Jadis JA-200 Mk. II Amplifiers

[Milimetr]

Judging from pictures Stereophile revived version on KT120 tubes not KT150 so hard to learn the full potential with KT150 tubes.

I have read this Stereophile review. I think that sound description is completely disaster.
In my opinion Wilson Audio is very missed choice for Jadis as well as Odin power cords. This guy has no idea how to get proper sound from this amp.
Also a good preamplifier is a must with Jadis amplifiers. If the amp was driven directly from the DAC regulated output it could not end with goos sound. I am curious that Jean Christophe was there and not corrected the setup any way.

Wilson Audio, DCS and Nordost cables are all from the other end of sonic spectrum - the other universe. Can't believe that their connected JA200 in the middle of these gear and expected a good sound.
Jadis amplifiers are hard to setup - for sure and need some knowledge how to get best sound from them.

 

[Milimetr]

Interesting on CJ gear, as I have never heard Jadis before...so be interesting to understand any comparison you might be able to make. Meanwhile, newer CJ gear uses Teflon a lot...and I think it seems to have done some very good things in the same way you describe Teflon and Jadis.

Any thoughts on what you hear with CJ and Jadis...and (if possible) any comparison?

Sorry, but C-J adventure was many, many years ago. This gear were too expensive for me these time but I liked the sound a lot.

 

[microstrip]

Judging from pictures Stereophile revived version on KT120 tubes not KT150 so hard to learn the full potential with KT150 tubes.

No, they tested a Jadis Ja200 with KT150's - it is clearly specified in the review. However IMHO it is by far one of the worst and most poorly conducted reviews I have ever read in Stereophile. As far as I read listening was carried without a preamplifier - the DAC was driving the amplifier directly. Since I owned Jadis the JPL and the JP80 I know the difference between using a Jadis with a Jadis or tube preamplifier.

They were using (and measured) the Jadis strapped for 1 ohm, using the Alexia. Although these Wilson speakers have low impedance, they are known to sound better with amplifiers strapped for 6 or 8 ohm, otherwise they sound bass shy, a complain of the reviewer ... It seemed there was an error of communication between distributor and the magazine, something unbelievable and unacceptable!

Surely the amplifiers were set by Jean Calmettes. But a review is supposed to be informative and describe situations of use to its readers - I can not imagine who is going to use the JA200's in the 1 ohm position!

I do not expect SS bass from tube amplifiers, but we can read in the review of the JA200 mk1, using Avalon speakers : "How deep, controlled, tight, and satisfying the bass." Read more at https://www.stereophile.com/content...ier-jonathan-scull-review#eJkL0citpoDOdOKc.99

BTW, the review confirms that changes from upgrade were power transformer (probably to accommodate the higher current filament needs of the KT150 - a few percent higher than that of the KT120) and probably different cathode resistors in the auto bias circuit. No change in the output transformer or circuit is referred, the description of the Mk1 circuit is copied word by word and certified as correct. In summary this makes an old JA200 mk1 at the give away prices we can now find them in Europe the bargain of the year! But IMHO we have to get also a Jadis preamplifier.

Let us hope there is a follow-up to this review. Yes, I know I do not take reviews too seriously, but this one had too many mistakes about an amplifier we are debating at WBF!

BTW, I have owned Alexia's and used them at 8 ohm, although I tried the 4 ohm tap.

 

[KeithR]

No, they tested a Jadis Ja200 with KT150's - it is clearly specified in the review. However IMHO it is by far one of the worst and most poorly conducted reviews I have ever read in Stereophile. As far as I read listening was carried without a preamplifier - the DAC was driving the amplifier directly. Since I owned Jadis the JPL and the JP80 I know the difference between using a Jadis with a Jadis or tube preamplifier.

They were using (and measured) the Jadis strapped for 1 ohm, using the Alexia. Although these Wilson speakers have low impedance, they are known to sound better with amplifiers strapped for 6 or 8 ohm, otherwise they sound bass shy, a complain of the reviewer ... It seemed there was an error of communication between distributor and the magazine, something unbelievable and unacceptable!

I agree 100%. I can't believe the reviewer didn't try multiple taps as well. I know JVS is just starting out as a full-time reviewer, but I hope JA reads this thread because I'm tempted to write a letter to the editor.

Micro- the KT150 is so much better than the older tubes, I think you are underestimating the MK2 significantly. It also has the best bass of any tube, which is the irony in this review.

 

[microstrip]

(...) Micro- the KT150 is so much better than the older tubes, I think you are underestimating the MK2 significantly. It also has the best bass of any tube, which is the irony in this review.

No, I am not underestimating it. I have now burned-in 16 KT150's in cj LP275's and they also sound terrific in these amplifiers - much improved bass! My supposition is that the great difference between old and improved Jadis's is due to the KT150 and the new coupling capacitors from the SCR factory. But I have yet to confirm (or deny...) it.

 

[DaveyF]

I agree 100%. I can't believe the reviewer didn't try multiple taps as well. I know JVS is just starting out as a full-time reviewer, but I hope JA reads this thread because I'm tempted to write a letter to the editor.

Micro- the KT150 is so much better than the older tubes, I think you are underestimating the MK2 significantly. It also has the best bass of any tube, which is the irony in this review.

As I said before, i have not yet read the review in Stereophile ( for some reason I don't have my copy yet??); but I would whole heartedly agree that to listen to the amps on the 1 ohm tap while utilizing Wilson Alexia's and direct from a DAC makes absolutely no sense at all!! ( Unless you are extremely inexperienced, like JVS). The KT150 tubes in my JA30Mk2 are a minor revelation....they are certainly NOT lacking in the bass dept and they are very capable in the very top frequencies.
Admittedly I am using a CAT preamp upstream, which I would have thought ( along with a Jadis preamp) is one of the only ways to listen to the new Jadis line of amps. One other point, of all of the KT120 based amps that I have heard, they all sounded better if KT150's could be rolled in.

