Hey all,
I'm working on a Green Bean tubescreamer build. Everything is put together. When I am playing in bypass the signal is clean and great, but when I engage the pedal the signal dies and is replaced with a constant "popping" sound. Since I'm no good at describing that sound I've uploaded a video so you can hear it yourself.
https://www.youtube.com/watch?v=aeKtfN8iARQ&list=UUcyDx1jstUevNmJUeVzBe9Q
Anybody know how I can fix this? So far, none of the pedals I've built are working, but all of the continuity checks out, etc. I'm getting really frustrated and desperate. Thanks!
If the switch wiring is okay (you say continuity checks out okay, so i'll assume it is for now) post the voltage readings.
And a picture of the board, top and bottom
Are you using a wall DC plug?
I have heard that noise when I have had a bridge on the 9+ side to ground and the one-spot protection is kicking in and turning it off and on making that popping noise. Just a thought.
Cody
I am using a OneSpot wall wart. I'll double check that area when I get home from work today, as well as try to take some helpful photos of the board. Thank you.
Quote from: selfdestroyer on September 22, 2014, 06:53:32 AM
Are you using a wall DC plug?
I have heard that noise when I have had a bridge on the 9+ side to ground and the one-spot protection is kicking in and turning it off and on making that popping noise. Just a thought.
Cody
Yep, I'd go with this.
I checked for a solder bridge between 9+ and Ground but didn't find one.
Here are some pics as promised. Much like the build in the PDF instructions, I, too had some things happen.
Component side:
(http://i.imgur.com/Mjv1Z6b.png)
Reverse (I didn't have PCB mount pots so I wired them in):
(http://i.imgur.com/i0mb6WN.png)
Full wiring shot:
(http://i.imgur.com/PUd6u7f.png)
Thanks again, guys!
Is it just me, or do you have your power connected directly to the top left lug of your 3PDT? If you do, that is shorting straight to ground every time you activate the effect.
You also don't need to ground both 1/4" jack sleeves -- you've created a ground loop (which is the least of your worries right now ;) ). Check out the standard wiring diagram for reference:
http://www.madbeanpedals.com/tutorials/downloads/StandardWiring_MBP.pdf
I was using this offboard wiring:
(http://1.bp.blogspot.com/-k5Sh68yVU18/TzGRFKbiALI/AAAAAAAAAlk/CbfaaduUjYQ/s1600/!Offboard+wiring.png)
When I had first put together the pedal using the MadBean standard wiring it didn't make sound in bypass or when engaged and it also had a really loud and nasty hum to it. I'll remove the connection from DC to footswitch and see if that helps.
The wiring diagram you posted shows power going to the switch through a current-limiting resistor and an LED. I can't see if you've included those in your build. If you have, my apologies, but it looks like a straight green wire from your DC jack to the switch to me.
The switch sleeve grounding in that diagram would be fine if you were using insulated jacks (or if you hadn't mounted your jacks into an aluminum enclosure yet). Like I said, the ground loop isn't causing your problem, but you should fix it at some point.
That wiring diagram is just fine. With or without the ground wire connected to the output jack it should be fine because the output jack is being grounded by the enclosure. My concern is your wiring. Those long exposed wires can be bumping into other pads, the enclosure, the potentiometers, etc.... You should try to have your wires pushed in one side of the board as far as possible and solder form the other side. The LED setup is fine also, no need to remove it. It just looked from your picture that the switch was hooked directly to the +9V of the DC Jack.
Are you using Lead free solder? It looks like you may have some cold solder joints. A good iron, 60/40 solder, and some practice should clean this up for you and help eliminate some problems.
I'm using leaded flux core solder and a Weller 25watt iron. I'll try to go through and reflow all of the solder, as well as push those wires in more so no metal is exposed. It seems like it heats 18 & 22 gauge wires up with no problem, but it takes forever to get the component leads to heat up for the solder.
I feel like I missed something. Is there an LED and a CLR between your power jack and your 3PDT footswitch?
I think you have your 9V and GND connections reversed on your DC jack. The GNDs should go to the lug that looks like a small "L" on the DC jack. The 9V goes to the outermost smaller straight lug.
Your input jack SLEEVE is goin to the same spot that your PCBs 9V wire is going to! I'm surprised you are getting a good clean signal when bypassed and power connected! You are shorting power to ground as soon as you plug in your cable and the 1Spot
Quote from: Govmnt_Lacky on September 23, 2014, 10:23:48 PM
I think you have your 9V and GND connections reversed on your DC jack. The GNDs should go to the lug that looks like a small "L" on the DC jack. The 9V goes to the outermost smaller straight lug.
Your input jack SLEEVE is goin to the same spot that your PCBs 9V wire is going to! I'm surprised you are getting a good clean signal when bypassed and power connected! You are shorting power to ground as soon as you plug in your cable and the 1Spot
I think he has that right, it's just hard to tell with all of the same color wiring
Quote from: mgwhit on September 23, 2014, 10:11:03 PM
I feel like I missed something. Is there an LED and a CLR between your power jack and your 3PDT footswitch?
I think there is we just can't see it in the picture.
Ok well a quick check for a short would be to measure resistance between the 2 poles used on the DC jack. If you see something less than ~200 ohms then you have a problem. If not then you need to post voltages on the IC legs and the transistor legs
Also, as said before, get rid of the yellow wire from the output jack sleeve to the stomp switch. Ground loop there.
This won't fix your problem, but you should invest in a Weller WLC 100 ($40). It should improve your soldering quality 10 fold.
We have lift off. Thank you so much. Your wisdom is invaluable and I appreciate it so much. After it's all boxed up I'll post a video. I believe the culprit was either a cold joint or the tiniest of solder bridges that I found. I'm so excited. Y'all helped me finish my first build!
Thanks everyone for pitching in to solve the problem. I don;t say that enough.
As promised, the final build
I wish I could crank it right now but my roommate is gearing down for the night. Thanks again, forum gurus.
Glad you got it going.. now get going on your next build :]
Cody
Quote from: nineknives on September 24, 2014, 02:29:19 AM
We have lift off. Thank you so much. Your wisdom is invaluable and I appreciate it so much. After it's all boxed up I'll post a video. I believe the culprit was either a cold joint or the tiniest of solder bridges that I found. I'm so excited. Y'all helped me finish my first build!
Congrats! :) :) :)
Did you end up replacing R1 again -OR- was the resistor in the second picture left on the PCB?
Congrats on getting it working ;)
Lacky, I didn't have to replace anything on the board. I got rid of the ground loop and reflowed some solder in places.
Quote from: nineknives on September 24, 2014, 01:50:00 PM
Lucky, I didn't have to replace anything on the board. I got rid of the ground loop and reflowed some solder in places.
Cool.
Still.. I wonder what that resistor value was ???