JADIS JA80 with 6550 or KT 88 or KT90 ?

My Jadis JA80 was built in April 1999 and came equiped from the factory with eight 6550 valves.

Before deciding to buy a new set of tubes, I would like to know some opinions about the advantage or inconvenience of using the KT 88 or the KT 90 tubes in my JA80.

Is there any experience of using these tubes (KT 88 or KT 90) in an amplifier designed from the factory to work with 6550 tubes?

Many thanks for your cooperation.
I have had these Amp's before,Best of the Jadis line of amps. Musically speaking. (IMO) And have tried all of the configurations you are speaking of. In my personal taste, and or ears. The "6550's" tend to offer better bass, controll, and depth of field. But TOOB's are cheap enough to try all the above. Find the ones that's sound best to you and sell off the ones you don't enjoy as much. Forget all that "Golden Ears" crap! enjoy the ones that sound best to you..Hope this helps? For a great place to purchase? e-mail me. I can tell where to go, and offer you more advise, and save you $, and time.
Many Thanks for your advise Mang53.

After some more opinions I hope to receive, I will come back to you.


you may want to try some EL34s' as well. I use EL 34s' in my JA 30s' and Ja 200s'. I haven't tried any KT88 or 90s' but I really don't like the set of 6550s I have for the JA200s. The 6550s have a hard edge to them.
Good luck.
Definitely KT88s. 6550s: Edgy, dynamic, analyical. EL34s: Lush, loose, soft. The KT88 blends the best of the 6550 and EL34: liquid midrange with enough low-end punch to match the high-end air. In short the best balance. The KT90 does not work well in Jadis products except the JA-100 and Orchestra Reference which have proprietary output transformers specifically wound for the KT90. My reference JA-100s sound like the perfect transistor; very hard to beat. But for some reason I'm looking for a pair of JA-80s and some Gold Lions.
my jadis ja30 came with ei kt90 tubes and i haven't felt the need to change. i also haven't heard the ja30 with power tubes other than kt90, so i am kind of speaking blindly. i did change stock 12au7 and 12ax7 to nos tubes with great results.
good luck!
Thanks to all of you for your contribution.

This is to let you know that I have purchased the SVETLANA KT 88 and I that the sound of my Jadis JA80 improved a lot.
These valves are much better than the 6550 or the KT90.
Sound became much more airy and halographic; extremes much more natural , without loosing detailed.
I can assure that this was one of my best investments to improve my sound.

Regards specially to Khrys

The kt88 definatly my favorarate is the 6ca7 for musicalty and close second is the 88 none of the midrange glare the 6650 or KT90 has, the 88 is just more full bodied much more texture smoother highs and more natural, have had several pairs of JA80S also have JA200S JA500S JA50 AND 100s I like the 80s and 200s the best.
Interesting. Do you guys think if I switch the KT90's for 88's that my JOR will sound even better. The 88's have been recommended, but I didn't feel the need.
Also which 88's are good value. I don't want to spend say more than $200.
Baton Rouge
Of the 6550s I used in my old JA80s (from around 1993, had them over 10 years), the best of current production tubes were true Svetlanas (not Sovteks). They had some of the midrange of the better KT88s, though could not match them in that area, and had the best bass control of all the tube types I used in the 80s. They will give you most of what these amps can offer. The best 6550s ever in my amps were the Tung Sols, but you have to make sure you get the real ones, as there were a lot of phony ones out there in the market. And the best tubes I ever had in my JA 80s were NOS MO Valve KT88s (GEC Gold Lions, etc.). They are pricy, but lasted four times longer than any 6550 type tubes in those amps, had the midrange of EL34s (which sounded great in that area while they lasted) but much better bass, and seemed to be just the perfect tube for those amps. I did not like the KT90s in my amps--felt they were cold and lifeless, became stale-sounding after a while. Anyway, I see you got some Svetlanas, so you've gone the right direction, in my view.
Bartokfan: As Khrys pointed out above, the JOR's transformers are supposedly optimized for the KT90 tubes, though there still are many who prefer EL34s and KT88s in the amp. KT88s will likely give you a lusher midrange and a more "tubey" sound than the KT90s, which are leaner (Khrys's description as the perfect transistor is the way I felt about the KT90s too). As far as current production recommendations, I don't have any, but check the archives, there are a lot of recommendations on current production KT88s.

I have nearly new pair of JA30’s with KT90's factory fitted. Are any changes or re-calibrations required when changing between KT90’s, KT88’s or 6550’s. Or is it a straight swap?
Bump this one back to the top, looking for an answer to valve inter changeability.
from Jadis via email:
"JA30 is an autobias amplifier, it does not need any adjustment when you change tubes.
Kind regards,
JADIS Service Commercial / Sales Department
Chemin du Pech
Tel : + (33)
Fax : + (33)"
The KT88's just arrived, replaced the KT90's with the Elecrto KT88's and after only 10 minutes of listening, promptly placed them back in their boxes. I'd say the quality lost is near 50%. In fact had the original JOR came with these 88's I'd be one very un-happy camper.
Dumb me, doubting the french.
loss in all three fq's in the 88's.
hopefully my seller will take them back with some discount of course,.if not I;'ll put them up for sale here.
Paul, whenever you retube an amplifier, this happens.