 

[lesacre]

Gentlemen, just wanted to point out that the amps reviewed by JVS do have teflon coupling capacitors. In fact, all our demo units have them, including JA30mkii, i50, JP80MC and JP200MC. Although pricey, they do make a big difference, especially in power amplifiers.

Kyomi Audio

 

[DaveyF]

Gentlemen, just wanted to point out that the amps reviewed by JVS do have teflon coupling capacitors. In fact, all our demo units have them, including JA30mkii, i50, JP80MC and JP200MC. Although pricey, they do make a big difference, especially in power amplifiers.

Kyomi Audio

Interesting, you do know that Teflon caps take almost a lifetime to break in!! ( well it just seems like a lifetime, probably about 600 hours, depending on the size of the cap). Were the JA200Mk2's that you supplied to JVS fully broken in....IOW they had that kind of break-in prior to his receipt?

Personally, I am not a huge fan of the Teflon cap, besides the above issue, i always hear a slight rounding of the leading edge on numerous instruments. ( maybe the gear I have heard is not fully broken in yet....even though it has 1000's of hours on it...who knows, LOL!!!! )

 

[Milimetr]

In my opinion using Teflon linking capacitors in Jadis amplifiers helps the sound to be more in focus, transparent, dynamic snd immediate.

 

[DaveyF]

In my opinion using Teflon linking capacitors in Jadis amplifiers helps the sound to be more in focus, transparent, dynamic snd immediate.

I have not heard a Jadis amp with the Teflon caps, but all of the other gear I have heard with these caps, it was as I stated above...
Have you heard a new Mk2 with and without the Teflon caps??

 

[Milimetr]

No, I did not. Ordered Teflon caps based on direct comparision between JA80 side by side with and without Teflon caps.

In your JA30MKII there are only two caps to replace I suppouse so easy to try and check.

 

[microstrip]

Gentlemen, just wanted to point out that the amps reviewed by JVS do have teflon coupling capacitors. In fact, all our demo units have them, including JA30mkii, i50, JP80MC and JP200MC. Although pricey, they do make a big difference, especially in power amplifiers.

Kyomi Audio

Yes, the new Jadis version uses excellent sounding Teflon capacitors - and compared to what we are used in the ultra high-end they are not too expensive. They need a long burn-in time because of the high voltage - the Teflon foil must be thicker to avoid breakdown. I was told that they should be mandatory, as you suggest!

 

[analogsa]

Personally, I am not a huge fan of the Teflon cap,

Me neither. But don't forget Jadis always seem to achieve more than the sum of the parts and certainly more than the topology would lead you to expect.

 

[DaveyF]

Me neither. But don't forget Jadis always seem to achieve more than the sum of the parts and certainly more than the topology would lead you to expect.

True, but this is why I asked Millimetr if he had the opportunity to compare a Mk2 with and without the Teflon caps. Plus, the one inescapable fact that they take forever to break in, is to me still a major deterrent. I am seriously against leaving tube based gear ( particularly amps) running all day long.
( even more so, if they are not being supervised while running!)

 

[lesacre]

DaveyF, JA30 MKii and the i50 were upgraded with teflon caps later. There was no need to wait for 600 hours - the sound improved right away. That is why I ordered Ja200 MKii with those caps factory installed. Also, they are not your typical run of the mill caps. There were especially made in France for the 25th anniversary Jadis gear. They are better than all other teflon caps I have heard.

The break in affecting the review does not make much sense. JVS was blown away by those amps in our Axpona room driving Vivid G1 S2. And I am getting superb sound out of them with MBL 101E Mkii, GamuT RS7i and Vivid G1 S2 speakers. You are more than welcome to visit and hear it for yourself - the proof is in the pudding

 

[microstrip]

True, but this is why I asked Millimetr if he had the opportunity to compare a Mk2 with and without the Teflon caps. Plus, the one inescapable fact that they take forever to break in, is to me still a major deterrent. I am seriously against leaving tube based gear ( particularly amps) running all day long.
( even more so, if they are not being supervised while running!)

The only capacitors that need break in are the coupling capacitors - you can do it removing the output tubes at high volume level, otherwise you will be wasting a few hundred hours of tube life.

You can also try using a CD such as the Purist Audio Luminist Enhancer - it will reduce burn-in time significantly. I always have a $50 DVD player with a Toslink cable ready to play the Luminist in repeat mode - why spending time listening in suboptimal conditions?

 

[DaveyF]

The only capacitors that need break in are the coupling capacitors - you can do it removing the output tubes at high volume level, otherwise you will be wasting a few hundred hours of tube life.
?

Micro, would you like to explain this to me....are you suggesting that you remove the output tubes, while the amp is playing at high volumes???

 

[microstrip]

Micro, would you like to explain this to me....are you suggesting that you remove the output tubes, while the amp is playing at high volumes???

OK, I spell it - remove the tubes and play the CD at an high level in the volume control of the preamplifier. The coupling capacitors will get the signal in full and burn-in, as their load are the the output tube grid resistors , still present in the circuit, and your tubes, speakers and ears will be safe meanwhile.

The idea of capacitor burn-in is exciting them with electrical signals, not heating them!

 

[analogsa]

Excellent idea. I guess the main filter caps have a sufficient voltage rating and the amp is safe to power with no output tubes.

 

[analogsa]

They are better than all other teflon caps I have heard.

Solen better than V-caps?