SID groovebox from MM and others commercial SID synths (Page 2 of 2)

KIT, no. They had sold some kits awhile ago, but everything is SMD so most ppls don't/won't like soldering QFP chips.

Not exactly EMU, more like a reverse engineered chip design. The FPGA is a 'sea of gates' that lets you design logic circuits. Can be defined as a schematic or as a logic equation in a HDL language. Kind of like writing a program, but you are describing the logic design (inputs, outputs and the truth table), and the chip interconnects the needed gates.  Like a really big GAL that you can reset easily.

The RetroArcade has the HDL bitstreams and GUI already setup, so the user can treat the running hardware as a synth. Of course one could make changes at the hardware level if they chose. There is a GUI to interact with the boards, over a USB connection and/or send MIDI. But, in the end the 'SID' or 'AY' is a redesign based on how the original preforms. Not having the original die design for the chips, the 'soft cores' are not 100% copies of the originals. It's the same with the clone consoles that are hitting the market, ASIC designs to recreate the originals, sometimes they don't get it right.

  Very little learning curve for this application, the user just uploads the bitstream the first time, it's stored in flash on the board and thereafter gets loaded into the FPGA after every power cycle . The real strength with FPGAs is the way you can reconfigure it; at one time, you could have a 'SID' synth and then upload a FATMAN synth, or a PacMan game, or your own design. Most of the users of FPGAs are interested in logic level designing; and the 'chip' scene, at large, is interested in the originals.

For example synth designs, take a look at http://jovianpyx.dyndns.org:8080/public/FPGA_synth/
Scott G's designs are closer to analog synths and show the power of FPGAs.