Help me understand popping

[stallik]

Great information from everyone which is really helping me but it prompts me to ask a (probably) silly question.
In cases where it's helpful to run a resistor between the input lug of a pedal and ground, is there any difference if the same resistor was inserted between signal and ground within the jack itself, and if not, would there be a detrimental effect if a patch lead made up in this way were to be used when there was no popping?

[Lbzg]

OK, I have seen some problems and I have some questions for you. I have copied your picture and have put some numbers onto it. The questions/problems are in the same order as the numbers on the picture.


OK, here goes:

1.  This 1µF capacitor should not be a polarised one. The schematic and the layout clearly say "NP" next to this cap. Either get a metal-film box cap or a special electrolytic that says "NP" on the case and with no grey stripe on the side.

2.  Same as 1. Replace this cap with one of the proper type.

3.  This cap is the wrong way round. The grey stripe should be "up" in this picture, not "down". This cap has probably been damaged internally. Take it out, throw it away and replace it with a new one. This might well be the source of your popping.

4.  These resistors are doing no good at all. You have 2 x 100k and 1 x 200 ohm, all in parallel. The total resistance will be just under 200 ohms. Take that whole assembly out because...

5.  ... this resistor is your output pull-down resistor. The value should only be 10k, not 100k, but we'll leave that for now.

6.  It is a little hard to tell what the value of this resistor is. The bands should be green/brown/black/orange/brown. There is only one way to be sure - de-solder one leg and measure it. If it is 510k, you can solder it back in. If not, replace it with one of the correct value.

7.  Same as 6.

8.  This resistor should be 100 ohms, not 470 ohms. Not a big issue, though. Leave it for now.

9.  This is your input pull-down resistor. I can not see the value. Could you tell me what the bands are? Anything above 1M will be fine. It is rare for a resistor to get cooked, but it is possible. I would replace it with a new one.

10.  This cap looks a bit small for 47nF. Please report the markings on this cap.

11.  Same with this cap. As I suggested earlier, you have soldered and re-soldered the input circuitry several times and your Input track has come off. This might also have "cooked" this cap. I would replace it with a new one.

OK, that's all I could see on the top picture. The picture of the solder-side is too blurred to see anything useful. Please could you take another picture that is more clear?

Also, what is that other board in the box? People often have huge problems putting 2 circuits into the same box, so I would like you to remove that other circuit completely so we can get this one working correctly. Once that is done, we can maybe look at putting that other circuit back into the box.

Cheers.

Thanks for cap I didn't know that NP or P caps are making difference in popping...I used one I had...ok I'll order NP.

On picture 10uF cap is wrong way but circuit was working (believe it or not). I have replaced it with 22uF and face it correct way but popping was still here...

Resistor are fine because I have build TS9 version and 510k are 511k so there are fine.

Vertical resistor is 1M but I have soldered another one on it and they are now 2M but popping is still present.

I have removed second PCB but popping is still here.

Also I have removed input and output resistors (that I have soldered on jacks) and that just give me popping on both on and off stage of pedal...but volume was on level with pedal volume (resistors seems to quite it down)...

Really don't know what is wrong with pedal...I will change for NP's but some people have build this pedal this way and they didn't report popping...don't know will try your way...I'm out of ideas...

[R O Tiree]

@ stallik It's probably negligible for most circuits but, if you put the resistor across the input jack tip->GND lugs, then you are going to have to run a GND wire from there pretty much parallel to the input wire. So, any charge in the Input cap has got to find its way off-board, past the 3PDT switch contacts and along the input wire and back to that resistor before it can escape to GND. Or (b) you put the resistor as close to the input cap as possible. Same for the output.

Of course, a lot of people use a neat switching system that grounds the input anyway when the pedal is disengaged, so putting the resistor across the input jack completely removes it from the circuit and it is now useless. The other aspect would be if you wired 10 pedals this way, with 1M resistors in each pedal, then, when all were bypassed, you would have an effective 100k sitting across your guitar - not good.

@Lbzg - Which way have you wired your 3PDT switch? Get hold of the Tonepad Offboard Wiring pdf file and wire it up as the last schematic "Offboard Wiring 5".

[Lbzg]

@Lbzg - Which way have you wired your 3PDT switch? Get hold of the Tonepad Offboard Wiring pdf file and wire it up as the last schematic "Offboard Wiring 5".

Yep, been tried that and now I'm using arons 2 in 1 box wiring...to be honest it is best for every pedal...simple and logical...

On tonepad offboard 5 I don't know why they put jumpers on switch...

I'm pretty sure that problem lays in some resistors or cap...do you think it can really be just switching layout? I will try again (maybe I did something wrong but then pedal would not be working but ok)...

