Tone Bender MKII DIY Help

[jwyles90]

Hey all! I'm working my way through my first DIY pedal kit and have hit a wall when it comes to figuring out what's wrong with it. When I turn the pedal on the LED lights up, but otherwise I'm not getting any kind of signal from my guitar when it's both bypassed or engaged. When the pedal is on however, if I turn the volume up (and attack too provided the volume is up) it just makes this steady, high pitched whine/hiss that gets louder the more I increase either the volume or attack. I went through and checked the wiring to see if anything wasn't grounded and as far as I could tell everything was wired properly (granted I'm new at this so I could be missing something or misinterpreting what I found). I took an audioprobe to the components at one point and couldn't even get a signal from that, so I'm at a bit of a loss.

Here are some pictures of the wiring, PCB, and schematic. https://drive.google.com/drive/folders/1mN0qF2-e-bib_bMYPs4rnR2IblxxXr1M?usp=sharing

[Kevin Mitchell]

Edit: My first answer didn't seem right after I posted. Can you confirm that you've wired the correct lugs for the input jack's ring and tip connection? I'm wondering if you've soldered ground the the tip lug.

And welcome to the forum!

[jwyles90]

Oh weird, I wouldn't have even thought about that being an issue. I got the kit from BYOC, so I just assumed all the parts sent over would work with the build.

Just to make sure I'm understanding correctly, all I would need to do would be to disconnect the wire that runs from the 9v battery clip to the input jack?

[Kevin Mitchell]

No sorry that was my mistake. It is the right jack. I just get confused easily  I updated my post probably as you were replying.

I was wondering if you had plugged in the tip & ring connections backwards which would ground the input signal. It's my only thought right now as your switch wiring looks OK from what I can tell though it's hard to make out the wiring near the jacks.

[jwyles90]

Ohhhh, I think I see that now.

Here's the wiring diagram for reference
http://www.generalguitargadgets.com/pdf/ggg_tb_m2p_lo_ns.pdf

The jack orientation on the diagram has the lugs facing inwards towards the enclosure, with the ring on the far left and the tip on the far right lug.

My jack is flipped around so that the lugs are facing out instead of the other way around, but the ring and tip are still wired to in the same way. So if I switched them that would make a difference?

Also on an unrelated note, do we always have to fill in these verification questions every time we respond? It keeps telling me I got the question wrong even though I didn't haha.

[edit to fix link]

[Kevin Mitchell]

That verification must be new and likely goes away after a few posts - once we know for sure you're not a robot lol.

Your link isn't working but here's an illustration of a stereo jack;


It's pretty straight forward.
Tip = signal, tip of the audio jack
Ring = ground, usually for stereo signal but not here
Sleeve = ground

Usually the ring connection is for a stereo signal but here it's used to connect the ground from the battery to the rest of the circuit only when an input jack is inserted - thus not draining the battery when you don't have anything plugged into the input. If you wired the tip & ring backwards then you're grounding the input signal and will not have guitar signal in either active or bypass mode.

[jwyles90]

Man, if that's what it is thank you so much for your help! I didn't realize each lug had a specific order, kind of just assumed that as long as I was wiring it individually it would be fine. Fingers crossed it all works out when I get home and rewire it.

Someone I was talking with about this last week said that in their experience the longer they spend trying to debug a problem the simpler the problem usually ends up being...I've been beating my head against a wall on this thing for a couple weeks now haha.

Here's the page I got the diagram from if you're interested. The diagram itself is a PDF which might explain why it isn't working: http://www.generalguitargadgets.com/effects-projects/fuzz-tones/cs-tonebender-2/

[Kevin Mitchell]

Man, if that's what it is thank you so much for your help! I didn't realize each lug had a specific order, kind of just assumed that as long as I was wiring it individually it would be fine. Fingers crossed it all works out when I get home and rewire it.

There has to be a common standard between devices otherwise signals get to the wrong places. I'm not sure if this is the problem with your build but sounds to be the likely scenario.

To do something successfully you must trial through doing it unsuccessfully. Otherwise what is there to learn? Blind luck is just that. At least the debug struggle can be entertaining just as it can be frustrating.

[jwyles90]

Totally! It's been frustrating for sure but I've also learned a ton in the process (and honestly it's probably been more informative than learning how to put the thing together). Fingers crossed the rewiring does the trick.

[jwyles90]

You were right! The wires were backwards so I put it all back together correctly and that did the trick (sort of).

I made a quick little video explaining what's up with it now. But it seems like when the pedal is engaged I can only get sound with the attack cranked all the way up, and even then it's like the pot has to be in just the right position for it to come through. On top of that there's this horrible squealing noise that's there, you can't hear it as much if I'm playing but the second j stop it takes over everything.

https://drive.google.com/file/d/10NdASeww6-g3KpWTWo4mzAdd-1fexbSM

My guess is that there's something wrong with the wiring on the attack pot somewhere?

[Kevin Mitchell]

Now would be a good time to use the audio probe to pinpoint where the squealing noise begins in the circuit. That junction would be the first to inspect for errors.

You could also review the transistor's pin voltages. This will draw out obvious issues. Well, obvious to those who understand circuits. Know your transistors pinouts. I also suggest doing the legwork yourself first. GGG has a page for these voltage. Anything that looks suspiciously off would need attention.
http://www.generalguitargadgets.com/pdf/ggg_tb_m2p_instruct.pdf

You can use this template to follow & share if needed.
Q1
E -
B -
C -

Q2
E -
B -
C -

Q3
E -
B -
C -

[jwyles90]

Thanks for the help! Turns out one of the resistors was the incorrect value. Which is weird, since it's the resistor that the instructions/bill of materials said to put in. But when I swapped it out for this random resistor that was included in the kit but not on the bill of materials it ended up working fine haha

[Kevin Mitchell]

That is weird because all of the resistors in your photos matches the board's BOM...
Happy you've got it sorted out!

[jwyles90]

Yea totally. I wouldn't have even thought about it but my friend noticed that the board in their example picture had a different looking resistor in one of the spots, and that happened to be the same value as a resistor that was just in the bag with everything else.