Put the tubes back in, and let them run in for at least 25 hours. They'll open up. Trust me. It's called break in.

Now, I'm not the biggest fan of EH KT88 or 6550, and you may end up preferring the Ei KT90. But, whatever you use when you retube, even if they're Ei KT90, when you first power them up, they're going to be EXTREMELY constricted sounding, especially at the frequency extremes, and lacking in power big time.

Personally, I like the JJ tubes the best. But, interestingly enough, I have also arrived at the conclusion that the Chinese tubes being produced today are far better than anyone would expect. I would have never believed this if someone told me, but I've tried some small signal tubes recently that surpassed some extremely well regarded NOS varieties. But, even they needed a day or two to open up to the point where I was satisfied with them. For my money, I'm hoping I never have to buy another Russian tube.
The 90's sounded excellent in the first minute.
Sound EXACTLY the same as today.
What I want to know is, does the other Jadis amps that use the 88 have simulairty as the EH88? If so then I may want to ignore the Cayin A88 and other Jadis' that use the 88.
Seems that most all Jadis uses 88's now.
Can the DA30 accept KT90's?
Thinking about it now, I made the best decision in getting the 88's trying them in the JOR. The 88 is not the sound I'm looking for. Its too mellow and vague.
I love the details, sharpness projected by the 90's. No I think I'll hold off buying the Cayin A88.
I think my next amp will be the JA30. I was thinking cayin 500, but there again its a big fat tube and will not likely present the striking sharp image the 90's produce.
Yep I think the DA30 will serve just fine...headed over one more time to Jadis' home page take a look at her.
Just discovered why Jadis gives many photos of the same amp, shows each with different tubes. You get a choice of at laest 4 types of tubes. UNREAL!.
that seals the deal, I'm skipping the Cayin, going Jadis next amp.
Now has anyone compared the 30 vs the 60? also the DA50?
Anyone know some prices?
I have a DA30 and DA60. The DA60 is definitely worth the price of admission over a JOR, DA30, or DA50S.

The DA60 moves to some seriously larger transformers, which are the most important component of a tube amplifier. The trannies are what you should be paying for. On top of that, the DA60 is running twice as many tubes. Of course, it's painful when you retube, but the positives of all this are a surprisingly sweet, relaxed, and powerful sound at the volumes The Doctor (Mechans) and I listen - 95 dB at the listening chair. He says it's the only amp he's heard that produces such a natural and seductive sound, without going in to what he refers to as "tube blow" (when the lows get wooly). My Coincident Troubass subs run 10" Peerless woofers and require some current to do bass properly, no matter what a low power devotee claims. The DA60 is able to deliver the goods for these subs.

Still, again I'm going to say that when you put new tubes in an amp, they MUST run - in. I just don't believe the Ei KT90 sounded as good right out of the box as they do today because I have used these tubes, and still have a new quad I bought to replace in the JOR when I had it.

Your description of the EH KT88 being mellow and vague is what I also hear in that tube, as well as the EH6550. Believe me, a set of JJ E34L, KT77, or KT88 produce that lively, open sound, and is why I have all three. For what it's worth, I believe the JJ KT77 offers the best overall sound. The E34L having far and away the best mids, the KT88 having the bottom, and the KT77 having that powerful low end, with mids closer (though not quite close enough) to that of the E34L tubes.

You'll also realize significant improvement in a Jadis integrated by rolling the 12AX7 and 12AU7 tubes. I can't stress this enough.
Trelja, interesting comments. So there is a difference in the EH 88 tube I had and the stock 88's that Jadis puts in their units? I'm very happy with the 90. After hearing the EK 88 I'd be afraid to try any other tube except the 90.
I believe Jadis offers a variety of tubes for the DA30.
Also hows the DA30 compared to my JOR, a big step up? As the DA60 is out my price range. Though a used one might be a future possibility.
What does rolling the 12ax7 mean?
Paul, I think Jadis supplies KT88 tubes these days in the Orchestra and DA lines. Pierre Gabriel does take pictures with a lot of tubes, however. And, it shows the flexibility of the amplifiers.

I believe Jadis was using KT88 in the mid - late 90s, but a few infamous bad batches of the Teslovak (now JJ) tubes caused them to try and keep the more bulletproof Ei KT90. They then returned to the KT88 as they feel it to have better sonics. This was before Pierre was the distributor in North America. When I bought my JOR, Frank Garbie was the distributor.

I was speaking with Pierre last week. I was kind of surprised to hear that, like me, he likes the EL34 sound best. The issue of power with this tube is a lot less than one would expect. I guess the transformers may help here. The drawback is what you lose in the lower end, and it cannot be denied.

The newly released JJ KT77 really produces the kind of bottom end I demand. And, while its mids are not up to the incredible level of the JJ E34L tubes, it betters the JJ KT88. I see it as the best overall compromise in my DA60. In the DA30, I'm running the E34L tubes, even though it's an older unit, and should be only using the 6550, KT88, or KT90. I'm kind of trying to run them, then see how they measure, just to see if the fears of cooking that tube too quickly are actually true.

