Audio Mods for the Jolida JD-100A CD Player

Not sure why you would consider modding a player that you haven't heard stock yet, but in any event there's plenty on this player in the archives. Do a search and I believe you will find that there are mixed opinions regarding the benefits of modding this particular player. Many believe that modding the player changes its character for the worse. If your budget is for the Jolida plus mods, I would just target players in that price range. Having owned the Jolida, I would suggest a used Cary or Audio Aero Prima, either of which will best the Jolida, IMHO.

I am in the same boat as you, I have a stock JD-100,and I want to mod it as well. I have never heard a modded unit, but I can't imagine why a moderate mod would make it sound worse. I rolled my stock Sovtek tubes, for some RCA 5751's and/later Sylvania 12ax7's, a minor improvement. The JD 100 has 4 el cheapo WIMA output/coupling capacitors after the tube stage, which are the only other important mod really IMHO. I really would like to put in some Hovlands, or some other highend cap. Years ago, I has Parts Connexion do an upgrade for my Anthem Pre 1 tube Preamp) which changed these SAME Wima caps for some Infinicaps, an incredible improvement. I suppose some better resistors, diodes might improve the power supply, but I want the most bang for my buck-- the wire, jacks, etc. seem very good quality to me, and the clock "upgrades" I am really wary of. I will probably use Response Audio for my mods, as he agrees with my theory and puts most of the money in the VH Teflon V-Caps.
Rest assured that the JD 100 is a great bargain and a wonderful, musical product. There is nothing else I know of near the price with a genuine tube output stage, instead of a bogus tube buffer. NO OP AMPS is a huge "mod" designed into the player, would you put op-amps in your Quicksilver Preamp's output section? The stock unit (with NOS tubes)has a wall to wall soundstage, harmonic richness, and makes music sound alive. Change out the caps and you (and I) should have a unit that will really be superior.

Bill at Response Audio mods Jolida http://www.bellaextreme.com/jolidacustom100.htm

An alternative to consider is this: I have the Jolida with only minor mods from Underwood. As opposed to mods of the unit I added a stand-alone DAC from PS Audio. I weighed the pros and cons of a $500-$700 mod vs a $900 DAC that would work with all sources. This includes a computer through the USB, Toslink digital in (DVD) and coax digital in (CD). There are many capable DACs out there. I find the Jolida to have a reliable transport and the jitter is quite acceptable for me and the PS Audio DAC III reduces the jitter to very low levels. It has turned out to be quite a nice combination. You also have to consider a quality coax and Toslink fiber-optic cables. The ones from Blue Jeans cable are quite good and meet all specifications. Good starter cables. Anyway, good luck. Sound advice is plentiful, let your ears be the best judge. Good luck!