Wah "Pops" When Engaged

[PlayItAll]

Hello all,

Anything I can do to get rid of the annoying "pop" when I turn on my Dunlop wah? It is a new model 535Q.

Thanks!!
Ed

[greg]

Hello,

Take a look at the Tech Tips link found at www.geofex.com. You'll see info on the POP situation and the fix (along with a wealth of other great info).

Good luck,
Greg

[tgeucihtnairk]

Hello,

I'm new to this forum and I've got the same problem with my Jim Dunlop Cry Baby Wah.
I've read the Tech Tips but I don't quite get what I've got to do. English isn't my mother tongue so please pardon me if it seems obvious to you.

Thanks for your replies
Carsten

EDIT: Maybe I should tell you what exactly I don't understand.

"For mechanical switches, put a 100K to 4.7M (exact value does not matter) resistor from the "outboard" end of both the input and output capacitors to ground."

What exactly is meant with ""outboard" end of the input" and how can I solder it "to ground"?
Can anybody post of a picture of that?

[cjlectronics]

Something I never really understood about adding a resistor to squash the pop is why do this if from the factory the switch didn't pop so adding a resistor is not fixing the source of the problem. In my experience, dirty contacts in the switch or leaky capacitors fix this problem most of the time.

What am I missing here?

CJ

[Bloodbath]

Originally Posted by cjlectronics

Something I never really understood about adding a resistor to squash the pop is why do this if from the factory the switch didn't pop so adding a resistor is not fixing the source of the problem. In my experience, dirty contacts in the switch or leaky capacitors fix this problem most of the time.

What am I missing here?

CJ

Maybe because when the pedal wasn't true bypass you weren't switching the whole circuit in and out of the chain.

I believe in PlayItAll's situation he either has a bad switch or a component (probably a cap) is going bad since the 535q isn't true bypass.

This could also be the problem with tgeucihtnairk's pedal. I don't know if tgeucihtnairk has true bypassed the pedal or not.

[tgeucihtnairk]

I didn't true-bypass it. But I bought it used on ebay a few weeks ago. Maybe the owner before me did that.
How can I post a picture here? I could show you what it looks like.

[Bloodbath]

Originally Posted by tgeucihtnairk

I didn't true-bypass it. But I bought it used on ebay a few weeks ago. Maybe the owner before me did that.
How can I post a picture here? I could show you what it looks like.

There is an insert image button when I reply to a thread or you can upload an image to something like Photobucket and use the IMG tags.

There's no need to though. If your switch has 3 lugs on it, it isn't true bypass. If it has 6 or 9 lugs on it, it is true bypass.

[tgeucihtnairk]

Ok, it only has 3 lugs. So, no true-bypass here

[Bloodbath]

I'm going to go with either your switch is bad or you have a bad component.

Start with the caps as they are cheaper than the switch to replace.

If that doesn't work, now might be a good time to true bypass it and possibly add an on/off LED if you want one.

I have a ton of working original 3 lug switches pulled out wahs if you simply just want to replace your original one or I can help true bypass it if you want. PM me if you are interested.

[antiunderscores]

Originally Posted by tgeucihtnairk

Hello,

What exactly is meant with ""outboard" end of the input" and how can I solder it "to ground"?

I don't think anyone actually answered this question yet, so i will try to. It is talking about the input and output capacitors, and when it says the "out board end" I think it is talking about the 'legs' of the capacitor which are towards the outside of the pedal. So for the output capacitor you should solder the end that is closer to output, and the leg of the input capacitor the leg closest to the input, hope that makes sense.

And it is saying to solder a resistor to these sides of the capacitor and solder the other end of the resistor to ground. Im not sure how to explain what ground is, the neutral, earth (or "earthing" something), etc. If you look at the schematic of your pedal I'm sure you can find a nearby point to that has a path to ground. I'm trusting you have at least a small amount of electrical experience.

hope that helped and my facts were right, can someone confirm what I've said?

[Bloodbath]

Not exactly. What you want to do is put something like a 1M resistor from the input tip to ground.

I'm not sure why they would use the term outboard. I'm pretty sure they mean that if you were looking at a schematic of the pedal that you would put the resistor towards the leg of the capacitor at the beginning (outer) of the circuit.

I would just put a 1M resistor on the input tip to ground. That should be sufficient and I would only do this if you have true bypassed the pedal. If you didn't true bypass the pedal, there is probably something else wrong with your pedal.

[Robert M. Martinelli]

Originally Posted by cjlectronics

Something I never really understood about adding a resistor to squash the pop is why do this if from the factory the switch didn't pop so adding a resistor is not fixing the source of the problem. In my experience, dirty contacts in the switch or leaky capacitors fix this problem most of the time.

What am I missing here?

CJ

Hi CJ,
Actually, without that resistor the wah pops just as well, maybe in a less audible manner....Obviously the problem can get worse with the switch getting dirty/old. This explains why cleaning the contacts seems to sometime cure the issue ( but the problem is likely to happen again later ).

The problem actually comes from the foot-switch being an electro-mechanical device, its operation is not seamless, because it takes some hundredths of a second to switch between positions. while this happens, the circuit is "open", then it closes again when the switch comes to the opposite position, thus generating a "pop". The resistor keeps the circuit ( very slightly indeed, but that's enough to fix the "popping" ) loaded, so that the switch operation becomes "silent".

I have built myself several wah pedals, I use a 1 MOhm Metal Oxide resistor ( I use M.O. resistors in all my builds ) connected between the input jack and GND, and it has always done the job just fine.

Hope this clarifies the matter in a sufficiently clear manner ( I think I still have a long way to go to master my English ).

Best regards

Bob

[tgeucihtnairk]

Ok, I don't really get this hahahaha
Maybe my english just isn't enough for that.
I'll trying going with these explanations for true-bypassing it, adding a LED and killing the "pop"
I'll let you know if it worked for me. It's 10am here now so i can go to buy all the stuff I need