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Jadis preamplifiers configuration

Gentlemen - such a didactic issue. 

In Jadis's offer, the phono stage + line stage preamplification can be built in several ways.


1. The simplest and most common is the two-box JP80MC preamplifier - both phono stage and line stage channels placed in one box plus a separate power supply for all that stuff. 


2. The second way is the JP200MC four-box preamp. In this preamp we have a line stage and a phono stage integrated into one box, but for each channel there is a separate box that has its own power supply. 

So we have full separation of L + R channels, with separate power supplies, but the phono and line sections are integrated within the given enclosure. 
There are also fewer filtering capacitors than in the third option and two times more ECC83 lamps are needed, which must be perfectly matched in pairs. These dual triode tubes probably work only one half. 


3. The last way - probably the least common, but very interesting, is a separate stereo phonostage JPS3 with a separate power supply and a separate stereo line stage JPS2 with a separate power supply.

In this system, we do not separate L + R channels, we only separate the phono stage and the line stage and we give each of them a separate, dedicated power supply. 

An additional advantage of this combination of JPS2 + JPS3 circuit is an additional 3 signal filtering capacitors for each of the preamps that are not in JP200MC, due to the lack of space. 

As for the electric circuit, all devices uses almost the same schematics, the difference is only in how we divide the circuits into individual boxes. 

In JPS2 there is another a single ECC82 tube on the CD input for which you have to ask the manufacturer whether it must be there. 


So the question is: what will give a better effect: dividing the channels and giving them separate power supplies, or dividing the preamplifiers and giving them separate power supplies? 

I will also add that in the channel splitting variant, the final effect will be as good as it is possible to pair individual ECC83 tubes used in the left and right channel (there are 12 (!) In total). In the latter version, JPS2 + JPS3, both channels are supported by a double ECC83 triode (6 pieces), which in turn must have internally paired halves. 

What do you advise - option 2 or option 3 and why? Variant 1 I currently have :-)
milimetr
rcprince
3,070 posts
 
I went from a JP80 to a JP200.  Tube matching wasn't as much of a problem as I had thought, as the separate volume controls could compensate for any lowered output, in practice.  Tube cost, of course, was another story, just due to the sheer numbers involved.  I found the JP200 just had an extra ease in the most dynamic recordings compared to the JP80, and imaging and soundstaging were substantially better as well.  One caveat--my JP200 was one of the few made that used EF86 tubes rather than 12AX7s and AU7s, which definitely gave a cleaner sound at lower volumes.  Another thing to keep in mind was that after the preamp my system at the time had separate active crossovers and amplifiers for each channel, so the benefits of one box for each channel were probably magnified in my system setup

Toward the end of my time with the JP200 I added a separate phono stage (first a Lamm LP2 Deluxe and then a prototype of the Merrill Audio Jens phono stage).  I preferred this arrangement to either of the Jadis phono stages, in large part due to the fact that, no matter how good the tubes in either of the Jadis phono stages were, they inevitably got noisy very quickly (and also wore out quickly too).  The Lamm and especially the Jens prototype (the latter of which is solid state) were much quieter and more dynamic and revealing.  

So I'm kind of mixed here as far as which I'd advise.  I'd say that in my system having the separate power supplies for each channel made the bigger difference in terms of dynamics and channel separation; having the separate phono stage made a big difference in terms of noise, but that is something that probably would not be as big a difference using the Jadis phono stage as opposed to the ones I used. I do think the phono stage's separate power supply also added additional dynamic headroom that I didn't get from the phono stage in the JP200, though how much of that is attributable to the different brands is something I couldn't answer.  If I had to choose one way or the other, I'd go with the JP200 over a JPS2/JPS3 combo (and I'd go with that combo over the JP80 by itself).

Not sure how much this helps; some others will probably chime in here as well. 
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