At 4/21/2008 22:10, you wrote: >The 555 will do the job just fine... you need only configure it >properly, which for me ended up being the same circuit Hamtronics >used in their early COR-2 Board. Simply copy that circuit less >the hang timer portion and you're set. > >I wish I could claim credit for it... but the circuit design >was originally done by Hamtronics (Jerry). I and a few other >group members can Email you the diagram if you contact us direct >off the list. Most of us group readers via the web don't receive >email attachments through the yahoo groups anyway. > >The really nice thing about billing things from kits is how you >end up keeping good circuits around for use in other applications. >The COR 2 Circuit is a great circuit, wish they still made and >sold the kit, but now I "roll my own". > >cheers, >skipp
For some reason I never had much luck with 555s; the trigger inputs were so sensitive that they always glitched in my noisy high school-era circuits. I found the LM324 quad op amp to be much more stable & versatile. One section could be the COR, another the timeout timer, & yet another the audio amp/de-emphasis. Bob NO6B
