upgrading JADIS JA-200, JPS2 and JPS3

Andy's principal changes were in using vintage resistors throughout the units in place of the stock resistors. He did not change any capacitors, except in the amps (where he put in a couple of vintage oil caps), and I'm not sure where they were used there. The AN bypass caps, as I recall, came just before and after the attenuators in the preamp; only a few were used, in areas that Andy (a) could fit them--they're large--and (b) felt they would make the most difference. Jadis used to use their own caps in the preamps (they were black) till the early 90s, then they switched to Phillips caps (blue), which were reputed to be a little more transparent.

.. I agree with Rcprince. IMO, Simply dont do it,if not satisfied with the Jadis sound sell .You mess with it and your sound as well as the resale value goes south real quick ..**Jadis owner since 1995**

Jadis models last for many years - your JA-200 was introduced more than 20 years ago and the circuit dates from the 60's - I have the schematic of the original Loyez amplifier in a Millerioux application note from 1966. The type of capacitors changed during its life.
Using better electrolytic capacitors will surely improve the performance of your units, but the choice of signal capacitors are less obvious - they will sound different but it is very difficult to foresee what will be the effect in your system.
Some people I know and respect enjoy putting V-caps in Jadis and claim a much better performance, but I never compared them with standard units. Also, most high quality capacitors need 200-400 hours burn in time before they reach a stable sound, making decisions less clear.
How old are your units?

Thegreathunter007 ..Do your self a favor and call Brooks Berdan in Monrovia CA.He is Jadis as they say!!.Ask him what happens when you replace something as simple as caps with non original Jadis..

Hi Microstrip, my units date from before I purchased them in 1994... at this time there was not even a protection fuse! I use old Kimber KCTG interconnects and a Kimber black pearl speaker cable with maggies 3.5 (sorry, I went to Africa eight years and did not follow technological innovations>>>joke)
Even Jadis folks evolve, for their new anniversary version of the 80 family they changed a few things, including capacitors (they look yellow...)...
Would be interesting to know which of these upgrades can be applied to the other models!