Chuck D. Bones
Circuit Wizard
Yes. A drawing would be better, but I think you have it right. The buffer has to be after the Echoes switch.
Tearjerker
- Thread starter Big Monk
- Start date
Big Monk
Well-known member
Thank you for bringing it up. I believe I was going to go right into the buffer off of the output wire.
Big Monk
Well-known member
I had time tonight to throw together a simple 2N5457 buffer circuit:
I tested it out and it passed signal so it’s a success!
I used the circuit from the AMZ Wah Buffer blog post:
I used 2.2M from Gate to ground and Gate to Power, 10k from Source to ground, 0.1 uf on the input and 10 uf on the output.
I tested it out and it passed signal so it’s a success!
I used the circuit from the AMZ Wah Buffer blog post:
I used 2.2M from Gate to ground and Gate to Power, 10k from Source to ground, 0.1 uf on the input and 10 uf on the output.
Chuck D. Bones
Circuit Wizard
Ahhh, the "lumpy cable." Would it surprise you to know that there are satellites flying with lumpy cables?
You need an anti-pop resistor after the 10uF cap because it goes to a switch in your circuit. You also need an anti-pop resistor before the 100nF cap since it also goes to a switch.
Biasing the gate to 1/2 Vcc is not the magic number, but it's close enough. FYI, the same buffer could be realized with a MOSFET.
You need an anti-pop resistor after the 10uF cap because it goes to a switch in your circuit. You also need an anti-pop resistor before the 100nF cap since it also goes to a switch.
Biasing the gate to 1/2 Vcc is not the magic number, but it's close enough. FYI, the same buffer could be realized with a MOSFET.
Big Monk
Well-known member
Since I still have long leads, I can patch in those pull down resistors easily. I also need to extend the power lead to reach down to the DC jack.
Harry Klippton
Well-known member
Don't let Derek roll the blunt I guess 
Big Monk
Well-known member
Here is Lumpy Rev. 0002:
I added the pulldown resistors on input and output and extended the power lead so i can run it discreetly down the side to the DC Jack.
A few minor concerns after hooking it up onto the Protoboard:
1.) It's slightly less than unity gain but the Volume trimpot will help there
2.) There's a fair amount of hum and noise when engaged on the Protoboard. I know that noise is to be expected when something is outside and enclosure so I am going to wire it up into the pedal and see how it goes. If by chance the noise carries over, I'll make another attempt for Lumpy Rev. 0003 and patch it in.
3.) Between bypass and enagged on the Protoboard, I'm losing some high end. I imagine the 10 uf I used on the output may be contributing. Again, I'll see how it works out and since it's modular, I can always build another and tweak it based on what i hear in the circuit.
I added the pulldown resistors on input and output and extended the power lead so i can run it discreetly down the side to the DC Jack.
A few minor concerns after hooking it up onto the Protoboard:
1.) It's slightly less than unity gain but the Volume trimpot will help there
2.) There's a fair amount of hum and noise when engaged on the Protoboard. I know that noise is to be expected when something is outside and enclosure so I am going to wire it up into the pedal and see how it goes. If by chance the noise carries over, I'll make another attempt for Lumpy Rev. 0003 and patch it in.
3.) Between bypass and enagged on the Protoboard, I'm losing some high end. I imagine the 10 uf I used on the output may be contributing. Again, I'll see how it works out and since it's modular, I can always build another and tweak it based on what i hear in the circuit.
Big Monk
Well-known member
So, some good news and weird news.
Good news, I’ve got the “Echoes” and Bypass Switch wired up. I put a switch mounted 50k trim for Volume adjustments on the “Echoes” mod and the black wire on the switch is just temporarily hooked up until the JFET Buffer board gets here:
Weird news is I have everything hooked up temporarily for testing before the buffer goes in and I’m not getting signal through in On or in Bypass.
So I tried the obvious:
1.) Ran continuity checks on the bypass signal path and it was OK.
2.) I can tell signal is passing through when ON because I can hear the frequency sweep of the Wah as a whooshing sound.
3.) So I thought it might be a bad stomp switch. I removed the I/O jack connections and tied them together. Nothing.
I can’t quite figure it out. When ON, signal is going through the Wah because I can hear the sweep. It can’t be the switch because it’s switching the LED and tying I/O together with the wires yields no bypass tone.
