Jadis DA60

Thanks for your responses.

I naturally always have a load connected.

I myself have wondered why the fuse does not blow to protect the amp. The tech at the one Jadis dealer in Sydney said:

"It is true that there is never enough current to go through the valves to "burn out" the output transformer as such. In the instance of Jadis DA60 each valve is protected by a 200mA fuse, which means that if a current of more than 200mA going through, the fuse will blow.This is the theory. But in real life if one of the valve develops a flashover inside the envelop, it may not be high enough current to burn the fuse but the spike will cause a very high voltage back EMF on the primary of the transformer, which adds on the over 470 Volts already there, can and will puncture the thin layer of paper separating the layers of windings between the primary and the earthy potential of the secondary of the transformer."

Does that sound reasonable to anyone?

The transformers are not warrented for life, however Jadis in France did cut me good deal, but having said that they are still expensive.

Hi. I'm from Sydney, and own a Jadis Orchestra Reference; prior to this I had tube amps from Audio Research - these had problems repeatedly. Audio Connection, while very polite and helpful, could not solve the problems - the technicians seem prone to blame any problem whatsoever on "the tubes". I've also had warnings that the "wrong tubes" will "blow the transformers" - frankly, the technician did not seem altogether familiar with recommendations straight from Jadis - thus the Orchestra Reference explicitly is built for KT88s,KT90s,along with EL 34s, but the tech guy said the former tubes would blow the transformers (the original Orchestra was, indeed, built solely for the lower output tubes; but, hey, he had my amp sitting right in front of him, so he knew we were discussing the Reference). Needless to add JJKT88s performed flawlessly for two years.

Given your story, my advice would be to sell the DA60 back to Audio Connection, and trade to something new with a warranty - it's worth asking Joe to give you an extended warranty, which he might well do for free. Otherwise you might well end up throwing good money after bad. Alternately, have you considered shipping the amp back to Jadis for repair work?

All the best,
Rob

I also live in Sydney. email me offline and let me know who the technician is. If it is the same guy, he is very experienced and knows what he is talking about.

If not I will give you the othertube guys details

cheers

I quote an email from Jadis to me:

dear Sir
the DA 60 can work with all this kind of tube
after the choice is a question of personal taste
on my side I like the KT88 GENALEX because Ilisten a lot of jazz and voices I like the warm in the high frequency
for big orchestra the KT90 are more dynamic and have a very good control of the bass but the high frequency is less sweet
best regards

So I bought two matched hand matched quads of Genalex KT88 and supplied them to the Sydney dealer who is doing the repair (new output transformer, caps, resistors etc). They completed the rapair and returned the amp but have refused to give me a warranty on the work because they say the DA60 cannot use KT88s. They further say that in all likelihood that the KT88s will destroy my amp beacuse of the extra current draw and heat generated over 6550s.

When I drew their attantion to the fact that the recommendation to use KT88s came from Jadis, I was told by the boss that the their tech new better than Jadis.

So I fear that rationality has left the building and has been replaced with bluff, bluster and bs.

I welcolme any comments.
_

Jadis DA60 can use any tube among the EL34/6CA7/KT77 and 6550/KT88/KT90 variants. Jadis says it themselves, and I've done so as well in mine with no problems whatsoever. Why do you need anything more than what the people who build the amplifier have to say on the matter?

For the record my preference is EL34 first, KT77 second, then KT88, but that's why they make vanilla and chocolate. Use whatever sounds best to you knowing that the amp will play beautiful music with no issues whatsoever with your choice. It's difficult for me to think of a better, more musical amplifier than the Jadis integrateds.