Cat JL2 with blown board. Advice needed

This is an older non signature model. A tube went out and the resistors protecting the output transformers combusted taking out one of the boards.

Now the good news: an upgrade to a signature model won't cost anymore with the damage. The bad news: this is my only stereo. Ken Stevens himself advised that it's really not the intent of the amp to use it for amplifying football and CNN. His point is that he doesn't do that and he can get tubes a lot cheaper than I can.

I really liked the amp even in it's non signature form. I have a symphonic line tube pre amp and Eggleston Andra speakers. I have been told that the Symphonic Line Kraft 250 is even better than the JL2 however no one has told me definitively against the JL2 signature.

Given the speakers and how I am going to use the amp, do I get it fixed and keep it or move on?

What would the amp be worth as is? You can buy the amp, pay $5000 to upgrade it and have a factory certified JL2 signature. It should have value.

Or is the signature even better than the Kraft 250 or any other SS amp in the $8k used range? If the signature is the cat's meow in it's range I am leaning towards keeping it and dealing with buying a lot of tubes frequently. I probably use the amp 750 hours a year.
The CAT JL2 Signature is likely the best push-pull, transformer coupled amp in the world. The Symphonic Line is proabably the amp that Ken Stevens would recommend if you did not buy his amp. So you basically have to excellent choices. I always prefer tube amps to SS amps, no matter how good the SS amp is; but that is my taste. I'm not sure you can get a defintive answer to your question. The ergonomics with excellent sound, and matching your preamp, go for the Symphonic Line. But for me the CAT is the choice for ultimate sound quality, but it is a lot of tubes, heat, and as you already know, a blown tube can do some real damage to the amp - no fuse protection as far as I know; that may be good for best sound, but you do have to own them over time.
I have had a pair of JL-3 Mk II sig's for 3 years, and I have just blown my second resistor in 2 months. That said, I have in the past gone over a year without blowing one. The resistors are fairly straightforward to fix with a solder gun (and a good light and a pair of loupes, unless your eyes are better than mine), and I've sort of resolved that there is perhaps a human price to be paid for the sound quality these amps are capable of providing, beyond their purchase price. Be prepared to also replace a trace on the circuit board with a short piece of resistor wire, if you had a really bad blowout. Whether it is worth all this is an individual decision. If you sell it and miss it, you can always buy another. As for me, I'm replacing the resistor and keeping mine, at least for now.
The CAT is great, but the problems you describe and I experienced are easy to fix if you know what you are doing, but I would not have a clue, and those that by the amp need to know this can be an issue for those of us with two thumbs. But, like you say, undoubtedly one of the finest amps on the market.
I would recommend one tip to all CAT owners when replacing resistors which I have found very useful. You cannot lay the amp directly on its back end on the floor because of concerns about damaging the on/off switch and fuse holder. I have found a beanbag chair to make an excellent stand, however, because you can rotate the amp backwards about 45° on the chair on the back end and top of the transformers, affording excellent access to the bottom without worrying about hurting anything sticking out the back.
I have spoke with you about this problem in the past.
I sold my CAT JL2 and use a SL Kraft 250. What I never realized before hearing the SL was how sloppy the bass from the CAT is! You never know what you are missing until you hear it! That is only one point, the truth is, the SL beats the CAT in ALL parameters. Better transparency, detail, articulation and extension on both ends of the spectrum. You already have the SL pre (the same one I am using). The SL Kraft is not your typical SS sound. It is the best SS I have heard and doesn't have the sonic drawbacks typically associated with SS sound. The SL pre is the right one for the SL amp (tried the CAT Ult MK2 on it). All this in a RELIABLE no nonsense product. An easy conclusion from someone that has used both. By the way, I have used all tubed systems for most of my life. The SL is the only SS I could live with long term (with the possible exception of Spectral) and I have no desire to return to tubed amps and likely never will.