Good news, I’ve got the “Echoes” and Bypass Switch wired up. I put a switch mounted 50k trim for Volume adjustments on the “Echoes” mod and the black wire on the switch is just temporarily hooked up until the JFET Buffer board gets here:
Weird news is I have everything hooked up temporarily for testing before the buffer goes in and I’m not getting signal through in On or in Bypass.
So I tried the obvious:
1.) Ran continuity checks on the bypass signal path and it was OK.
2.) I can tell signal is passing through when ON because I can hear the frequency sweep of the Wah as a whooshing sound.
3.) So I thought it might be a bad stomp switch. I removed the I/O jack connections and tied them together. Nothing.
I can’t quite figure it out. When ON, signal is going through the Wah because I can hear the sweep. It can’t be the switch because it’s switching the LED and tying I/O together with the wires yields no bypass tone.
Harry Klippton
Well-known member
Uh oh am I gonna have to rescind my previous statement? 
Big Monk
Well-known member
Uh oh am I gonna have to rescind my previous statement?
I can't quite figure it out.
No bypass led me to believe it might be a bad stomp switch but directly connecting the jacks together, and not getting bypass tone, squashed that.
Then I thought maybe I disturbed the board somehow but audio probed and found nothing. Also, you can hear the sweep acting on the whooshing white noise when the circuit is engaged.
What it might be is the connection on the pulled pad. I wonder if I scraped away too much of the mask and am grounding out the input.
@PedalPCB Is everything sans solder pads and traces a ground plane on these boards?
Big Monk
Well-known member
Got it!
I was correct about the input wire. When I scraped the mask back I must have exposed the ground plane and soldered the wire to it. I’ll just need a discrete 24 gauge black solid core jumper over to the jack and it should be good.
Everything is pretty much done and I can zip tie some wires and put in the buffer when it gets here.
I was correct about the input wire. When I scraped the mask back I must have exposed the ground plane and soldered the wire to it. I’ll just need a discrete 24 gauge black solid core jumper over to the jack and it should be good.
Everything is pretty much done and I can zip tie some wires and put in the buffer when it gets here.
Big Monk
Well-known member
Sure. I didn’t have the generic board material so the PedalPCB was cheaper and, in my hands at least, will look cleaner.
Which is what I have to do now anyway! I’ll get it squared away. Some discreet black Sharpie over the exposed trace and a very thin black jumper riding around the jack.
Big Monk
Well-known member
Well, that did the trick! I was simply grounding out the input. Wah works fine and “Echoes” mod is operational.
Not much left on this. When the buffer PCB gets here I’ll make the terminations and get that sucker in there!
Once that’s finished I’ll just bunch together and zip tie the switch wires and it’ll be good to go.
The last bit will be one aesthetic and one functional consideration: an E.W.S. bottom plate and a name badge for the front.
Not much left on this. When the buffer PCB gets here I’ll make the terminations and get that sucker in there!
Once that’s finished I’ll just bunch together and zip tie the switch wires and it’ll be good to go.
The last bit will be one aesthetic and one functional consideration: an E.W.S. bottom plate and a name badge for the front.
Big Monk
Well-known member
Alright folks, for those of you who have tuned into this run on sentence of a build thread, she’s all set.
JFET Buffers came in today and I installed and tested it. Worked like gang busters and has a real small footprint which is nice.
I think the wiring came out nice and it is pretty close to how I pictured it in my head:
JFET Buffers came in today and I installed and tested it. Worked like gang busters and has a real small footprint which is nice.
I think the wiring came out nice and it is pretty close to how I pictured it in my head:
Big Monk
Well-known member
Bumping this because I rewired my wah today and while the wah works fantastic, my Echoes switch is not behaving exactly as I want it.
I get the oscillation but am not getting the stuttery, whooping oscillation when moving the wah treadle back to a specific point.
Paging @Chuck D. Bones
I get the oscillation but am not getting the stuttery, whooping oscillation when moving the wah treadle back to a specific point.
Paging @Chuck D. Bones
Chuck D. Bones
Circuit Wizard
Which guitar are you using? Pickups, guitar volume, guitar tone and wah treadle position all interact. It's tricky to find the the settings that cause warble.
Big Monk
Well-known member
I had to resolder a few wires on the Echoes switch breakout board and then the warble popped up.
Using my Black Strat type guitar, it popped out with Bridge tone up, selector in the Neck/Middle position and tweaking the treadle and neck/middle tone control.
Have to try again with my Les Paul.
