The Jolida 202 uses basically the same circuit as the 302/502 (much different transformers) so any upgrades that work in these amps will also work in the 202.
For a few critical upgrades, I recommend the following.
1) Remove the volume and selector switch. Using it as a power amp with a good preamp in front of it will transform the unit. You will have to install a voltage devider to reduce the input level. I would recommend -6dB to -10dB.
2) Coupling caps -- whatever you like
3) Diodes - get rid of the $.02 silicon pieces and go with a decent Ultra Fast - Soft recovery type.
4) Power Supply Caps - A good Pansonic with low ESR.
5) Critical resistors - Cathode units with 5 watt Mills, Grids with good carbon comp or even the 1 watt Dale CW series.
6) If you goo with the triode mode, be careful. Any problems and you will fry the output transformers.
As always, be very careful inside any electocal component. There are voltages in there that can cause some severe problems. Your amp can be replaced, you can't.
For a few critical upgrades, I recommend the following.
1) Remove the volume and selector switch. Using it as a power amp with a good preamp in front of it will transform the unit. You will have to install a voltage devider to reduce the input level. I would recommend -6dB to -10dB.
2) Coupling caps -- whatever you like
3) Diodes - get rid of the $.02 silicon pieces and go with a decent Ultra Fast - Soft recovery type.
4) Power Supply Caps - A good Pansonic with low ESR.
5) Critical resistors - Cathode units with 5 watt Mills, Grids with good carbon comp or even the 1 watt Dale CW series.
6) If you goo with the triode mode, be careful. Any problems and you will fry the output transformers.
As always, be very careful inside any electocal component. There are voltages in there that can cause some severe problems. Your amp can be replaced, you can't.