Mudbunny: Putting the mid pot on a switch?

[henryadams]

Hey, Beaners:

So I've built a few pedals, always from someone else's PCB, and I've done a little bit or circuit bending myself, though I'm definitely a noob.

So, here's what I'd like to do:
1)I want to build the Mudbunny to the civil war specs (easy enough).
2) I want to put in the extra mid pot (again, got that covered).
3) I want to have the ability to go from stock Mudbunny to Mudbunny with mid pot engaged by stomping on a switch. This way, i can be playing the stock Mud for rhythm, then when I need to cut through the mix more, I can just kick the switch. This is where my questions begin:
       A) What sort of switch do I need? A dpdt stomper? An spst? I've been looking at Small bear, and they have a bewlidering number of switches.
       B) How would I wire it so that the pot is on the switch?
       C) Is there a way I could rig an LED onto the switch as well, so that when the mid pot is engaged, I've got a visual confirmation?


If I'm overthinking this, or making it more complicated than it needs to be, please let me know.

[k.rock!]

Ok, I think this is what you might need to do...



On the left is the schematic of what I think you're trying to do. Switch between a fixed resistor and a potentiometer. As you can see you'll need 2 poles for that and if you want an LED you'll need a third pole.  So essentially, you need a 3PDT if you want the LED and a DPDT if you just want to switch between the two...

I just drew this real quick so if I messed up, and somebody can correct me that would cool too

Thank! Hope that helps

-Kaleb

[henryadams]

Hey, Kaleb, thanks so much, and I'm pretty sure it is making sense to my noobish brain.

Just one quick clarifying q: on the build instructions for the MB, it says that if you want to omit the mids pot, you just jumper pads 1 and 3 on the mids part of the pcb. So, wouldn't that mean that instead of attaching a resistor to lugs 1 and 2 of the 3pdt, you'd just jumper them? Also, the "leads to board" go to pads 1 and 3 on the mids part of the pcb? And last question (I promise), when I wire the pot to the switch, I'd wire one of the outer lugs and the middle one, right?

[jkokura]

What you do when you jumper 1 and 3 is send everything to ground. That pin 1 on the board is connected to ground.

What you would want to do when you wire up that pot is connect lug 1 to one of the sleeve lugs of your jacks OR you can still connect it to the PCB lug 1 spot.

Great answer Kaleb, you're really coming along on the whole understanding things around here!

On a completely different note, it's really, really great to see how many people hang out here on a regular basis and are stepping up to offer tech help and answer questions. Thanks so much to everyone!

Jacob

[k.rock!]

What you do when you jumper 1 and 3 is send everything to ground. That pin 1 on the board is connected to ground.

What you would want to do when you wire up that pot is connect lug 1 to one of the sleeve lugs of your jacks OR you can still connect it to the PCB lug 1 spot.

Great answer Kaleb, you're really coming along on the whole understanding things around here!

On a completely different note, it's really, really great to see how many people hang out here on a regular basis and are stepping up to offer tech help and answer questions. Thanks so much to everyone!

Jacob

Thanks Jacob! I'm really learning a lot here!

Let us know how it worked out for you Henry


-Kaleb

[bigmufffuzzwizz]

Thats a great idea and yes so simple to do. Nice little drawing kaleb. Makes it so easy to understand!
The way you drew it has an LED indicator too correct? What I was thinking was to simply connect the pot to the bottom row of a 3pdt and the middle lugs to the presence pot pads on the board. But I see you'd have to jumper the wiper the to an outside lug and just use 2 lugs.
Great mod idea!

[henryadams]

Ok, so I got this baby all wired up, and it sounds great (I'll post pics over in the build forum). The switch for the mid pot should be wired like this

        1     2     3
A      __  __   __

B     __   __   __

C    __    __   __

jumper 1A and 2A together

1B and 2B go to pads 1 and 3 on the mid pot part of the board

3B goes to LED

1C and 2C go to the 1 and 3 terminal on the pot

3C goes to ground.


The only issue I have is that when I switch on the mid pot, there is a very loud pop. Any ideas on how to get rid of this?

And Kaleb, thanks for the help!

[jkokura]

You're pretty close with the LED.

Usually good practice is to attach the ground to 3B rather than C. Then you can connect an LED to 3A and another to 3C so that you can have an LED for each setting. This might also remove the pop.

