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Hi, I have successfully built a pretty great sounding Total Recall.

Everything works great except there is clock noise (high pitched whining) in the delays past about 3 o' clock on the delay time pot. This isn't a huge issue, except that I have spent so much time on this build, I want it to be ironed out.

I originally followed the calibration-by-ear instructions in the build document but when the clock noise issue surfaced, I attempted an oscilloscope calibration.

Not all of the readings measured the same as in this guide:
https://sites.google.com/a/davidmorrin.com/www/home/trouble/troubleeffects/electro-harmonix-memory-man/eh-7850/eh-7850-calibration

Specifically I ran into problems when trying to reach unity gain between pins 14/15 and 7 on the NE570. With the trimmers in their max positions, I can still only get about half the gain on 14/15 as I get on 7.

I don't know if this issue is related to the clock noise issue, but I'd love to get input on these issues.

Things I've tried:

reduced C40 to 220pf (this didn't seem to change much)
replaced the compander (tried SA571, NE571, and NE570 with little to no difference)

Thanks in advance for your input!

Thanks everyone!

Matmosphere: good point. Troubleshooting could be tough with this one, especially because transformers don't make total sense in my brain yet.

danfrank: ...and you've convinced me. This was my biggest fear going into it.

However, my curiosity is still piqued. Would anyone care to weigh in on how this should be done? I'm no longer interested in doing this in my pedal, but because it's mentioned in the build documents I would love to know how it'd theoretically be accomplished.

Thanks again!

Yeah! Snug as a bug in a rug. I'll actually put it in "sideways" with the legs of transformer bolted to the "back" of the pedal, where the jacks would be located. I also have a grommet for the AC line. But also, if transformer wiring is going to be a headache and I just need to do another wall-wart, so be it. Also, I don't want the transformer if it will introduce noise, hum.

Any advice, opinions?

Hello all, first post here.

I am finishing a Total Recall board and I'm at the power testing phase, but I cannot decide whether I should go the route of the wall wart or wire an AC transformer in the box.

I have the materials to do either option (I think):

LM7915 regulator for wall wart option
F-115x transformer for AC line option
https://www.mouser.com/datasheet/2/410/F_115X-780782.pdf

I have two basic questions:

1. Which option should I use? I HATE wall warts, and the rest of my pedal chain is powered by a OneSpot. I don't love the idea of having another big ugly wall wart to plug in and carry around. I would prefer a regular AC plug for the aesthetics and ease of transport. I'll be putting this circuit in a 1590DD so I'm not too worried about room. Does the transformer introduce more noise than the wall wart? I assume this depends on filtering...which brings me to my next question...

2. How do I accomplish the AC wiring? I have been studying the original 5-knob schematics to no avail. https://sites.google.com/a/davidmorrin.com/www/_/rsrc/1424104730679/home/trouble/troubleeffects/electro-harmonix-memory-man/eh-7850/EH_DMM_7850_schem.jpeg
I see the filtering, but there is also a rectifier (I think) and a zener (?)...it's above my head lol. Is there an easier way to wire this up using the transformer I bought and the regulator on the madbean board? I assume I'd need a rectifier and filtering. I could just use four 4001s and some electrolytics, no?

I hope this wasn't too long a post or too confusing. Thanks for any assistance and advice!