Again, I'm not a fan of Russian tubes. The Sovteks have a irritating sound, and the EH go way overboard on the politeness thing, which sounds solid state to me. The JJs have a house sound of vividness and brilliance that works best for me. Still, they will not be everyone's flavor. I ran the Ei KT90 in my JOR until I went to the JJ E34L, and while I lost bass and a little power, the gain in beauty and wow factor made me a Jadis devotee for life.

Interestingly enough, I am finding the current production of Chinese tubes to be fantastic. I would have never believed it, but they actually are surpassing a lot of the NOS tubes I have on hand. No one would have ever been able to convince me of that I can assure you. Even the older ones err on the side of richness, so I prefer them to the Russian tubes. The new Chinese tubes seem to have changed a lot of their construction, and have really upped the performance. They're no longer junk. Others I trust seem to feel this way about the KT88 the Chinese are making now, and VAC even supplies them as OEM, which is saying something if you know anything about the kind of person Kevin Hayes is.

Rolling the 12AX7 means trying different versions and manufacturers. Ei that Jadis supplies are about as good as most modern manufacture. Though I hear great things about the JJ 12AX7 (ECC83) and their new ECC803, though the latter is a higher gain tube. Lots of people like NOS 12AX7, the Telefunken Smooth Plate being considered the Gold Standard, and commanding the most money, even if I have found superior tubes in my experience.

Rolling the 12AU7 if you get a DA30, DA50S, DA60, or DA88S would follow the same pattern.

I had used the EL34s on my JA30s and loved their delicacy so much so that I kept the JA30s as a back up when I bought the JA80s. For more power and bass, I went with the 6550A on the JA80. However, my Wilson WHOW subwoofer is driven by a separate (solid state) amp. Perhaps, the EL34's bass limitation may not apply in my system. The crossover on the WHOW is at 53Hz. At what bass frequency did you notice the EL34s begin to give up?

Great Listening,
Trejla , I feel I need to try the JJe34l in my JOR.
Now do you suggest I get the DA30 intergrated and experiement with 34 and 77's? Like you I am after vividness and brilliance, nothing flat sounding like the EH KT88's.
Will the DA30 accept 77's?
I'm not really interested in rollojng the 2 pre tubes in the JOR, as the changes will be too small to notice.
Trejla, I'm will to give up bottom end for brilliance in the highs. I do not like flat mids/highs. So that would be the E34L tube for sparkling highs/mids, correct? I also like very analytical sound stage, nothing mushy/all jelled together. Like the EH88 did.
Trelja is the most knowledgeable resource about tubes that exisists in my web travels and I have learned much from his previous threads. That said, I would still only re-tube a Jadis amp directly from Villedubert. Unless you never liked the sound of the amp to begin with.
Yes I just talked with Pierre, he said the best Kt88's are those directly from Jadis, but cost is $$$. I'll stay with the 90's. You know when you pick one tube over another, quality tubes I'm talking about, class A sound, you give up something for something else. What the 90's have the 88's lack, and visaversa. From talking with Pierre, the DA30 gives more power than the JOR, but I really don't need more power.
I'll stay with the JOR and get the Cayin 88 as a second amp.
The 88's in the cayin should be on the level that Jadis uses in their amps. And may be better than the EH and JJ tubes.
I'll post a note when the A88 arrives, mid summer.
Jadis tube lover that I am, now understand my devotion to the SS SOTA: Hovland, hand built locally, customizable, accessible, affordable, dependendable, reliable, predictable. What's not to love? Just the tax and duty added on to the tubes from France for one.
Bartokfan ; I would be interested in your findings with this tube thing . Or anyone else for that matter . I have just purchased a Cayin a88 . This is my first true voyage into the tube world and am trying to learn .
Does anyone know if the other tubes , mentioned above , such as the kt90's , 77's etc. can be used in the Cayin a88 ? Has anyone tried ?
Signed 'Tube Noob' !
Saki I plan to stay with the Jadis tubes in the JOR. These are very expensive tubes and to get any quality that will equal these 90's will cost me a fortune. I suggest you stay with the cayin tubes, which are no doubt FIRST CLASS tubes. IOW don't go changing anything. What you can take a look at is your digital sourse and speakers. Do these 2 match up with the A88 quality. You gotta look at this system thing with some logic. Changing tubes isn't goning to make a class B speakers/digital sound any better.
Bartokfan ; I agree . I just acquired this amp with a pair of Ref 3a De Capo i's , which I auditioned together . So I was just thinking ahead , right now I am quite pleased . But we all know how long that can last !!! I would be interested in knowing what my options would be , when that time comes . Just trying to learn .
I don't think the Cayin is as versatile as the Jadis in accepting various tubes. btw did you feel obligated in buying the speakers with the A88? Which city do you live that has Cayin to audition?
No , I did not feel obligated at all . The dealer is in Clearwater, Florida .