Anthony. > Actually I think it's a 4075. Wonder what the difference is? I'm pretty > sure they both used the LM3900 though... http://www.arptech.synth.net/modmain.htm It seems, very little, the 4075 is a drop in for the 4035 personally, I've always fancied building Joachims 40235 module ;- http://www.arptech.synth.net/40235/index.html Paul