Jadis JA-200 Mk. II Amplifiers

I had the Ja 100 and magma on the verity at the same time. Both are different, jadis do have a magic

I have the Jadis JA-80 and my friend has VTL MB-750. We don't have the same speakers, and I think that's what makes the biggest difference.
I think you should keep the MB-750. The Jadis are wonderful and I will keep mine forever for the wonderful dynamics they are capable of. The thing with Jadis is that they have extreme spec tolerances. You really have to match tubes every time. If not, caps and things start to melt in them.
A big advantage with the MB-750s is that they measure and calibrate each tube and you even get a warning to replace a tube if it's not proper.
With Jadis, a fuse blows the first time it happens. This fuse is connected to a faint red led light on the back. Unless you see that faint light when it happens, you wont see it again.
I really love the sonics of Jadis power amps, but the practical handling and care can be very annoying. If it wasn't for the sonics, I wouldn't keep them.

i love the jadis sound.
beautiful, full bodied, weighty rich sound.
the newer models offer a little more resolution with the use of more modern tubes.
i use the ja-30 with kt-88's and they are high current, class a, auto-biasing, olde-worldly-built beauties.
the 200's use a lot of tubes. can be a problem with that many tubes.
another option is the gryphon antileon evo. not tube, but nice sound.

The new Jadis mk2 amplifiers are *much* better than the older versions. They are far more transparent and not as golden sounding, but retain Jadis musicality. They are also considerably more reliable.

KeithR said:

They are also considerably more reliable.

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I would be extremely interested to get info about what Calmettes did to make them more reliable. Really honestly.

I used to own the Jadis DA88s , integrated amp using 4 KT88s per channel . It was a sonic marvel , not the most accurate but producing what I term as fantasy sound , sunshine filled . Reliabikity however was a problem . I have often flirted with getting back to Jadis on many an occasion and particularly the JA200 .As mentioned the mk2 models are much more stable . The DA88 mk2 has been very favorably reviewed by JH in TAS.

http://www.theabsolutesound.com/articles/jadis-da88s-mkii-integrated-amplifier/

Thanks.

Jazzhead said:

As mentioned the mk2 models are much more stable

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Is that what Jadis or the importers say or does anyone know what was done to achieve that?
I'm asking because I did quite a lot of research to improve reliability myself on my mk1.
I can't see any differences on the circuit or components other than the option to use KT150, which is also possible on the mk1.
I changed the configuration on the mains transformer myself to use KT120, and that was a really good thing in terms of reliability because the amp doesn't utilize the full tube power potential.
But still, the design seems very sensitive to tube tolerances.
You need to match not only plate current but also transconductance, which is not commonly done by tube suppliers.

The very early JA80s had three double triodes and some other variants existed. But I can't see any differences with mk1 and mk2. What are they?

a year ago I was hot on getting tube amplification and briefly looked closely at Jadis, likely the JA80 Mk2. I read an article (might have been attached to a review) that talked quite a bit about some significant changes Jadis had made to improve their quality control and performance. I just searched for that same article but could not find it. it might have been related to a visit to the Jadis factory and some details related to that.

maybe someone has a link?

Calle_jr said:

I have the Jadis JA-80 and my friend has VTL MB-750. We don't have the same speakers, and I think that's what makes the biggest difference.
I think you should keep the MB-750. The Jadis are wonderful and I will keep mine forever for the wonderful dynamics they are capable of. The thing with Jadis is that they have extreme spec tolerances. You really have to match tubes every time. If not, caps and things start to melt in them.
A big advantage with the MB-750s is that they measure and calibrate each tube and you even get a warning to replace a tube if it's not proper.
With Jadis, a fuse blows the first time it happens. This fuse is connected to a faint red led light on the back. Unless you see that faint light when it happens, you wont see it again.
I really love the sonics of Jadis power amps, but the practical handling and care can be very annoying. If it wasn't for the sonics, I wouldn't keep them.

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I think you are confusing the VTL MB-750 with the VTL Siegfried's. The MB750 have individual bias but we must check tube current individually with a meter. Although it does not need matched tubes I found that it sounded (and measured...) significantly better with well matched tubes.

Practical care of tube amplifiers can be very simple if we have an open mind and like modern measuring gadgets .Every tubophile should own a Bosch PTD-1 to measure his tubes from distance. Point it at the tube anode plates and you immediately know if a tube is defective in two seconds. I also use it to check bias in solid state amplifiers - you point it at the zone of power transistors and can get an idea of any bias unbalance.

Since long my preferred audiophile tools are from Bosch - a distance laser meter with an accuracy of 1.5mm and the contactless thermometer - also very useful to check for heat leaks in the house!

KeithR said:

The new Jadis mk2 amplifiers are *much* better than the older versions. They are far more transparent and not as golden sounding, but retain Jadis musicality. They are also considerably more reliable.

