Jadis Orchestra Ref + Pre-Amp?


Wondering if it is possible to use the JOR as a power amp, with a Pre-Amp and CD feeding in, and whether this would help with the avoidance of clipping - I have no background in electronics, so I'm unsure whether the pre-amplifier boosts the signal in a meaningful way, and if so whether this translates to an easier time for the JOR - the issue at the moment is with solo piano music, where there are large changes in dynamics and a crash of chords brings distortion, which sounds like clipping, albeit 'soft' clipping; needless to add turning down the volume prevents this problem, but then I'm listening at a lower volume level than I've been accustomed. I was warned about the amp being a bit underpowered for the difficult load my speakers represent (Wilson Cubs) - distortion never occurred with a previous, more powerful, ARC amp (D125). I still have an ARC SP9MkIII pre-amp.

If the above is possible, would it be preferable to run the JOR with the gain wide open, and use the pre-amp to attenuate volume, or the other way around?

Thanks for your anticipated help.
Rob.
bezimienny
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
Bez, the weak link in your system in not the JOR, it is with these Wilson Cubs. Not sure what apeaker you are refering to, did not see it on wilson's web page.
I heard 3 Wilson models 3 yrs ago in a showroom and was not impressed in any way. One of the worst speakers I've heard.
And "didps below 3 ohms", I can believe it and would never hook anything unfriendly to my JOR.
Let me ask you did you buy your speakers first , THEN the JOR?
You did it backwards. Buy the amp first, then look around for speakers.
Look at Bbro's line of speakers he uded on the JOR. Thats punishment for a little tube amp, yet the JOR worked the load.
The JOR will deliver high dynamics on the right speaker.
In any system, there are 3 sources for coloration/fatigue.
Amp/speakers/cdp. The object is to find the least coloration/distortion in each category.
If one of the 3 is of poor sound, it will drag down the other 2.
Paul