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Old 27th Dec 2018, 3:05 pm   #4
Ian - G4JQT
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Join Date: Jun 2004
Location: Reading/Fakenham, UK.
Posts: 1,320
Default Re: Yet another 'Pantry' tx

Quote:
Originally Posted by TonyDuell View Post
Why is there no feedback on U1 (or U3, but the latter could be intended to saturate)?
Thanks for your thoughts. Unless I'm mistaken U1's feedback is via the tone control network, and U3 is just a voltage comparator - it conducts pulses to Q5 depending upon the setting of VR5. (Although it's quite possible I have miss copied from my old hand drawings.)

I shamelessly lifted those two circuits from '50 circuits using IC 3130'. Just found an online copy here: https://www.americanradiohistory.com...-ic-ca3130.pdf

Ian
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