First post, by shock__
So let's start the year with something that might possibly be interesting for a few of you guys, as written in my introduction post.
I've recently found someone who is in possession of above card and might even trade/donate/sell the card to me. Considering the card seems to have virtually ceased to exist, with only 2 of them being known to me (apart from a few bbs/newsgroup posts from ~1990 or earlier) I've taken the duty upon me to start redrawing the card, so a scheme can be adapted from it later on.
Here is the current progress, which sadly still has gaps in it, considering I'm doing this based upon photos, with components/chips hiding some traces below them 🙁
Little explaination how to interpret this:
Violet circles: Holes for putting chips/sockets/parts in or VIAs (holes connecting front and back layers)
Blue traces: Front layer traces (sadly incomplete currently)
Red traces: Back layer traces
Violet traces: Front and back layers "overlapping"
White rectangles: chips (with Pin1 being marked and their identifiers)
Components like resistors/resistor network/caps/jacks aren't drawn in yet
Luckily enough, the way the SID-chip, which is pretty much the heart of the soundcard, is glued to the ISA slot can be seen already. Sadly enough this concludes the analog registers of the SID aren't incorporated in the design of the card and the adress decoding and implementation of the joystick port is still obscured. If you wanted to built a compatible on perfboard, one should be able to do so already tho, with a little thought. Once/if I get to finish above redrawing, a scheme will be posted, along with (if there's enough interest) eagle files so one can get this own SSI 2001 clone on a proper, neat PCB.
Funnily enough it seems the card indeed never was produced in larger quanitites, as the 2 cards I've seen pictures of have some minor changes to them. First of all, the card I got pictures of still has a wire thrown on top fixing a missing trace, secondly enough _both_ versions seem to have wrong caps attached to the 6581 SID chip (was 470pF in the C64, is 0.1uF on the SSI 2001), the amplification circuit being minorly different (1K-Ohm/10K-Ohm voltage splitter (which is how it's done in the C64 as well) vs. 10K-Ohm/10K-Ohm splitter) as well as the card I've seen have a "full" ISA slot connector (meaning all "gold fingers" are present) rather than just having "fingers" for the actual lines used.
Hope this might be of interest for one or another user and/or might help DOSBox development at one point, even tho it seems to be implemented just right already.
P.S.: The photos I got will be posted once the guy who currently owns the card has decided if he wants to keep it or not.