When I was referring to the the SRX circuit, I meant Jim's SRX Plus circuit. The original is pretty good, but Jim has taken it to an entirely new level. I don't often build other people's designs anymore, but the original SRX always intrigued me, and the SRX Plus has renewed my interest. I have a reputation for building "over-the-top" tube projects, but I actually find it a lot more fun to see how much you can do with simple circuits and limited resources. In the not too distant future I'll be building Jim's SRX.