2. amps-preamps
  3. 1146791949

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

Showing 2 responses by bezimienny

bezimienny OP
53 posts
 
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.
bezimienny OP
53 posts
 
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
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