OWL pedal power/NRST pin

Hi folks, last night I suddenly started having what appears to be the problem described here, but the nRST pin isn’t labeled on the board so I’m a little lost.

Could someone point me in the right direction for where to solder the cap so I can power up the pedal again without having to fuss with plugging and unplugging stuff?


I think this may help - https://web.archive.org/web/20160915231413/https://hoxtonowl.com/mediawiki/images/e/e0/Owl-digital-pinout.pdf . It may be older board revision than you have, but it should be pin compatible for newer versions. You could double check by testing continuity with MCU PIN, or just wait for Martin to confirm this.

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Thanks! That internet archive link doesn’t seem to want to work for me, but I think I’ve found another version of the pinout in another post here

Well, I had to refresh it a few times to get it to work, their download server is often failing. Is the file you’ve found also for revision 5 of Owl digital board?

It was an image with a big old watermark over it, but the pinout generally seems to agree (that is to say, I retried the wayback link and refreshed it a bunch of times like you suggested, then compared them)

Well, although the symptoms were similar the cause doesn’t seem to be the same. I held a 150nF cap across the ground and nRST pins through a number of power cycles and got the same behavior as yesterday.

The only way to get the pedal to consistently power up is to unplug the Ojai, unplug the OWL, replug the OWL, replug the Ojai. I assume what’s happening is when I replug the OWL something is discharging, allowing the chip to properly detect power. It’s not the end of the world, but if anyone’s got a better solution I’m all ears

Hi @eugarps, have you tried using a dedicated PSU for the OWL? We find it causes less problems and reduces potential noise issues. I understand it’s not as convenient as a multi-plug though.

I have put the OWL Digital pinout up on the new documentation site, sorry it was so difficult to find! Rev05 and Rev06 have the same pin assignments.

Yea, I tried with a separate psu and there wasn’t a problem. The whole point of having the Ojai was so I wouldn’t have to fuss with multiple psus though, so I’d really prefer to not to do that (it’s a huge pain when there aren’t enough outlets on stage and we have to figure out a way around it)

Thanks for the link to the pinout by the way! I’ll double check that against what I was trying before

Well, it seems like I’ve made a fool out of myself. I tried the cap across the two pins again, and I’m five for five on bootups now. I have a sneaking suspicion I was counting from the wrong side of the board and the pin I checked against ground happens to be shorted to wherever I decided ground was.

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Cool, great it works!

Another thing that can be worth trying if you have PSU problems is adding a bit of decoupling capacitance, in the form of a large-ish capacitor (from 10uF to 220uF electrolytic) between ground and supply. Just make sure you put the (-) end to ground or it might pop!

We’re living in the age when certain country leader suggests treating infectious disease by drinking aquarium cleaning liquid. So counting PINs in the wrong direction does not qualify you for being called a fool - because it means you’re at least capable of counting things. You should try harder if you want to deserve this title!

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Thanks for the suggestion, I think I have a few larger caps around from when I was trying out different coefficients for my guitar’s tone pot.