There are two soft synths that I’ve become a fan of recently. The first one is Magical 8bit Plug by YMCK. This one sounds amazingly close to the original Nintendo sound chip. Closer than anything else I’ve ever heard from software. It’s easy to use and is pretty lightweight on the processor load. It’s available as a VSTi and Audio Unit plug-in.
The second soft synth I’ve been enjoying is Chip32. It also has an 8 bit sound similar to the NES sound chip. One cool feature of Chip32 is that it gives the user the ability to draw the waveform, updating it in real time. Brad from New Grey Area turned me on to this one and I’ve been using it for a number of electro tracks I’ve been working on. Also available as a VSTi and Audio Unit.