We repair, upgrade and modify all JADIS preamps and power amplifiers. JADIS units have rather spotty parts quality. We see some really poor quality parts  in the same unit that has other excellent quality components. Most common failure areas are power supply and voltage supply to filament circuits. Soldering defects usually account for the rest of the JADIS work we do. The repair/upgrade option is the best choice for these units. We correct the original problem and replace any poor quality parts with upgrades. We treat each JADIS unit as a individual repair scenario and advise as to the best course of action for each individual repair/ upgrade.
We have had very good results with splitting the single chassis preamps into two,  choosing caps to match the customers sonic preference and some rather extensive modifications involving power supply and resistor/cap upgrade.

Please contact us if you have any specific questions about  your JADIS equipment