Ken did tell me that if I did not buy his amp, he would suggest Symphonic Line. I've never heard an SS amp I preferred to tubes (the best I have owned personally was the Pass XA30.5), but I suspect this is just a matter of taste of what tubes do and what SS does and the reality being they can never really sound like each other. We all look for different things that satisfy us, so I don't think there can be any defintive claims for which is better for all listeners. If you can't be happy with the sound of either, you are unlikely to ever be satisfied. If I could find an SS that I preferred to my tube amps (Atma-Sphere, Music Reference RM-9SE, or my Ars-Sonum integrate) I would defintiely prefer the convenience of SS.
Do be careful before you universally recommend the Kraft 250 over the CAT JL2.
The Kraft 250 works for YOUR particular system - the CAT JL2 was always a misfit for your system because of the flagship Avalon speaker that you have. The CAT JL2 being a tubed power amp never had the ability from the get-go to ever drive your speakers. Thus, with the Kraft 250, you are hearing, maybe for the 1st time ever, what your speakers are capable of. You can thank Jay for this turn-around in your system.

I do not know much about the Andra speakers but it is entirely possible that they are beasts to drive (just like the Avalon flagship speakers) in which case the CAT JL2 is the wrong amp for the job. Yes, it'll give you good sound but I do not think that it would do justice to the Andra speakers - I could be wrong but this seems to be my opinion from what I have read & heard about these speakers. You would need a much higher wattage amp - if you want to stay in the tube domain then a VTL MB450, MB185 or VTL MB750 or a TRL 400, Wolcott Presence 220. If you want to switch to a s.s. amp then the Kraft 250 would do very nicely. Like Bart wrote, it is unlike any other s.s. amp you might have heard. Best of both tube & s.s. worlds + stable to 0.5 Ohms.

I suppose in some system that doesn't play below 100hz (I am thinking an actively biamped system where the CAT handles above 100hz) the CAT would be very nice. Even in a speaker that is relatively easy to drive, the CAT (with a damping factor of 10!) will not reproduce the lower octaves as the SL will. I sold my CAT to a guy that had exactly this setup (CAT driving 100hz and up). I am guessing he is enjoying it. I still would bet that even in that application, the SL would perform better (to most peoples taste)than the CAT. With the current crop of PLC and cables it is easy to push the SL waaaay over the neutral line to euphonic. As previously stated, I have loved and used tubes all my life and like you Bombay have a large collection of the best NOS tubes available. I rolled them all in the CAT JL2/Cat Ult MK2 combo. I disagree with you about a higher wattage tubed amp working well on his Andras. I almost went for a pair of VTL Wotan's
before Jay persuaded me to reconsider. The Andras and Avalons are looking for current not wattage. The VTL's would do the bass a bit better than the CAT (damping factor of 20 vs 10) but nothing like the SL (damping factor > 800!). I didn't realize things weren't wonderful until Jay graciously lugged his Kraft over for me. You never know something is wrong until something right points it out. I was lucky to run into Jay (he called asking about the ability of the CAT JL2 to drive his B&W 802's). I have thanked him for all the help he has given me over the last year or so. He is a great friend and very knowledgeable. I advised Defender1844 to repair or have the CAT repaired and sell it. The SL is perfect for his application. He also wants to use the amp to listen to his TV. His situation requires an amp that is RELIABLE.

Guys allot of good info. in this thread, when I spoke with Ken he also mentioned the same and had allot of respect for the Kraft line and said to me that if I was not going to use CAT product then it would be his choice. When I was speaking with him I actually owned Andra 2's paired up with Pass X600.5 monos. I was making some changes and actually bought MBL 101E's to replace my Avalon Isis speakers in my designated room but the Isis were not sold when my MBL's arrived and did not want to disturb the set-up. I decided to swap out the Andra's from my other set-up and break-in the MBL's, long story short the MBL's stayed in that spot. I wanted a amp to match up with them, hence purchasing a pair of JL3 Sig. MK2 mono's, during our conversations Ken did not speak highly of Pass, if you know Ken then you know how long I listened.

Reading the above info. now, if I would have only known all this back then that I would have to be a soldering pro etc. I would never have purchased them. Moving these arround so no to damage them or your self do to the weight and size for me is just too much. I had other issues too which meant they needed to go back to Ken and in the end I just got frustrated and decided to sell them.

