This project is cross between a Neve 33609 and the Chandler TG12413. the problem with the Neve is it uses germanium diodes with very small forward voltage and the signal has to be attenuated down to -40db to keep from having the diodes rectifying the signal. In my latest version I used Zener diodes with a higher forward voltage and didn't to attenuate as much. Zener diodes are tricky to work with so in a future version i might try using LED's....stay tuned