK2 preamp and they match very well. I changed the input tubes of the amp as well as all of the tubes in the preamp (phono + LS) to RAM Super Low Noise and I am very pleased with the resulting sound. The only issue that I have is the damping factor of the amp is not enough for use with Eidolons.

I haven't tried any other preamps in the system yet. I wanted to hear the Emotive Audio Epifania ($25G) but the dealer never followed thru on his promises to bring one for a brief audition. Other posters have found the Aesthetix Callisto to be an excellent match for the JL2/JL3
amps. Many posters have decided that the CAT amps need a harmonically rich tubed preamp to balance what they find a
dynamic and detailed presentation of the amps. I have found from EXTENSIVE tube rolling in both the CAT Ult MK2 and the JL2 amp that the combination of the two is excellent. I can easily push the sound from overly textured (soggy classic tube sound) to overly detailed (hard and etched) and all points between these extremes with tube selection. I have found tube combos that strike an ideal balance (great texture, depth and soundstage combined with loads of detail and huge dynamic swings presented in a gorgeously relaxed fashion). Both the CAT pre and amps are very transparent the sound presentation is determined thru tube selection. Bugman03, I don't understand why you think the JL2 has insufficient damping factor when used with the Eidolon. The bass I hear with the Osiris is very good. I ran a pair of the Levinson 436's before buying the CAT JL2 and the CAT beat the Levinson in all parameters but especially in bass control and extension. From my experience, the Avalons work better with tubed electronics. My old pair of Manley 350's
also easily outperformed the Levinsons. Before all the Spectral and Rowland users comment, I have heard the Avalons perform very well with those SS amps, just not quite as good as with tubes. Bart
Thanks for your response Posbwp555. I had been considering a Joule LA150 MKII for the reasons you suggested. In speaking with Bobby at Merlin (I own VSMs) he suggested that rather than go that route I might want to try (I ordered it) the Ars Sonum integrated amp which he feels is very, very close to the separates considered to mate well with Merling (e.g. CAT, Joule, Atmasphere, Berning). This is somewhat of a leap of faith, since the Ars is a 30 Watt integrated costing $3,500, versus what some would consider SOTA seaparates worth $20,000. It would be very interesting to see if a synergistcally optimzed integrated and speakers can compete with some of the better separates. Of course the CAT will sound great with many different speakers with different sensitivities and impedance curves - it is a more universally "great" amp - that is not a point of contention. But the Merlins don't require a lot of power and have a very benign, easy to drive impedance curve, and Bobby know his speakers inside out. It will be an interesting experiment. After the trial I will be selling the little integrated or the CAT JL2. All things being equal, I'd rather run a small, simple integrated that can do the job (at least with Merlin speakers)- but I won't sacrifice musical satisfaction.
I am now using a Manley Steelhead phono preamp as my preamp and running it directly to the JL2s. Much better than my CAT SL-1 III preamp.
Still using my JL-2 original version amp. Has anyone had the upgrades to this model? Are they worth the money? Has the reliability been improved? Mine blew something expensive awhile back. Thanks for any information.

Tube gone bad blow your resistors?
Had a "standard" JL-2 that I bought used and it worked well with one re-tubing for 3 years. It handily outclassed anything before it, tube or SS. Then a bad tube took out a resistor and damaged one of the boards. After some attempts at repair myself, took a deep breath and sent it back to CAT. After some discussion and another very deep breath, had it upgraded to MK2 signature. Just got it back and the improvements are NOT subtle. Was already the best amp ever in my system, and is now substantially better. The newer boards have the offending resistors spaced out and sized more appropriately so bad tubes in theory do less damage. Haven't had it back long enough to comment on reliability, but the sound is very greatly improved, and the earlier version was nothing to sneeze at.