Also, I'm pretty sure you need to be wiring lug's 3 and 2, but I haven't verified that with the schematic...

Jacob

[k.rock!]

You're pretty close with the LED.

Usually good practice is to attach the ground to 3B rather than C. Then you can connect an LED to 3A and another to 3C so that you can have an LED for each setting. This might also remove the pop.

Also, I'm pretty sure you need to be wiring lug's 3 and 2, but I haven't verified that with the schematic...

Jacob

Good catch Jacob! I drew the ground in the wrong place...I usually put it in the middle tab as well. The way I like to think about it is kinda like "I'm bringing the negative LED lead TOWARD ground"...the way I drew it, I was "bringing the GROUND towards the LED"...So yeah, This might help your pop go away.

Glad to help! And thanks again Jacob

-Kaleb

[henryadams]

You're pretty close with the LED.

Usually good practice is to attach the ground to 3B rather than C. Then you can connect an LED to 3A and another to 3C so that you can have an LED for each setting. This might also remove the pop.

Also, I'm pretty sure you need to be wiring lug's 3 and 2, but I haven't verified that with the schematic...

Jacob

Hey, Jacob, thanks alot. I'll try out the new LED wiring and report back.

So here's what I'm thinking on wiring the pot (and bear with me. I'm a history guy, not a an analytical/engineering type).

On the build instructions for the MB, it says if you want to build a regular 3 knob pedal and forgo the mid pot. you jumper pads 1 and 3 on the board. Pad 2 (AFAIK) and lug 2 on the pot is for the wiper, right? So what I did is this: I connected lug 2 of the pot to pad 2 on the board, leaving lugs 1 and 3 wired to the switch. It kinda made sense to me, in a dim way, that when bypassed, 1 and 3 would be jumpered, and when engaged, 1 and 3 would lead to the pot, which is already wired to pad 2 on the board. Does that make sense? In any case, I can hear the pot working (though it's pretty subtle).

Thanks again, all of you for the help.

[henryadams]

You're pretty close with the LED.

Usually good practice is to attach the ground to 3B rather than C. Then you can connect an LED to 3A and another to 3C so that you can have an LED for each setting. This might also remove the pop.

Also, I'm pretty sure you need to be wiring lug's 3 and 2, but I haven't verified that with the schematic...

Jacob

Hmmm, rewired it, and it certainly made the pop go away from the mid switch, but now the effect on/off switch pops REALLY loudly...Any ideas, or should I just switch it back to my original wiring?

[k.rock!]

You have a "floating" ground problem most likely. I don't know exactly how you have your pedal wired, but the rule is that you should have every ground tied together to a common place (it's a common ground). So, I think you may have at least two different paths to ground that may cause your loud pop. Think of it kinda like a daisy chain of grounds or a "star" approach where everything is connected to a single point ground (like the ground tab on the DC jack).

Make sure you have board ground, negative lead on battery, sleeve of input jack, main switch, mids switch and power jack ground tied together to ground. Also, try grounding your output sleeve as well. You can just put a wire between input and output sleeves.

Let us know if that helps


-Kaleb

[henryadams]

You have a "floating" ground problem most likely. I don't know exactly how you have your pedal wired, but the rule is that you should have every ground tied together to a common place (it's a common ground). So, I think you may have at least two different paths to ground that may cause your loud pop. Think of it kinda like a daisy chain of grounds or a "star" approach where everything is connected to a single point ground (like the ground tab on the DC jack).

Make sure you have board ground, negative lead on battery, sleeve of input jack, main switch, mids switch and power jack ground tied together to ground. Also, try grounding your output sleeve as well. You can just put a wire between input and output sleeves.

Let us know if that helps

Hey, Kaleb:

Thanks so much. That was a really clear, easy description for a guy who needs it. I'll try it and post back.


-Kaleb

[k.rock!]

haha I kept looking for your response here and it seems it got inserted within the quote...

No problem dude! Give it a shot and let me know how it works out for ya


-Kaleb

[henryadams]

Hmmmmm. Now I'm stumped. I've grounded the output jack to the input, and moved the wire grounding the PCB from the switch to the output jack. Everything's going to the output jack (I have no battery clip. I power all my pedals with a 1 spot, so I just leave it out).

Might I need to connect the grounds on the 2 switches together?