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+1

As some may know, I just acquired a Jadis JA 30Mk2. Why did I pick this model?...well with Jadis ( and frankly most other tube amp manufacturers) I happen to believe ( strongly) that the sweet spot of their line almost ALWAYS lies in their mid to lower powered amp. The benefits one gets ( if said amp can drive one's speakers) is IME as follows: 1) Less heat output ( less heat almost always means a longer component life), 2) Fewer tubes to acquire --leading to lower expense upon re-tube, 3) Lower probability of tube failure, due to fewer tubes, 4) Easier ability to match tubes, 5) Possibly fewer chassis and therefore fewer parts in the signal path, 6) better ability to transport ( yes, I know this is generally infrequent, but lugging four or more heavy chassis around is not my idea of fun), and lastly 7) An ease of maintenance if one ever needs that.
I have heard the new Jadis JA 200 Mk2, it is an excellent amp, and I would have put it high on my radar "IF" my speakers were fairly inefficient and my room was very large. Although personally, I probably would not own speakers in a large room that are inefficient...thereby doing away with the need for any high output amp. ( and almost always the consequent heat output that these amps typically give off!)
Why do I believe Jadis is far more reliable than in the past...because if we look at the failure aspects of the past, they are typically related to a few products....The Defy 7 range ( due to a poor internal design of the circuit board and parts construction related to how the part attached to said board ) and some of the higher powered models...the JA 200 and the JA 500 ( primarily due to the quality and type of the tube utilized in these models) ( I have no idea about the crazy JA 800--and couldn't care either, why would anybody want a monster heat engine like that???).
Today, Jadis has re-desigend their transformers, are using far superior quality tubes ( the KT120's and the KT 150's) and far superior quality parts in general.
Would I risk a high powered Jadis amp...aka the JA 200 Mk2 model or above....did I???
Not to say that these are bad amps or unreliable---and they will sound great, just not as great as the lower powered versions.
Here's a question, what is the acquisition order for gear, after the room is decided? Speakers first so that everything has to conform to their attributes, or the reverse, all up stream gear first and the speakers have to be synergistic with the upstream gear? Hmmm, perhaps a good topic for another thread..

DaveyF said:

(...) Today, Jadis has re-desigend their transformers, are using far superior quality tubes ( the KT120's and the KT 150's) and far superior quality parts in general. (...)

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Can you tell us more about this aspect? Some time ago I read in a french magazine that they were still using the same transformers as designed by the founders, JP Caffi and Andre Calmettes decades ago, but improving layout and parts of the classical models.

Some people associate the Jadis sound to the mechanical damping they used in their potted output transformers.

microstrip said:

Can you tell us more about this aspect? Some time ago I read in a french magazine that they were still using the same transformers as designed by the founders, JP Caffi and Andre Calmettes decades ago, but improving layout and parts of the classical models.

Some people associate the Jadis sound to the mechanical damping they used in their potted output transformers.

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This is from the Jadis site:

"The latest Jadis models feature improved power and third generation output transformers. The magnetic circuit, copper wire, insulation and manufacturing techniques of the transformers have been improved. The copper wire has been upgraded to a higher purity wire. A new resin coating treatment reduces the noise floor, while upgraded circuitry and improved filtering of high voltage result in more pure current."

Ron Resnick said:

Francisco, how would you compare the sound of the Jadis Class A push-pull amplifiers to VTLs?

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The class A's I owned were the JA80. They completely different from the MB750s - less defined bass , more detailed, more lively in the high middle frequencies and a great treble. Surely they did not have the power or the ability to move air of the VTL's - their bass and middle low was what people call "lazy". It ameliorates if we use a Jadis preamplifier. As far as I remember I did not like the Jadis JA80 power /ARC preamp pairing. Jadis are colorful amplifiers, but a lively coloration that is really enjoyable.

The class A/B Defy 7 is a completely different beast. More dynamics and slam, but more rough and less refined.

I must say I did not put the Jadis in service time enough to optimize or tweak them - probably I never used the best (more adequate) cables for them.

DaveyF said:

This is from the Jadis site:

"The latest Jadis models feature improved power and third generation output transformers. The magnetic circuit, copper wire, insulation and manufacturing techniques of the transformers have been improved. The copper wire has been upgraded to a higher purity wire. A new resin coating treatment reduces the noise floor, while upgraded circuitry and improved filtering of high voltage result in more pure current."

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Thanks. What are they calling "latest models"? I have emailed them in the past more than once (in french, bien sur) concerning mk2 and mk3 versions and always got the answer "some passives parts" and mechanical hardware changes (it seems to mean connectors) to please our international distributors.

Do you know if they already sell a point-to-point wired DA7?

Ron Resnick said:

That is very interesting, Francisco. Thank you.

Did you ever have occasion to compare directly the JA80 to any of the NAT amplifiers?

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No experience at all with NAT amplifiers.

Jadis has better tone, decay, and a general magic than VTL. Some might consider jadis more colored while I consider jadis more real. I will always have jadis in my consideration list but think there are alternatives to VTL unless you need that Siegfried kind of power using valve PP. VTL will have more bass and might be controlling tougher speakers better