After reading the numerous threads describing the different mods for the 1212m, I've decided to mod the opamps and replace them with LT1364. Being new to this I have several questions. It looks like the card has a total of 7 JRC 2068 opamps.
1- Is it worth replacing all of them? Would it achieve better recording quality?
2- Is the procedure as simple as substituting one component for another or are there additional steps involved?
yes you can improve the ADC that way, however in that case another opamps can be better choices, namely AD8022 - that one gave the best results out of many tried before the same ADC like on 1212m, just on different card (ESI WT192X), but the input section seems to be taken directly from the datasheet, it should behave the same on 1212m.. the second best results were obtained by AD8620..