I had already talked to the author of the circuit about running it off the Crates 12.9 supply and all of the caps I've been using are rated at 25V. The TL072 are rated at a supply voltage of plus or minus 18V so running them off of the 16.5V supply shouldn't be any problem. The mods to the board are getting beyond my level but I'm studying the circuit and the specs and am slowly getting back up to par. May at this time just think about putting in a boost stage... Got to get off the paper and into the circuit. I'm no good at computer simulations... I have to be hands on. But man you have got my creative juices flowing.... There is an easter egg in the bloviator circuit I am missing... Just something I remember from a circuit I worked on years ago. Gonna dig out some of the old books and see if I can find it.