Convergent Audio Technology SL1 Renaissance, Legend, & JL5 Black Path Editions*

I did but it’s not showing.

 

Are you sure Ken is using Black Gate capacitors? They have been discontinued for many years. Do you perhaps mean his proprietary Black Path caps?

 

Ken bought 3 1/2 skids of Black Gate caps 10 years back just for the Legends and he still has one skid left.

 

Very interesting! I don’t know what a skid is but I assume it’s a significant quantity. I thought I was being smart when I bought an extra dozen BG caps beyond what I was actually using in my equipment. Now I only have one left. I can understand why Ken would be saving his remaining BGs for his very best models.

 

Nice! That top cover must weight 10lbs.

 

The cover is very heavy. The bottom cover is also the same thickness but without the slots. These covers really improve the bass tremendously. Really surprising.

 

Now25, you might want to consider rolling in some NOS tubes. If you haven’t already done this, you will find that the stock tubes that Ken supplies...give a very...’stock’ sound. Big upswing in SQ with some good Telefunkens or Siemens, imho.

 

Haven't tried rolling tubes for CAT preamps all these years. Telefunkens would be good but not sure about the authenticity of the NOS tubes in the market. The EI 12AX7 is a replica of that tube I believe.

 

There are reliable tube resellers that have a store with stock that has proven authenticity. I would steer clear of eBay sellers if you are concerned about authenticity. I haven't had any problems with that, but when I have been a bit concerned, I have bought from The Tube Store (www.thetubestore.com - Your online source for audio vacuum tubes. ) or Tube Depot (Analog In ) or Parts Connexion (PCX INDEX ) or Tube World (Welcome to Tube World... Your One Stop Source for High Quality New Old Stock Vacuum Tubes ).

Those are all reliable sellers who have been around for years and I am sure that they would sell to you in Brunei.

Good luck. I have tube rolled with various tubes and had great success. My favourite is Telefunken by a considerable margin.

 

I believe Upscale Audio and Jim McShane are reputable online tube sellers as well. Don, have you ever tried Ei 12ax7 tubes?

 

I just had a pretty long conversation about these tubes with Ken last week. He went into a lot of detail about how the Ei's were manufactured using the same equipment as the Telefunkens and that a lot of care and detail went into the Ei12AX7's.

 

Thanks for the tips.

 

I actually bought a set of the tubes for the new Legend BPX from CAT at special prices and kept the eight month old tubes as spares.

 

Thanks very much for the recommendations.

 

Ei's are IMO not that great a tube. Unfortunately, some of the NOS tubes are quite pricey these days...but I think well worth it in the CAT.
I currently am using some NOS '63 GE 12AX7 long plates and some NOS 12AU7 Siemens. Both of these tubes were far more resolving and musical
than the stock Ei's.

 

Well...I got my JL5 Limited Edition back. Kudos to Ken and Lee for getting the rather extensive upgrade finished in a weeks time, two weeks including shipping time during the Holidays.
I had the amp completely re-tubed as the power tubes didn't test well. This is the problem with tubes, especially in power amps. They just are not 100% reliable. I have been using tubes for decades and I have tried NOS tubes including the $$$ Telefunken 12AX7's. I am leery about spending big money on NOS tubes that can go bad after a year or two and just keep getting more expensive.

The first thing I noticed is a lower noise floor which is always a good thing because that means even more nuances can be heard. The next obvious improvement was the sound stage was higher and wider. The other thing about the sound was that it was smoother and less fatiguing.

The JL5 Limited Edition works beautifully with my Yvettes and I think it is an amazing amp.

 

You have a great point about NOS tubes having potential longevity issues. Unfortunately, I think that is the price we have to pay to maximize the SQ of our tube gear...and CAT is no different. Listening to Ken’s gear with stock tubes is like putting hard and cheap tires on a Ferrari, the tires will definitely last longer and will cost a lot less in the long run, but the performance will suffer greatly.

 

No, I don't think so.
1. Have you heard his latest preamp renditions?
2. Ken has been designing his equipment around the tubes he uses.
3. Tubes that come from CAT are tested to the extreme, to the point that each tube has a specific placement. All tubes are carefully tested for sound.
I have used plenty of NOS tubes in CAT preamps and amps over the years and I do not think the tubes CAT provide are like cheap tires. I am not saying I wouldn't like the tubes you are using. I am saying your comment is hyperbole.

 

Nope. The tubes that Ken supplies in his gear is ok...but that's as far as it goes. If you want a very nice step up in SQ, then rolling in some NOS tubes is IMO the way to go. Yes, I have heard his latest gear..and in some ways it benefits even more with tube rolling. I get what you are saying about the cost and the potential for tube failure ( which is why i would only suggest acquiring NOS from a reputable seller), but unless you try this, you just won't know.
I have had this exact conversation with other CAT owners, all of them...with no exception, heard a BIG step up in SQ when they rolled in NOS...and got rid of Ken's stock stuff. If that's hyperbole, so be it.

 

Very glad you like the JL5 LE upgrade. I have never listened to the JL5 so I'm not sure what the difference would be. Totally agree with you on the black background due to the lower noise floor. I guess the Teflon circuit board would give you more transparency and micro details as the dielectric absorption is quite a bit lower than the polyimide board in the JL5. The JL5 LE drives my PMC fact.12's speakers with ease. Have you read the articles 'Why Circuit boards matter' and 'Why do Triodes sound so powerful' by CAT?

 

I haven't read those articles but Ken gave me a nice lecture. Let's not forget that Ken adjusted the tube bias as well, which is not part of the LE upgrade. The bias is now 16 mA as opposed to 25 mA. Ken says the 16 mA bias sounds better. So, with new tubes, new bias and the LE upgrade it's hard for me to know exactly what is doing what. The amp is definitely at a higher level overall.

 

Where are these other CAT owners? Again, Ken's stock stuff is thoroughly tested and measured for optimum performance in CAT equipment. Ken said some of the NOS tubes color the sound. Still, I get what you are saying, and I'd love to try some of those tubes. I just can't do it all. One thing at a time.

 

I’ll have to find out from CAT about the bias setting on my unit. If you would like a copy of the articles please PM me.