I have never heard Kraft, when I look at pics and the little bit of info. regarding them I'll admit I'm a bit confused with; the finish and actual product line it's self.

First off the finish, I see on the site a pretty industrial pro looking finish, then I see some pics of a chrome look (which I like) and then a mat aluminum look. What is the finish.

Secondly, it's a solid state design correct, class "A"

Do the amps run warm, hot .....

The pre-amp is tube, solid state .....

Connections are they XLR or RCA and preference what is it.

My speakers are MBL 101E's, what would you recommend to be the ultimate fit, I need mono's due to my configuration and the space is fairly large. Prior to getting the CAT which is now sold and I'm looking for the right amp to end my amp quest I find my set-ups to be a tube pre-amp and solid state mono blocks.

Right now I'm learning more about Karan product and specifically the 1200's and look foward to hearing in my set-up in the near future.
Well, I wanted to give Defender1844 a choice between tubes & s.s. I remain confident that the choices that I gave him for large wattage tube power amps will do the job. My confidence stems from the fact that I know of several fellow Apogee speaker owners who drive their speakers with tube power amps to very good effect. As you might know, Apogee speakers are very tough/demanding low-impedance loads but the 4 Ohm version speakers in the Apogee portfolio respond well to large wattage tube power amps.
Further, if you search A'gon you will see that Albert Porter is driving his Dali Megaline speakers with 2 pairs of VTL Ref 750 mono blocks to very good effect. The Dali Megalines are a hybrid ribbon-cone driver speaker that have every indication of being a tough load.
I believe that Defender1844's Andras would be served well by large wattage tube power amps.
Now, none of these large wattage tube power amps are cheap! That's for sure. Jay's advice to you was very good from the financial view-point - rather than spend a lot for the VTL mono that you were considering, he suggested that you buy a fine s.s. amp that could do the job for much less money. I believe that the VTL mono would have been very good as well; it's just that you would have been out of a lot more money!
In the end it depends on Defender1844's tastes - if he likes tubes & wants to stick to them, there are some large wattage tube amps out there that'll suffice. Looks like Defender1844 is a man of some means & these tube power amps could be within his reach.
If he would like to switch to s.s. both you & I have given him a very good choice.
I think that there are other very good ( & expensive) s.s. choices as well - Gryphon, Karan, FM Acoustics & Goldmund.
So, depends on his sonic preferences & how much he's willing to spend.

>> As previously stated, I have loved and used tubes all
>> my life and like you Bombay have a large collection of
>> the best NOS tubes available.
tube rolling with NOS tubes inside Ken's preamp is one mistake that I made - it never sounded as good with NOS tubes as it did with his factory-provided tubes. The NOS tubes, no matter how fine, were always to noisy, too fat in the bass, too rolled off in the treble, etc & I felt ruined the sound. It could be one reason why your Ultimate Mk2 never sounded as good as it should have?
I've been using Symphonic Line power amps since 2001 with my Signature Mk3 preamp. The bass has never been uncontrolled. I have never felt like complaining about the overall sonics.


