I have 4 of these cards. I want to use 3 of them with my DM4800. Two of them work great. The other two seem to have issues that when I assign anything to a bus assigned to particular outputs on the AES card all I get is digital noise. On one card it's 4 of the 8 (3 & 4, 7 & 8) channels and on another it's 2 (3 & 4) of the 8 channel that have this issue. I have tried swapping cables to no avail. I don't remember if I've tried swapping slots with the two working cards (I kind of don't want to mess with it). The cards with errors have been installed in slots 3 and 4. Same issues in both slots. I feel generally confident that the expansion cards are the issue and not the DM4800. Another thing I've noticed is that the two cards that I'm having issues with don't look like they're the same revision board. One of them has some components soldered to the board with heatshrink around them. I bought these cards one at a time over the course of upgrading from a DM3200 some years ago. The last two cards were ebay purchases from Europe. I haven't compared them with the two working boards. I'm in the USA. Does anyone have any experience with these cards?