Marcel Duchamp wrote: > Of course, I meant > "Try removing R9 - this will change the gain of the input amp from +2 > to +1." Try again. The original gain of the input amp is +5. Also just removing R9 won't make a unit gain stage, but a oscillator. TL072 are not unity gain stable, despite what some sources claim. ******************************************************************** Embed Inc, Littleton Massachusetts, http://www.embedinc.com/products (978) 742-9014. Gold level PIC consultants since 2000. -- http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist