Jadis Orchestra Ref + Pre-Amp?

I assumed that since the pre-amp section is passive, all the volume control is doing is decreasing output by adding resistance - put the volume control on full gain and the JOR is basically operating as a power amp: if this is incorrect, please let me know.

An active pre-amp presumably amplifies the source signal to some degree, but I am unsure whether this translates to an easier time for the JOR - also whether the amplified signal is actually going to put a strain on the JOR input circuitry.

The distortion is really only limited to passages of classical music, generally solo piano, where virtual silence is followed by fff chords. The Wilson speakers dip to below 3 Ohms, and this, apparently, is the cause of the difficulty. The previous 110Wpc ARC D125 had no problems with the above.

At the moment I am not in a position to change speakers. I just happen to have kept my ARC pre-amp so adding it in would be simple and pragmatic, if indeed this is possible.

Any further comments would be welcome. Cheers,Rob.

I suppose, if the preamp section of the JOR is truly passive (I seem to recall reading somewhere that it might be an active solid-state unit, though, so that's why I'd ask Jadis), you could try your ARC preamp running into the Tape In input (or for that matter, I guess any input) and seeing how it sounds. The losses in transparency might be offset partially by the additional gain. But I'd keep the volume on the ARC very low at first, and gradually build it up, to make sure there's no overload problems.

Hi Bezimienny. While I haven't tried the JOR I have an integrated with a passive pre section and I have tried exactly what you mention above. Open the volume control full, connect a pre in into whatever input of your choice on the integrated, (obviously make sure you've selected that "source" on the JOR), and voila. I started with the volume off on the pre because I wasn't exactly sure what was going to happen. Anyway, it worked for me. Don't know if it will work for you, caveat emptor, don't try this at home, blah, blah, blah :-)

I was just goofing around and didn't really evaluate the sonic benefits however.

Finally, I have been told that you run the integrated full open and the pre controls volume, not the other way around. If you can borrow a pre to try, just be careful and why not give it a whirl. That's my 2 cents.

Bezimienny, I believe Russ (Rcprince) asks the relevant question - what output tubes are you using? If you are using the EL34, you will gain a bit more extension using KT88.

Next question, when was the last time you biased the JOR? As the tubes age, I found the bias settings must be inched up accordingly.

Also, are your output tubes fresh? After 6 years with the Ei KT90, I had one short (causing no damage to amp or speakers), and I had to account for it by really pushing that channel harder. It wasn't until after I got a tube tester did I realize what the true problem was.

Biasing is of critical importance with the JOR, and a guy I met here in the threads was having a lot of problems with his. Lots of distortion and a crackling sound. Turns out the problem was the amp needed to be biased, and my original instructions he was using were not correct for all of the tubes. After he sent it to Avi Brand (US Service rep), everything was fine. I called Avi to confirm the correct bias procedures.

If you are using the Ei KT90 or a KT88, and the JOR is properly biased, then the amp needs an easier load to drive than your Wilson Cubs.

Paul, you are using the JOR with the tone controls at 95%??? I found if you go past 25% either way from flat, it SERIOUSLY alters the sound for the worse, completely changing the character of the JOR. Not that my flavor is the right one, but I found flat treble, and 10 - 20% more on the bass was often where my comfort zone was. Though I could still hear the deleterious effects of the tone control as compared to flat, the bass boost was welcome.

Thanks for the comments. I think the general gist is that while the above is possible, it probably is not a great idea.

Hi Trelja - the JOR has KT90s - the distortion occurred from the get go, that is directly after purchase. In fact one of the factory KT90s developed a (completely different and continuous) crackle a month later and the store owner took it upon himself to change the whole lot and have it rebiased - the distortion on loud piano passages remained, although the unit has been completely trouble free, in terms of any continuous crackles etc, since. I love the sound - it really is just this isolated issue, although it is important in that I listen to solo piano frequently.

To be fair, the sales staff warned me about the JOR struggling with the Wilsons - I auditioned a Defy7MkIV first, along with an ARC VS110 and a Gryphon SS power amp - the Defy was fine, but very expensive; the JOR sounded better than the others. They mentioned the larger Jadis integrated, which I think you own, but they did not have one on hand to audition - it too is very dear here in Australia (and probably elsewhere) - the JOR was one third the price and we have impending home renovations, so I accepted the compromise - and, in the main, a very nice compromise it is.

Cheers, Rob