Another video on the DRX85, this time it's fully reverse-engineered. It took me two weeks to track every trace and component on the pretty complicated board, all done with no computer assist, taking notes on paper and drawing the schematics. Double-checking any WTF while also learning about the inner workings of analog-to-digital and digital-to-analog conversion. And all this insanity was built in 1986 - the same year Challenger crashed, Chernobyl blew up and I was born!

0:00 Intro 2:47 Shine Some Light 7:40 Other Board Examples 9:52 Block Diagram and Panel Overview 13:37 Bypass and Dry/Wet Mixing 14:27 Analog Section - Input 19:50 Echo/Reverb DAC Killer 21:07 Analog Section - Output 22:12 False Bypass? 25:00 It Was Madness! 25:59 Time Circuits 29:47 Changeover DAC Killer 30:40 Time Circuits Logic 33:07 A Trip Down The Memory Lane 35:47 ADC and DAC, Digital Feedback 45:00 Covers Go Back! 48:27 Some Conclusions 50:20 Let's Make Some Noise! 52:33 Thrash Metal Can?

Planning to make another video where I'll go over the inner workings of the digital part. Of course, after I get a grip on it :)

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