I (only) get bypass tone both when pedal is off and on / Clandestine preamp

[m00ni]

Hi there,

When building my first PedalPCB pedal, I encountered the weirdest problem - or at least this is quite weird for this beginner

The pedal in question is the Clandestine Preamp and I’m building it from a kit I got from Musikding. Initially, soldering everything in place was easy enough, although I messed up wiring the switch at first as I expected it to be wired the same way the switch from a different non-PedalPCB kit I had just completed. After redoing the soldering on the footswitch, first I tested the pedal outside the enclosure. I only tried it for a brief moment, but noticed that led went on and that the pedal gave me the effect I expected it to: distorted tones sounded slightly smoother and everything in general a little prettier. I was so excited that I don’t think I tried adjusting the gain pot, but at least the 3-way switch had the expected effect on the tone. Also the trimpot for bias worked as expected.

Next I stuck everything in the enclosure. It was a tight fit and I noticed that I had left some of the wires too long. Before turning the pedal on, I, again, got a normal bypass signal. Next I turned it on. The led went on, but I only got the bypass tone even with the pedal on. Turning the pot or trying different switch positions did nothing. I tried to adjust the internal trim pot, but that too did nothing.

I opened the pedal and noticed that one of the wires had come partly off. That didn’t surprise me - I almost expected this. I cut the wire shorter and soldered it back. I fired up the pedal again and the same thing happened: all I got was the bypass signal regardless of whether the pedal was off or on. I opened up the enclosure and double checked everything. Everything seems fine now visually. I’ve now checked the pedal for grounding issues. The soldering could be prettier, but it should be ok. The wires should be ok too.

I’m thinking all this points to something quite specific, but being very much a beginner, I have no idea what it is. Any ideas? I’m hoping there’s a simple solution that doesn’t require me redoing everything.

I know a multimeter would help the troubleshooting, but I don’t own one yet - haven’t really had the need for one yet. I also know it would appropriate to post photos, but after struggling with the pedal for so long, I’m too exhausted to do that now (if I had any hair, I probably would have pulled some off ) In any case, I can post some photos tomorrow, if requested.

 

[jimilee]

Hi there,

When building my first PedalPCB pedal, I encountered the weirdest problem - or at least this is quite weird for this beginner

The pedal in question is the Clandestine Preamp and I’m building it from a kit I got from Musikding. Initially, soldering everything in place was easy enough, although I messed up wiring the switch at first as I expected it to be wired the same way the switch from a different non-PedalPCB kit I had just completed. After redoing the soldering on the footswitch, first I tested the pedal outside the enclosure. I only tried it for a brief moment, but noticed that led went on and that the pedal gave me the effect I expected it to: distorted tones sounded slightly smoother and everything in general a little prettier. I was so excited that I don’t think I tried adjusting the gain pot, but at least the 3-way switch had the expected effect on the tone. Also the trimpot for bias worked as expected.

Next I stuck everything in the enclosure. It was a tight fit and I noticed that I had left some of the wires too long. Before turning the pedal on, I, again, got a normal bypass signal. Next I turned it on. The led went on, but I only got the bypass tone even with the pedal on. Turning the pot or trying different switch positions did nothing. I tried to adjust the internal trim pot, but that too did nothing.

I opened the pedal and noticed that one of the wires had come partly off. That didn’t surprise me - I almost expected this. I cut the wire shorter and soldered it back. I fired up the pedal again and the same thing happened: all I got was the bypass signal regardless of whether the pedal was off or on. I opened up the enclosure and double checked everything. Everything seems fine now visually. I’ve now checked the pedal for grounding issues. The soldering could be prettier, but it should be ok. The wires should be ok too.

I’m thinking all this points to something quite specific, but being very much a beginner, I have no idea what it is. Any ideas? I’m hoping there’s a simple solution that doesn’t require me redoing everything.

I know a multimeter would help the troubleshooting, but I don’t own one yet - haven’t really had the need for one yet. I also know it would appropriate to post photos, but after struggling with the pedal for so long, I’m too exhausted to do that now (if I had any hair, I probably would have pulled some off ) In any case, I can post some photos tomorrow, if requested.

Absolutely, post photos clear, well lit and closeup. Show the off board wiring as well. I bet we can make it go vroom.

 

[chris.knudson]

It's been my experience that when it works unboxed and quits working when it's in the enclosure, it's usually something shorting to ground, but without photos there's no way to know what the problem might be.

 

[jwin615]

Theres a 44.376% chance the footswitch is borked.
It may have last gasped on the bench

 

[Locrian99]

Check to make sure you have your input and output jacks right as well. The in as the out can sometimes cause this.

 

[m00ni]

Hey all,
First of all, thanks for your replies and willingness to at least try to figure this out with me. Earlier on today, I had some time to take the board out of the enclosure and to resolder the led and the connection to power. I tried the pedal again outside the enclosure (straight to my Ua Apollo without effects) and it worked, to a degree anyways: the switch worked, the gain pot had an effect, though it was at it’s loudest at minimum setting (I thought maybe had to do with the fact that I hadn’t done any biasing yet).

Later, I turned to the board around just the tiniest bit to try to get a reading with an antiqued multimeter I got from my father-in-law and to do the biasing. I didn’t get a reading, but thought that maybe the multimeter just didn’t work. I tried the pedal again, still outside the enclosure and it had gone back to the way it was before: the pot and the switch don’t work and all get is the bypass signal with the pedal on.

Here’s a few photos. Gotta say, especially the backside of the board looks quite bad in this light. The footswitch isn’t too pretty either..

