2. amps-preamps
  3. 1095267415

Convergent Audio JL2 Triod Amp MK II Upgrade

JL2 stereo amps manfactured in 2004 and later have incorprated a power supply upgrade similar to the CAT Ultimate preamp upgrade for the mark II stauts according to Ken stevens. The new upgrade on the JL2 has not offically be called the MK II becaucse Ken does not like to change names very often but the new amps being produced now are superior to the pre 2004 models that were manfactured by Convergent Audio. Ken indicated that with the upgraded JL2 the sound is purer and more transparent than the earlyer produced amp. The cost of the upgrade is $1000.

I found this out when I had to send my JL2 back to the factory to replace some resistors that went bad. In the process of fixing the amp he offered me the upgrade which I accepted because it was already there. This is the first problem I have had with the JL2 in 2 1/2 years I have owned it. The fix also replaces the resitors and adds (4) more to make it far less likely to happen again something that is also incorprated on the new model of the JL2. Ken Stevens told me the JL2 does not use any fuses to protect the large transformer and instead uses (10) resistors for a purer and more vibrant sound compaired to fuses which are more commonly used on tube amps such as the Jasis Defy 7.

I will post my impression of the upgrade once I recieve it back and get some time to listen to the difference.

John
42659
catamps2c36
5 posts
 
Most manufacturers make no effort to protect their output transformers, but our transformers are considerable more expensive due to both size and exotic low loss core material and so we REALLY don't want to have to replace one. As a former equipment modifier, in my tweak years, I can attest that most old amplifiers have compromised output transformers due to sudden tube death. (A Dynaco ST70 with two good transformers is a very rare thing!)

But, that being said, I must admit that our six pack of metal film resistors have been overly protective (we could use one wirewound or power film instead but this hurts the sound and a fuse is even worse). We have upgraded this now to a ten pack of resistors and hopefully this solves the problem. If not we may consider just eliminating the protection altogether.

Ken Stevens
Convergent Audio Technology, Inc.
nkta
5 posts
 
My apology to Mr. Stevens. Although we both tried to get in touch with the other, unfortunately, I did not get his messages and neither did he mine. We have been playing phone tags for the past few weeks. So my previous comment is incorrect. Just want to rectify the record.
Regards, Nick.
catamps2c36
5 posts
 
Thanks Nick,

Ken
pubul57
3,712 posts
 
Just a short comment on CAT customer service. I own a CAT SL1 and JL2. Recently I dropped my pre "face first" while moving the equipment. All the switches were broken. I called Ken, sent him my pre, and in two or three days it was repaired on its way back home. Got the pre back, looks great, sounds great. In all it took 5-7 business days. The repair price was reasonable. I have no reason to doubt that Lamm offers great customer service (I also own a Lamm pre), and I would put CAT in that same category - at least that has been my experience.
More to discover