> > Sounds like a practical device. Since the 12AX7 is listed as a valve the fetron replaces, It'd be interesting to see one in a guitar amp. :-) > > Joe, N6DGY > HI Joe That article states that the fetron was used to replace one of the 12AX7s in the early Mesa Boogie guitar amps - I didn't know that before. Phil M1GWZ