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
rcprince
3,080 posts
 
I would probably ask Pierre Gabriel or Jadis the question. If you don't have pre-out/amp in jacks on the back, you probably couldn't do this without major surgery. What output tubes do you use in the JOR? You might try KT88s, if you're using EL-34s, you lose a little midrange magic but get a bit more power. I'd choose them over KT90s or 6550s.
bartokfan
664 posts
 
Yes that is what Richard Grey told me, that it would be major tweaking to supply a preout.
Richard did say the KT90's add abit more bass over the 88's.
I'm not going to switch tubes, just seems a better option is to upgrade to the Cayin. I mean whats a good pre going to cost you? 1K? Throw in another 500 and you get the beefer Cayin.
Makes more sense to me.
mcfarland
356 posts
 
I have a JOR and gave it to my wife. The JOR has a PASSIVE pre-amp section with no gain. I used a Rotel tuner/pre-amp so that she can have the convenience of remote control. I have the JOR's gain control at about 10 or 11 O'Clock, if that helps you. Everything seems to work just fine and has been for several years in this set up, driving Triangle Titus's. The CD player plugs into the Rotel, so that the Rotels remote controls everything except power on and off.
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.
rcprince
3,080 posts
 
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.
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