In any case, my best guess is that something is shorting, but I can’t see or figure out what it is.

 

[chris.knudson]

The first thing I noticed that seems suspect is the footwsitch. You have it soldered (upside down) to a break out board. The way you have it wired seems correct for a true bypass pedal, but by connecting the switch lugs to the breakout board, it seems to me that you are connecting both your input and output to ground when not in bypass mode. If you have another footswitch, I'd rewire it without the breakout board (i.e. connect the wires straight to the lugs). If you are going to use the breakout board, you need to flip it over so that the part that says "footswitch goes here" is on the footswitch side of the board.

I'm suggesting a new footswitch because I doubt that you'll be able to desolder that one without destroying the switch. Unless you have a hot air rework station, you're going to have a hard time getting all 9 solder lugs hot at the same time without melting the switch.

 

[Erik S]

you are connecting both your input and output to ground when not in bypass mode.

I wonder if just severing this trace would do it?

 

[chris.knudson]

I wonder if just severing this trace would do it?
View attachment 62891

That could work

 

[m00ni]

I did wonder what the breakout board was for and why I was supposed to do the more complex wiring on top of it instead of making the short/direct/matched connections between the two boards. There were no instructions for the breakout board, only the general PedalPCB guide. So I did my best interpretation of situation, went ahead soldering and messed it up, apparently. Needless to say, I feel like an idiot.



Am I right in thinking (guessing) that the breakout board was supplied as a nice extra that I could use to simplify things instead of doing the more complex wiring on the lugs?

 

[chris.knudson]

Don't feel like an idiot. We all make these kinds of mistakes -- and that's how we learn. Yeah, the break out board is there to simplify the footswitch wiring, but it looks like you figured out that part on your own, so kudos for that. I'm still not convinced that that is the whole problem based on your description, but it's where I would start.

 

[szukalski]

We've all made these mistakes. Sometimes you poop your pants at home, sometimes it's at the local pool.

 

[m00ni]

I wonder if just severing this trace would do it?
View attachment 62891

”do it” as in make it work? If yes, I’d be happy to do it. How do you suggest I should do it? Explosives? Right now, I feel like I’d be up for that, haha.

I started this hobby partly as a therapeutic thing to balance hectic professional and family life. It worked well until now

On the other hand, I’m quite sure I won’t repeat these mistakes with the next one I build. So yeah, I guess this was a learning experience.

And if severing that one connection in the footswitch doesn’t work, I can buy a new switch from Uraltone, a local shop here in Helsinki. Their diy kits are well liked and worth checking out, especially if you’re based in Europe.

 

[chris.knudson]

”do it” as in make it work? If yes, I’d be happy to do it. How do you suggest I should do it

Yes, cutting that trace might make it work. You can "do it" a couple of different ways. One way would be to use a box cutter and cut through it in two places and scrape the trace off the board in between the cuts. You don't need to remove it completely, you just have to break the connection. The other way would be to use a drill bit and drill through the trace, just be careful not to drill all the way through the board and into the footswitch.

I’m quite sure I won’t repeat these mistakes with the next one I build.

Don't worry, you'll make plenty of mistakes along the way -- we all do. I've actually done the exact same thing that you did, only mine wasn't on a breakout board. It was on a finished PCB. I didn't realize my error until I tried to put it in the box, and the components were sticking out of the case to the point where I couldn't get the back on the enclosure. I ended up destroying the footswitch and the PCB trying to desolder it.

 

[m00ni]

Yes, cutting that trace might make it work. You can "do it" a couple of different ways. One way would be to use a box cutter and cut through it in two places and scrape the trace off the board in between the cuts.

Cool, thanks, I’ll try to find the time to do this tomorrow! Will let you know if it works.

 

[m00ni]

Just got around to severing the trace and it appears it fixed the problem! Now I can really hear the effect and everything, including the gain pot, appears to work. I can’t really do any soldering today so I can’t box the board, but I’m quite confident it’ll work once I get to it later this week, probably on saturday.

I actually built another pedal (Guardian OD) right before with the Clandestine preamp. That didn’t really work either and I had given up on it as I thought I had messed it up beyond repair. In the end, it seems that everything was fine besides the footswitch which I had wired the same way. I severed the same trace in that one too, which brought it to life. I’m very happy with the way it sounds and everything works great, except for the LED, which won’t turn on. It worked when I first tried the pedal on. After that I tried some random fixes to fix non-existent problems, which, I think, only ended destroying the LED. Or is it common that LEDs get damaged because of issues with somewith else, for example with the footswitch? I’m quite confident I didn’t touch the soldering on the LED legs while trying those other ”fixes” and the soldering there looks passable. I’m wondering if I should look for some other wiring issues or just go ahead and buy a new led the next time I shop for something else and try that one.

In any case, thanks so much for the help so far!

 

[chris.knudson]

Awesome, I'm glad that did the trick -- definitely a lot cheaper and easier than having to redo the footwsitch.

As for the LED, your footwsitch wiring may have bypassed the current limiting resistor, which may have fried it. The only way to fry an LED is to put too much voltage across it. Also, if you have it wired backwards, just won't work. If you have a DMM, you can test it.

If you can post some photos, I'd be happy to take a look.

 

[m00ni]

Just reporting that the Clandestine preamp is now boxed and not only does it work perfectly, it sounds very, very good, too! Though it was a bit of a struggle, I’m really happy with the pedal. Thanks again for all the help and suggestions!

I think I have an idea of what’s wrong with the led in the Guardian od. I’ll try fixing it later on.