The SL doesn't run hot (not in my application or Jay's). It currently is offered in matte aluminum and black (chrome aranya is discontinued). The pre
is offered in aranya only. They make a tubed and SS pre.
As expected the tubed pre does some things better than the SS and vice versa. The pre uses 6922's in the signal path and EZ80/6V4 in the PS (yes, tube selection in the PS has a big influence on the sound). The stock 6922's are Sovtek.
Surprisingly they don't sound bad in this pre. They have been dreadful in every other component I have heard them (including the CAT pre's and amps). They are quiet, cheap and reliable and that is why so many manufacturers use them. Somehow Rolf from SL has found a way to make them sound decent in his pre. I am not going to rehash a discussion with Bombay on the merits of tube rolling in the CAT pre and amp. I'll just say that if you are using the stock tubes in them, you aren't even close to realizing their potential. Most that have rolled in them agree with that statement. John Fox uses JL3's and runs the tubes I sent him to audition (after trying countless combos of very expensive NOS). The only things our systems had in common were CAT amps (and some cabling) yet the same tubes produced the best sound in both our systems.
I know you refuse to buy ultra expensive tubes but sometimes they are the best (there is a reason people spend that much for them). Again, I don't post much on these forums anymore because I don't have time to waste arguing. No matter how many times some reviewer says that XYZ tube amp "plumbs the depths of what is possible in bass reproduction" or similar nonsense, their BS will not rewrite the laws of physics. I suspect that your friends with Apogees, Dali's _____ fill in the blank difficult to drive speaker, will be as surprised as I was when they directly compare their tube amps to SL in their systems.
Everything is relative. They may currently think their tube amp is doing the bass just fine until direct comparison. The VTL's have double the damping factor (sorry numbers sometimes tell valuable stories) of the CAT
and especially in tetrode do the bass better than CAT. Again it is CURRENT that controls bass not WATTS. There is a reason that most tube amp manufacturers will not tell you what their amps damping factor is. I called and spoke with Luke Manley's wife when I was considering the Wotan's.
She refused to tell the damping factor which I later found online. If you do a Google search on damping factor you will find a wealth of information that explains it in understandable scientific terms. It the the bass that costs all the money to get right. Some people are fine without it and love their SET powered ultra sensitive speaker systems. But if the objective is full range done right, damping factor and physics can not be anecdotally explained away. The problem with having heard bass reproduced correctly is the realization that nothing else (the rest of the spectrum) is right without it. FWIW IMHO

No one is trying to argue with you! Your inputs are well taken.
What I'm trying to convey here to Defender1844 (& anybody else reading this thread) is that they are NOT limited to only s.s. power amps for their application. Basically what you are saying is that the s.s. Kraft 250 is it & nothing else would work for Defender1844! I'm saying that Defender1844 has tube & s.s. power amp choices.
Hey, I'm a S-L user for longer than most people on this forum so I should be the one recommending nothing but S-L amps. That would be very limiting - very capable tube power choices exist as well.

Agree that tube rolling is very subjective - some like it a lot, other like it some & some do not like it at all. I just happen to fall in the 1st 2 categories.
With the CAT pre I happen to fall in the 2nd category - I liked it but with some qualifications.
With my Jolida 502A & Cary Sixpac tube amps, I out-right loved tube-rolling.
I've found tube rolling to be very gear dependent.
You feedback on tube rolling is well-taken.

>> Again it is CURRENT that controls bass not WATTS
You are right in a round-about way. Tt's impedance that control bass. Hig(er) current is a sign of a very robust power supply, which in turn can happen usually when the output impedance is very low.

we are mostly saying the same thing the only difference is that you are limiting him to s.s. power amps & I am saying that he has both tube & s.s. power amp choices.
Anyway, I do not want to argue with you - I agree it's pointless.
The info is there in this thread - let Defender1844 read it & do whtever he want with it. Peace!
I emailed Ken Stevens, made him aware of this thread and asked if he’d like to offer any advice. As he’s not a registered member, I volunteered to post his response and recommendations.

Hi, Defender 1844. I think we talked about this over a year ago. I really advise people not to use ANY tube amplifier in A/V systems or for background music. As I mentioned last year, I use a cheap Denon receiver for my A/V and physically switch speaker wires to the CAT amps when getting serious about audio. That's also why our SL1 A/V bypass engages when the preamplifier is turned OFF - it's literally a passive pass-through at that point.

I recall that you were quite insistent about using the CAT JL2 in your A/V system. I believe I recommended biasing the tubes a bit low to begin with (and then never adjusting bias thereafter of course) Did you follow this recommendation? I'm not being critical of you, just wanted to know if you did this.(This is not a proven recommendation - just an idea I had that might help. We really don't get many people using the amps in A/V systems.) Obviously if you did as I suggested then I won't suggest that other people try it.

