Mine uses EF86 tubes. Like Ejmac70, over the 20 plus years I've had Jadis preamps I have preferred the sound of Telefunkens in these units, both EF86 tubes in the JP200 and the 12AX7s in my previous JP80MC. I tried Mullard 12AX7s for a while in the old preamp and felt they were brighter but not as well-balanced tonally; if you use this type tube you might try them to get that added "sparkle", though I too feel it's more brightness than sparkle. Other good EF86 tubes I have used in my current unit are NOS tubes from GEC and Amperex; these have sounded excellent and I consider them on a par with the Telefunkens in my unit. I have in reserve, but have not yet used, some Electro Harmonix EF86 tubes intended primarily for guitar amplifier applications--some day I'll try them, I imagine they might give a brighter overall presentation.
As an aside, I also agree with Ejmac70 about being careful about modifying Jadis equipment. Other than Andy Bouwman's "Romantic Era" mods he made to my JP80, I have not heard any mods to these units that don't lose the Jadis "sound" that you pay the big bucks for.
As an aside, I also agree with Ejmac70 about being careful about modifying Jadis equipment. Other than Andy Bouwman's "Romantic Era" mods he made to my JP80, I have not heard any mods to these units that don't lose the Jadis "sound" that you pay the big bucks for.