Hi guys.
I've just finished my first proper build, a Thunderpuss. It fired up first time and does exactly what it says on the tin. Almost. I get a fantastic (and loud) clean boost but there's a buzz that is louder than the guitar signal even when playing. It's there when in bypass and gets louder as I turn the knob. I tested the circuit on my test rig before boxing it up and the buzz was present but I assumed that this may be a shielding issue as the circuit obviously wasn't yet in an enclosure. For a bit more info the enclosure it's in at the moment is just an old one that I had lying around that I screwed up the drilling on. It has more holes than necessary for the Thunderpuss so isn't 'sealed' like it would be once it's in it's proper enclosure (i'm still waiting for it to arrive). I've attached some photos in case anyone can see if I've done anything obviously wrong.
I've read the rules about asking for help and I've done what I can/know how to before posting here. i.e checked my wiring, soldering, put it on my test rig before boxing it up but as the pedal turns on and works I don't really know where to go from here. Is there a common mistake that is known to cause buzz?
Any help would be massively appreciated. It's such a confidence knock!
(http://img841.imageshack.us/img841/8844/20120621215423x.jpg)
(http://img32.imageshack.us/img32/3865/20120621215617x.jpg)
(http://img837.imageshack.us/img837/4594/20120621215108.jpg)
(http://img829.imageshack.us/img829/1375/20120621215148.jpg)
(http://img440.imageshack.us/img440/6111/20120621215355.jpg)
Thanks in advance.
It looks like you've explicitly grounded both of your 1/4" jacks, and unless they're insulated from the enclosure you don't need to do that. Just ground one of them and the other should ground through the enclosure to the grounded jack. By explicitly grounding both, you've created a ground loop that could introduce noise. I can't guarantee that that's what's causing your problem, but it's good advice anyway. Good luck!
(P.S. When testing a board with wired up jacks outside of an enclosure, you do need to explicitly ground both jacks.)
Thanks for the advice. The board is wired up using one of Gtr2's (very helpful) 3pdt boards. Like so: http://1776effects.com/wp-content/uploads/2012/01/3pdt_wiring.pdf
Please could I ask you to point out which wire I can get rid of to hopefully cure the grounding issue you mention. This is my first proper build and I'm still learning about grouning etc.
Thanks!
Could you describe the buzz a little bit better? Is it a constant hum, or is the effect itself
Buzzy? Does anything you do with your guitar affect the buzz?
Jacob
It's a constant buzz that doesn't fluctuate in volume/intensity and is audible above the guitar signal when I play. It gets louder the more I turn the knob up on the pedal. More effect=more buzz. It's only there when the pedal is in the chain i.e there's no buzz when I'm going direct to the amp. It's also there when the effct is in bypass.
What power supply are you using? Have you checked different cables and the power supply with a known-working pedal?
So the pedal itself is acting as an amplifier for the buzz. It definitely sounds like a grounding issue to me. Check and recheck your wiring. If you feel it could be a ground loop, taking the sleeve wire off of one of the jacks, doesn't matter which, may fix it. If that doesn't work, chances are you've made a mistake in your wiring somehow.
Jacob
Quote from: Guybrush on June 22, 2012, 03:02:20 PM
Please could I ask you to point out which wire I can get rid of to hopefully cure the grounding issue you mention. This is my first proper build and I'm still learning about grouning etc.
Desolder (or cut) one of the green wires you have going from an S pad on the 3PDT board to the sleeve lug on
one of your 1/4" jacks. Leave the other one in place.
I'd also reflow the joint on the ground lug on your power jack. Your effect is obviously grounded (because it works), but the graininess of that joint makes it look extremely suspect. Make sure you're getting enough heat to the tip of your iron and that you're not moving the wire during the reflow.
Quote from: mgwhit on June 22, 2012, 02:50:58 PM
It looks like you've explicitly grounded both of your 1/4" jacks, and unless they're insulated from the enclosure you don't need to do that. Just ground one of them and the other should ground through the enclosure to the grounded jack. By explicitly grounding both, you've created a ground loop that could introduce noise. I can't guarantee that that's what's causing your problem, but it's good advice anyway. Good luck!
(P.S. When testing a board with wired up jacks outside of an enclosure, you do need to explicitly ground both jacks.)
