About as difficult as they come. Quite a few challenges. I built "Classic Style". End result? It works and sounds really good, especially the modulation.
Suggest read the build doc carefully before even beginning. Grok the PGE thing. Pay super close attention to capacitor dimensions. Make sure the SPDT switch is a "sub-mini". Consider an OPA2134 or something in IC1 because that op-amp is on even when the pedal is off (there is a TB wiring option). Love the top-mounted jacks. The doc is good; in particular the chart of IC pin voltages was great to have.
Calibration (by ear) process was not too bad. Sweet how all the trimmers are right up top! You do need an audio probe setup and having a looper pedal as source was invaluable. Ultimately, I was never able to completely eliminate all whine and crunchiness from the delayed signal (TP2-4) at max delay even with C31 under 200pF (max delay at that point is <400ms). However, it seems there's filtering after the BBDs to mute most of the whine, and the crunchiness is just what you get at long analog delays so I eventually resolved that I could live with a little noise at ~550ms in exchange for a relatively clean delay signal at ~450ms which is where I like my delay set. I really advise socketing C31 which controls the clock speed (there's no trimmer) and, as the doc says, make sure the DELAY pot is dead on 100K. I spent 2 days auditioning different values in C31 from 180pF to 340pf and finally settled at 263pF. For me this resulted in a clock period of 126uS at Max Delay (pin 10 on the 4047) and a Clock Range of 7.78kHz Max Delay 75.25kHz Min (pin 2 on the 3005s). Actual Max Delay is ~520ms.
This was Challenging and Fun and Educational to build. Nice feeling of accomplishment. Cold honesty though, I'm probably going to buy the new EHX Nano DMM which for around $200 runs on 9V and has a slide-switch for the True Bypass option.
Suggest read the build doc carefully before even beginning. Grok the PGE thing. Pay super close attention to capacitor dimensions. Make sure the SPDT switch is a "sub-mini". Consider an OPA2134 or something in IC1 because that op-amp is on even when the pedal is off (there is a TB wiring option). Love the top-mounted jacks. The doc is good; in particular the chart of IC pin voltages was great to have.
Calibration (by ear) process was not too bad. Sweet how all the trimmers are right up top! You do need an audio probe setup and having a looper pedal as source was invaluable. Ultimately, I was never able to completely eliminate all whine and crunchiness from the delayed signal (TP2-4) at max delay even with C31 under 200pF (max delay at that point is <400ms). However, it seems there's filtering after the BBDs to mute most of the whine, and the crunchiness is just what you get at long analog delays so I eventually resolved that I could live with a little noise at ~550ms in exchange for a relatively clean delay signal at ~450ms which is where I like my delay set. I really advise socketing C31 which controls the clock speed (there's no trimmer) and, as the doc says, make sure the DELAY pot is dead on 100K. I spent 2 days auditioning different values in C31 from 180pF to 340pf and finally settled at 263pF. For me this resulted in a clock period of 126uS at Max Delay (pin 10 on the 4047) and a Clock Range of 7.78kHz Max Delay 75.25kHz Min (pin 2 on the 3005s). Actual Max Delay is ~520ms.
This was Challenging and Fun and Educational to build. Nice feeling of accomplishment. Cold honesty though, I'm probably going to buy the new EHX Nano DMM which for around $200 runs on 9V and has a slide-switch for the True Bypass option.