And on your last post can you post some image on what do you think...just draw it simple as you can...

[stallik]

@mike Thanks for doing my thinking for me. Absolutely logical of course

[R O Tiree]

@Lbzg - The purpose of that weird switching arrangement is to short the PCB input cap to GND when in bypass mode, leaving the input jack directly connected to the output jack. This means that the input end of the cap is also connected to GND when the pedal is disengaged. As soon as you press the switch to engage the pedal then the cap disconnects from GND and connects to the input jack instead and the output from the PCB connects directly to the output jack. There is, therefore, very little time for a charge to build up and this minimises any chance of a pop. It is very neat and very clever and I have used it in every pedal I have built for years.

Next, we don't know if the charge is building up in the TS circuit or the other one in there. That is why I asked you to separate the 2 circuits. Once we have proved that the TS is working correctly, then we can do the same for that other circuit. Finally, we can look at putting them back together in the box. You see, there is a reason for me asking you these things - I am not doing it to be awkward. Remember a few posts ago when I said that we have to eliminate the causes one by one?

@stallik - No worries

[Lbzg]

No problem, I dont question your guides.  I have disconnected other pedal, I wrote it down few posts ago, maybe you didnt see it. :-) I have learned that resistor needs to be mounted on pcb not on jack. i will try all that and report back.

[R O Tiree]

OK. Try that other wiring scheme I suggested as well?

[Lbzg]

No good.

I did this:

I have put 2x 1M resistors on input between RB and input wire on PCB and 3x 1M resistors on output where they need to be on PCB and disconnected other pedal again and rewired switch to tonepad's layout.

Now I have 2 pops...pedal pops every time I press 3pdt...

Ideas?

[R O Tiree]

When this happens, is this the only pedal in your chain between guitar and amp?

The output pull-down resistor only needs to be 10k, not 3M.

Have you tried someone else's guitar? How about someone else's amp? How about both?

Have you tried input lead -> pedal -> amp and shorting out the tip and sleeve of the lead plugged into the pedal input jack?

If all else fails, maybe you can send it to me and I can find out exactly what is going on?

[Lbzg]

It is only pedal in chain.

Pulldown resistor on tonepad is 2.2m but I will give 10k a go.

My guitar is fine, as I said Distorsion plus from ggg is not popping...so guitar is fine...

I have shorted input lead and it pops...so problem is in pcb...:-(

Is there a pedal or any device that can suck popping or that extra voltage? i heard of some buffers...can they be build as diy? can someone post links?

[pinkjimiphoton]

in my experience, when i have any issues with popping, it's always related to the led.
what i found seems to work is a much larger anode resistor to limit current, maybe 47k or so and maybe a 10k from cathode to ground. seems to "float" the led and help.
don't know if it will help your problem tho.

have you tried pull down resistors to ground right on the switch itself?  wonder if that will help?

sometimes ya run into some conundrums when building things that can make ya crazy.

i'm thinking you got bad solder (no offense, but looking at the pics some of the joints look a little dicey to me) on a joint  to one of them ceramic caps, and it's acting like a transducer.
ceramic caps can get real microphonic in my experience. sometimes that's good, can give a nice "ring" to a tone, but sometime ya get mondo feedback or weird noises when ya hit the switch.

you CAN use polarized caps, if you have to, and they'll be fine as long as you orient them properly. always make sure the + side goes to the higher voltage and you'll be good.... like... if using as an input cap, there will be less voltage coming from your guitar than the transistor that follows, so put the negative side to the jack. sometimes it can be tricky.

remember too, you can make your own np caps by taking two larger caps, and tieing the cathodes together... say, if you want 1u, tie two 2.2u caps negatives together, and use the two positives  for your connections.

i think you may wanna replace them electros that were backwards. i agree, they are probably destroyed. they may pass signal, but if they're damaged, they will fail eventually.

i would also reflow any connections that look even remotely dodgy. use a solder sucker or a wick to get the old shit out of there, make sure you have a solid mechanical connection (cold solder joints too can cause pops and knocking, as they tend to be microphonic) between pad and component lead, and get some hot fresh solder in there.  make sure you heat the connection and not the solder!!

i've seen worse... hell, i've DONE worse.... but i'm betting that reflowing the board may help alieviate your problem.

if all else fails, try a different footswitch. i've had a few pedals come back from customers, and it's always the damn blue 3pdt's that fail. it's infrequent, but it does happen... out of the 150 switches i've ordered, i've had 4 fail so far which isn't too bad... but it does happen, especially if they get hot. all kindsa weird shit can happen.

good luck man..