Hey mg, I don't think it is a ground loop issue, as all ground points go to the ground on the power jack. If I'm right, it's only a ground loop when you have two of those points (the ground on the power jack, I mean) connected to the same circuit. Please correct me if I'm wrong, but I wire all my pedals like that, with no hum issues.
Paul
Quote from: DutchMF on June 22, 2012, 04:37:08 PMHey mg, I don't think it is a ground loop issue, as all ground points go to the ground on the power jack. If I'm right, it's only a ground loop when you have two of those points (the ground on the power jack, I mean) connected to the same circuit. Please correct me if I'm wrong, but I wire all my pedals like that, with no hum issues.
Maybe. I'm just repeating info (that may be incorrect, or that I may have misunderstood) that I have heard in other guitar/pedal/amp forums. (Specifically, I've heard of guys having issues in Fender-style amps when they explicitly ground an input jack when it's already grounding to the chassis. Of course, I think the preferred solution there is to keep the explicit ground and isolate the jack from the chassis, but....) Like I said, I doubt that's really the cause of the buzz, but it's a simple thing to try.
Following up on what sgmezei said about the power supply, I'd also test with a 9V battery and see if that helps.
Thanks for the suggestions. I'll give them a try and report back. I really hope I can figure it out.
Damn near certain this is NOT your problem, but it makes it a wee bit tidier if you have the components flat on the floor, rather than with a few centimeters of leg between PCB and resistor/diode/cap.
At a guesstimate, I'd say the problem is the extraneous ground on the output (while everything is in the enclosure) as well. I'd say just rip it off, and if it makes no difference then re-attach it.
Looks like it might be a power supply issue. I plugged my Digitech Digitverb in and it also has a buzz but it disappears when I run it from a battery. Unfortunately I'm using Gtr2's 3pdt boards on my builds and they don't facilitate using a battery so I'm going to have to buy a new power supply. When I plug straight into the amp the buzz isn't present so I'm guessing its the power supply that I'm using for my pedals rather than the house electrics. I've been using a Diago power supply for years without issue but it looks like it might be time for a new one. Thanks for all the help.
You can use a battery with gtr2's 3pdt boards. As long as you have room in the enclosure. Just wire the battery ground to a switched input jack and the battery + to a switched power jack. See the standard wiring diagram. Check out my Snarkdoodle build from a few weeks back.
Its definitely a power supply issue. This circuit is extremely sensitive to different power supplies. You need a regulated, filtered 9 volt power supply to run this cleanly. I had the same problem. Also, mount your components flat on the board when possible and trim off the excess. Clean all the flux also, some flux is conductive and will cause static and other issues. You can wire a battery snap to a dc plug or buy one to rule out power supply issues.
example:http://www.ebay.com/itm/1x-9V-Battery-Snap-T-Type-cable-with-2-1-DC-Power-Plug-/180688377062?pt=US_Surveillance_Cables_Adapters_Connectors&hash=item2a11ddd4e6 (http://www.ebay.com/itm/1x-9V-Battery-Snap-T-Type-cable-with-2-1-DC-Power-Plug-/180688377062?pt=US_Surveillance_Cables_Adapters_Connectors&hash=item2a11ddd4e6)
If it works with a battery and not with your power supply then you know what the problem is.
Forgot to mention, this is a fantastic clean boost when working properly. I also had a power supply problem with the Pork Barrel chorus, another great sounding pedal!
Quote from: mgwhit on June 23, 2012, 06:23:58 PM
You can use a battery with gtr2's 3pdt boards. As long as you have room in the enclosure. Just wire the battery ground to a switched input jack and the battery + to a switched power jack. See the standard wiring diagram. Check out my Snarkdoodle build from a few weeks back.
Thanks mgwhit. I'm struggling to see on your Snarkdoodle photo's as to just where the battery snap leads are connected. I'm still at the 'following the layout diagram' level of building and I'm not really sure what you mean in terms of switched jacks. I don't suppose you could add the battery snap to this diagram could you so I can see what you mean?
(http://img641.imageshack.us/img641/5913/3pdtboard.jpg)
Edit: I've checked the standard wiring diagram and can see that I need a TRS jack for the battery ground and the battery + just goes to the spare lug on the DC jack.
And thanks for the link ncdb07. I'll try those out too.
As a temporary measure, you can add extra caps for power supply filtering. A 470uF and 100n in parallel between + and - might do the trick.