An upgrade is certainly not needed to get this amplifier up and running again. We would be glad the send your dealer replacement fuse resistors. For the past three months, we've been using new ones which are more predictable and less likely to flame up, however we won't really know if they solve any problems until one of them blows! As yet, they have not. BTW, the purpose of the fuse resistor is to prevent damage to the ultra-expensive output transformer should a tube short internally.

Finally, regarding the comment someone made about damping factor as an indicator of bass quality: I find that DF is no more a predictor of bass quality than THD is a predictor of transparency. The JL2 has bass which is handily superior to ALL other tube amplifiers and almost all SS amplifiers despite a modest damping factor. On the other hand, anyone who has listened to a Crown IC 150 (DF of 20,000) will tell you that high DF could well be accompanied by really mediocre bass. I'm not saying that high DF is a bad thing, in fact "all other things being equal" it’s probably a good thing. But all other things are never equal, and there are many things far more important than DF (or any other spec).

The JL3 monoblocks do have a higher DF than the JL2 and they do have better bass. In fact the JL3 probably has the best bass of any amplifier in the world, including even the Kraft 400 (the much better sounding big brother of the Kraft 250). Clearly, much more than the higher DF is responsible for the superior bass of the JL3.

BTW it is the Kraft 400 which I have recommended to some people who are insistent on SS power, NOT the Kraft 250. In fact recently I heard from George that the 250 sounds much more like the cheaper RG series than it sounds like the Kraft 400. He said it was decidedly lightweight and over-controlled, lacking the richness of the 400. (The 400 could also be described as somewhat lightweight, but much less so than the RG series or, according to George, the 250)

Ken Stevens
Convergent Audio Technology, Inc.

good response from Ken himself. I tend to agree w/ him about DF being an indicator of bass response given that there is much interaction of the amp w/ the speaker to make just DF be the sole parameter.

Very interesting comments on the Symphonic Line Kraft 250 power amp! I DO NOT take any offence to them - just want to let all know for ample clarification.
At present I am using Ken's SL1 Signature preamp with my Kraft 300 (not 250) & I can confidently say that the combination does not lack bass. In fact I am very happy w/ the combination & The only change I'd make is to shell out some money to buy one of Ken's newer preamps like the Renaissance or the Legend. I believe the newer preamps throw an even wider, deeper & more life-like soundstage. If I only had some money......

I do not know which preamp George is using in his setup? I don't know why he is hearing a light-weight bass?
From Ken Stevens:

I said the Kraft 250 was described by George as being lightweight and overcontrolled. This is completely different from saying it "lacks bass".

Ken Stevens
Convergent Audio Technology, Inc.

>> I said the Kraft 250 was described by George as being
>> lightweight and overcontrolled. This is completely
>> different from saying it "lacks bass".

OK, thanx for the clarification & letting us know where Ken was coming from.
I interpret "overcontrolled" to mean more negative feedback?
"lightweight" to mean lacking midrange warmth?

Wish that George V would read this thread & post some info on what he was hearing w.r.t. the Kraft 250.......
Those of you that are prone to buying bridges from con artists, read the following:

Thanks for the response to everyone. Ken, yes you and I did talk. The damage was to an entire board which fried so it was beyond a simple resistor swap.

I have one stereo system which is connected to my TV. I'm struggling with fixing my JL2 and keeping it long term when Ken Stevens himself is telling me it's a bad idea to use a JL2 as the amp for my TV.

I have a McCormack DNA-1 temporarily which isn't horrible. Maybe the thing to do is fix the CAT, realize it's going to break and keep the McCormack around as a backup. Or fix the Cat, sell it and the McCormack and pull some more cash and get a killer SS amp.

I would be OK with buying 16 6550 tubes every 12 to 18 months if that was the only maintenance a JL2 required. I'd even upgrade to the signature as I thought the regular JL2 when it worked was incredible.

I don't think I'll send it in and get the one fried board replaced and not get the signature upgrade though.

Has anyone been able to keep a signature up and running 3 years without down time using it 2000 hours a year? Replacing tubes is not down time. Am I just not being realistic here?
wanted to update this. Upgraded to a JL-2 signature. Buying tubes all the time will suck but the amp is just too good to let go.