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The Jadis JA200Mk2 review---or slam!

In the current issue of Stereophile, Jason Victor Serinus reviews the new Jadis JA200Mk2....or should I say SLAMS the amp!!

Since I am new to the Jadis family, I thought I would bring up a few interesting thoughts on this review. The first is that I am totally understanding why an amp that uses Ten(10) KT150’s per side would probably not be a great solution at all!!!! Why, well JVS brought up the reason...although he did minimize the impact; the amount of heat this beast gives off is crazy! Space heater in disguise. What’s odd is how JVS also points to his Pass amps as giving off a ton of heat. ?? Anyhow, we then learn that the review was conducted using JVS DAC as the source...and direct into the amps....who does this??? Why on earth would anyone use a DAC to drive a large tube mono block for a magazine review!! No preamp was used. All of the photos of the amp show it using the KT120 tubes...all. There is mention of what the amp was designed with...the KT150’s, but there is some questions to what tubes were actually in the amp under review. Then to go on, the amp was apparently strapped for the 1ohm load....????? JVS doesn’t check these things!...and then states that the amp is not really that great in the bass reproduction. Huh, why would he think that a tube amp that is strapped to the 1ohm setting would produce prodigious bass with his hard to drive Wilson Alexia’s!!! Can we say classical "mismatch" here.
JA’s follow up measurements, while interesting as usual, are IMO also a little odd, what is the base line that he is using to determine accuracy??? Another tube amp...a ss amp, a hybrid design of some sort...his ears, someone else’s ears???

While I purposely did not consider the new Jadis JA 200Mk2 amp for my system, due to the immense heat output...and probable impact on reliability due to this factor ( IME, electronics seem to have a much longer life if heat is not that much of a factor!!! ( Am i one of the few that perhaps understands this??) Plus, i don’t need any space heaters in S.Calif.) I would think that a follow-up review ( preferably by a more experienced reviewer) would be in order....one who can correctly match-up this amp to their ancillary gear.
Anyone else have an opinion of the Jadis JA200Mk2 review in the current issue of Stereophile?
128x128daveyf
trelja
3,223 posts
 
@kyomi_audio you make some excellent points, and I agree with you.  The JA 200 MK2 should have no issue whatsoever driving the Wilson Alexias.

The Alexia may prove a bit more demanding than the WATT/Puppy and its successor, Sasha.  But I've heard several instances of those loudspeakers driven to more than good effect by the JA 80
rcprince
3,070 posts
 

Well, I think we now know why the amps were strapped for one ohm.  I had heard an earlier version of the mbl 101s driven quite well by the original version of the JA500s years ago (6550 output tubes), but I still thought it would be hard to imagine them driven with anything less powerful in tubes, glad to hear I was wrong.  Would love to hear that combination, especially with the JP200 MC (had to sell mine when I downsized, I still miss it).

 

kyomi_audio's avatar
kyomi_audio
63 posts
 
rcprince, you are correct, I was experimenting with straps. However, I heard no audible difference between 4-8ohm and 1ohm settings - at least not a significant one. That is why I did not bother to change them  back to 4-8ohm setting before shipping the amps to JVS. I can reassure you, it would have no affect whatsoever on the outcome of the review. 

You are more than welcome to visit Chicago and hear the JA200/JP200/101Mkii combination. It is quite remarkable. 
daveyf's avatar
daveyf OP
2,871 posts
 
George, you should remember that ALL speakers react differently regarding the impedance interaction with the driving amp. Therefore, unless you had the exact same pair of speakers that JVS was using, your results with a different speaker are going to be wildly different.
While you may NOT have heard any significant difference with the speakers you were utilizing for this test, that cannot be said for what JVS heard with his set up!
I would highly recommend that one of the reps for Jadis ( or you?? ) request a follow up from Stereophile; this time allowing them to do the set up in regards to the strapping and other items. ( hopefully someone over there would have the experience required to mandate a preamp in the front end!! ---or perhaps the Jadis rep or you can!).
All IMHO.
georgehifi's avatar
georgehifi
10,312 posts
 
The Jadis JA200Mk2 review---or slam!

Who in their right mind gives a tube amp to a reviewer with speakers that have a .9ohm EPDR loading in the bass, this is an admin cockup.  
This is what I wrote in the comments at the bottom of the Stereophile review. 


"The reviewers Wilson Alexia are full range passive (no active bass) but that bass can go as low as .9ohm EPDR, I can't see any tube amp even this good one getting the very best out of the Alexia's bass, like a big current pumping solid state could do."

Then you can read between the lines of the reviewer.
"the bass was also quite good"
"the bass less full"
"the double basses that give extra urgency and dread to the symphony's opening were hardly audible through the JA200 Mk.IIs. While I can't confirm that this bass shyness was due to the Alexias' impedance dip down low"



Cheers George



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