Effects Layouts Odd One Out

Laundryroom David

Keyboard Cowboy 🤠
I’m troubleshooting a couple of recent builds of this one that have the exact same issue.

Has anyone else built this per the BOM?


If so, does anyone else get a loud hum when both the “bottom” and “edge” switches are engaged and gain is up past about 11 o’clock?

At full gain the hum sounds like an F (like 3rd fret on the D string).

Turning guitar volume down to zero has no effect, nor does running a buffer before or after the pedal. Turning the gain down on the pedal causes the pitch of the hum to go up a few steps and then cease once the gain knob is down to about 11 o’clock. Disengaging either tone switch (or both) ends the hum even with the gain dimed.

In other words, in stock OD-1 mode, it’s not an issue. In Fulltender mode with gain above 11 o’clock and both tone switches engaged, hum-a-palooza.

I cannot remember the last time I had to troubleshoot a build so extensively. I have inspected, tested, reflowed. Buffer in front, buffer behind, no other pedals in the chain, other pedals in the chain, different power supplies (Boss 9v, PP2+). I separated the input and output wires and isolated them as much as possible. Still no love.

Nothing gets rid of the hum and this is by no means a high gain pedal. My original Fulltender did not hum even with the gain maxed out and both tone toggles engaged.

I am wondering if there’s a problem with parts talking to each other through the rails or maybe some kind of feedback loop getting out of hand. I am (as I often say) not an engineer, nor do I even play one on tv so I don’t know if that even makes sense.

The closest thing I can liken this problem to is the way the havoc switch affects the sound of the Cannon Fodder MkI. Hence my musings about the feedback loop.

I am down the rabbit hole, tucking 47pF caps places in hopes it helps. I dunno man. Getting dark in here. Any help appreciated.
 
If no one else has built this, it may be faulty?
I know Members here use his PCB's, I had one that was a dud that has been built succesfully?
I put it down to faulty traces & I don't like the layouts so no more for me.
 
I’m troubleshooting a couple of recent builds of this one that have the exact same issue.

Has anyone else built this per the BOM?


If so, does anyone else get a loud hum when both the “bottom” and “edge” switches are engaged and gain is up past about 11 o’clock?

At full gain the hum sounds like an F (like 3rd fret on the D string).

Turning guitar volume down to zero has no effect, nor does running a buffer before or after the pedal. Turning the gain down on the pedal causes the pitch of the hum to go up a few steps and then cease once the gain knob is down to about 11 o’clock. Disengaging either tone switch (or both) ends the hum even with the gain dimed.

In other words, in stock OD-1 mode, it’s not an issue. In Fulltender mode with gain above 11 o’clock and both tone switches engaged, hum-a-palooza.

I cannot remember the last time I had to troubleshoot a build so extensively. I have inspected, tested, reflowed. Buffer in front, buffer behind, no other pedals in the chain, other pedals in the chain, different power supplies (Boss 9v, PP2+). I separated the input and output wires and isolated them as much as possible. Still no love.

Nothing gets rid of the hum and this is by no means a high gain pedal. My original Fulltender did not hum even with the gain maxed out and both tone toggles engaged.

I am wondering if there’s a problem with parts talking to each other through the rails or maybe some kind of feedback loop getting out of hand. I am (as I often say) not an engineer, nor do I even play one on tv so I don’t know if that even makes sense.

The closest thing I can liken this problem to is the way the havoc switch affects the sound of the Cannon Fodder MkI. Hence my musings about the feedback loop.

I am down the rabbit hole, tucking 47pF caps places in hopes it helps. I dunno man. Getting dark in here. Any help appreciated.
Yep. Mine did it too. I experimented with my components and got a “compromised” sound. It is late on the east coast, but I will look at what I used and post it here. I believe that I got it sounding good, and the switch works as expected.
 
If no one else has built this, it may be faulty?
I know Members here use his PCB's, I had one that was a dud that has been built succesfully?
I put it down to faulty traces & I don't like the layouts so no more for me.
Thanks I’m starting to think it may be faulty, which is too bad because the part that works sounds really good 😂
 
If no one else has built this, it may be faulty?
I know Members here use his PCB's, I had one that was a dud that has been built succesfully?
I put it down to faulty traces & I don't like the layouts so no more for me.
Yeah, I think I’ve devoted enough time to this and don’t see myself ordering more. Not worth the aggro.
 
For what it is worth, I was using a TL074. I changed C4 to 47nF and R10 to 15K.

I recognize that those values are near the stock values, but the changes made an audible difference in the direction of the original pedal. You can audition different combinations by placing the leads in the holes and jamming a toothpick beside the leads. That way, you do not have to solder, but can try different combinations.

Let me know if you find a combo that you like better. Good luck.
 
For what it is worth, I was using a TL074. I changed C4 to 47nF and R10 to 15K.

I recognize that those values are near the stock values, but the changes made an audible difference in the direction of the original pedal. You can audition different combinations by placing the leads in the holes and jamming a toothpick beside the leads. That way, you do not have to solder, but can try different combinations.

Let me know if you find a combo that you like better. Good luck.
Many thanks.
 
My build had the same issue. I tried lowering the value of R10 to change the amount of negative feedback, but I had to bring it down to 18K (maybe even 15K) to get the oscillation under control and by then, the tonal difference wasn't significant enough to justify the switch. I just cut my losses and ended up removing the bottom switch.

That being said, I've built many pedals using Effect Layouts PCBs, and it's the only build that gave me trouble.
 
My build had the same issue. I tried lowering the value of R10 to change the amount of negative feedback, but I had to bring it down to 18K (maybe even 15K) to get the oscillation under control and by then, the tonal difference wasn't significant enough to justify the switch. I just cut my losses and ended up removing the bottom switch.

That being said, I've built many pedals using Effect Layouts PCBs, and it's the only build that gave me trouble.
Try changing C4 to 47n. Together with R10 at 15k the oscillation was gone and an audible change for the switch.
 
My build had the same issue. I tried lowering the value of R10 to change the amount of negative feedback, but I had to bring it down to 18K (maybe even 15K) to get the oscillation under control and by then, the tonal difference wasn't significant enough to justify the switch. I just cut my losses and ended up removing the bottom switch.

That being said, I've built many pedals using Effect Layouts PCBs, and it's the only build that gave me trouble.

Yeah I cut my losses and binned both of the ones I built. I already built an OD-1 clone that I liked. The only reason I bought those boards was to build a Fulltender since I sold mine.

Entirely possible this is the only pcb in the shop that has a bug, but I won’t be the one to find out. Too many good projects elsewhere.
 
I've got mine working on the breadboard.. We'll soon see if it works when I solder everything together with the PCB. It sounds great so I sure hope it works.
 
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