From what I understand the 202 is much the same as the 502? I've never actually looked at one inside or the schematic. But I have done a lot of mods to my 502 and it really sounds amazing now. You can send me an email and I can provide you with more details and links. Here is a link that Dave Ellis from Ellis Audio wrote on mods that he did. http://www.audiocircle.com/index.php?topic=17354.0 These will make a great deal of difference. At the least change the crappy 05 cent CBB coupling caps. You can try a preamp with the amp now. Just put the volume at about 1/2 and go from your CD to the preamp first and then into your Jolida input of your choice. It will give you a good idea what the preamp will sound like before you start removing things. Mainly the alps volume control. But you would need to add a resistor or two. Try what I mentioned before you go to the trouble. These Jolida amps can really be brought to a higher level if you put a little work into them.
Good luck and happy listening
Good luck and happy listening