Popping sound when pedal is engaged

[Lino22]

I thought in a small signal area we want a small output impedance seeing a large input impedance. When the frequencies get high, the energy moves outside the conductor and is transported by an EM wave along the conductor, then i understand matching is necessary to prevent the signal to be reflected and destroy something that is not designed to see large signals.

[Baran Ismen]

So, did anyone watch the video and have some idea about what's going on?

[antonis]

So, did anyone watch the video and have some idea about what's going on?

What's going on is located on country of origin..

[Baran Ismen]

So, did anyone watch the video and have some idea about what's going on?

What's going on is located on country of origin..

You should be well aware of how f.ced up our economy is and the skyrocketing inflation here, komşu. This was the best I could afford for a reverb pedal :/ I dislike Chinese scraps as much as most people do -just because of this very stupid example here- but...

[Baran Ismen]

Most likely yes. One thing in addition (I suppose) is that probably the input of the circuit is also grounded on bypass. Because when I engage the pedal, effect "starts" from the scratch, and there's around 10-15ms of delay. I mean, I could not find another answer to explain this.

I don't think it happens because of the input being grounded. Is it grounded? Can you please measure it?

When I short the middle and top-middle legs of the switch, this is no longer a case, no delay, working like a charm, no delay, decay goes on, but LED stays on permanently.

Sure when you connect them you will connect the LED minus to the ground permanently.

Try to find out what is connected to the top middle lug and the top right one. This is an unusual way of connecting 3PDT, and those two unused lugs may have a reason which is not apparent.

I have Just found out that on bypass, input and output tips are grounded.

[Lino22]

Well done - i suppose you mean the tips where the pulldowns are soldered. Then the pulldown resistors are of no use any more. The problem must be elsewhere.

[Lino22]

Actually, you have experienced what i have experienced not that long ago. Right after i have connected DC to a pedal, i can measure a massive DC voltage on the outer side of the output cap. This voltage will slowly diminish through the volume pot, but before that, it causes a loud pop when i turn the pedal on. After that there are no audible pops at room volume levels. But this doesn't bother me as in real life, i never play right after i have connected a pedal in.
There are always pops in full blast amp levels. Always - my humble pedals or factory made, mass-produced pedals.

[Baran Ismen]

Well done - i suppose you mean the tips where the pulldowns are soldered. Then the pulldown resistors are of no use any more. The problem must be elsewhere.

They are useful, but actually decreases the time that the pop disappears drastically. However, as you mentioned Before, i tried the current modification in my pedal board tonight (i was trying it individually) and noticed a slight gain/tone loss, even though i changed these resistors to 22k (bigger than this actually doesnt help at all). Crap! I have some buffered pedals at the beginning, in the middle and at the end, but i actually did not connect the one in the end (boss rc 2),maybe it would compensate, as i know its also buffered.

I actually noticed something that, there are 6 or 7 polarized caps all around the circuit and all of them are 100uf/16v. Its possible indeed, or a coincidence, but i have seen tons of layouts so far yet none of them had this much "same" valued caps. I somehow thought that, would these chinese guys go cheap and put all the polarized caps as the same. Because this dc voltage issue on output and popping due to dc offset are seem to somehow related with capacitors.

Or maybe i am overstating...

[Lino22]

I am not sure i u understand. If the unput and output are grounded, how would pulldowns make it any better?

[bluelagoon]

I am not sure i u understand. If the unput and output are grounded, how would pulldowns make it any better?

My understanding is, they are not grounded until after switched to bypass, where its needed the pulldowns to take the DC offset voltage to ground at the point of switching, before the in and out become grounded. 

[antonis]

My understanding is, they are not grounded until after switched to bypass

That's for sure or we'll have a dead silent pedal..

where its needed the pulldowns to take the DC offset voltage to ground at the point of switching, before the in and out become grounded.

What DC offset..??

[bluelagoon]

isnt it the DC leakage through the in and out caps called DC offset, at least i thought so, stand corrected otherwise, may well have got my wires crossed. But it is the unwanted DC going through those blocking caps that causes the popping, which is the reason for the pulldown resistors, right ? ?
Whatever that DC leakage is called ??
Sorry Antony, I'm only a novice hack wanna be. But learning every day

[Lino22]

I have a question, i realized i don't get two things:

I am turning the TB pedal on - no grounding input or output or pull-downs, just a plain poppy TB
1. How come the DC charge leaked through the output cap causes a pop - it is DC so how come it gets through the input cap of the thingy behind it be it another pedal or an amp.
2. What happens to the DC charge that leaked through the input cap - is it gonna spread to the input cable and stay around till the pedal is turned off and then it discharges?

[antonis]

Not again..!!!
(lost post..)

@bluelagoon: IN-OUT pull-down resistors (generally called "bleeders") often met there for caps discharge when effect is OFF..

IMHO, there is no need for such resistors as far as IN-OUT are grounded in by-pass mode..
(unless we deal with a veeeeeeery slow trasition time switch in conjunction with a veeeeeery leaky cap..)

[antonis]

1. How come the DC charge leaked through the output cap causes a pop - it is DC so how come it gets through the input cap of the thingy behind it be it another pedal or an amp.
2. What happens to the DC charge that leaked through the input cap - is it gonna spread to the input cable and stay around till the pedal is turned off and then it discharges?

1. Input signal suddenly prangs on a DC-brick wall..

2. It's just accumulated on cap's outer plate (the one facing to input..)..

[Lino22]

Antonis, thanks, i need to sort out one more thing.
So when you want to count the discharge time, do you take into account the capacity of the cap? I thought the charge is just sitting outside the cap, and so the cap doesn't play a role during the discharging process through the pull-down.

IMHO, there is no need for such resistors as far as IN-OUT are grounded in by-pass mode..
(unless we deal with a veeeeeeery slow trasition time switch in conjunction with a veeeeeery leaky cap..)

How would a pull-down help when you have already a 0 ohms "resistor" there? Even on extreme conditions?

[antonis]

So when you want to count the discharge time, do you take into account the capacity of the cap?

Of course but this isn't the case here..
(we just want to drive the amount of leaked charge to GND..)

I thought the charge is just sitting outside the cap, and so the cap doesn't play a role during the discharging process through the pull-down.

"Outside" isn't the proper denomination..
Leaked charge is built-up ON caps plate..

[Lino22]

"Outside" isn't the proper denomination..
Leaked charge is built-up ON caps plate..

Ah, i get it. So when it is eventually re-connected to the following pedal/amp, the newly connected portion has a different potential, the charge moves that way, hence it stops being static, and so it makes it through the input cap?

[Lino22]

One more thing - pedal will pop even when turned off. That means the input cap outer plate discharges and for that the charge can't be just sitting on the outer plate, it must be siting on the main input wire to discharge when turned off.

removed incorrect pictures

[antonis]

One more thing - pedal will pop even when turned off. That means the input cap outer plate discharges and for that the charge can't be just sitting on the outer plate, it must be siting on the main input wire to discharge when turned off.

No..

Charge is smart enough to not enter in a constrained road..  
It needs 2 stipulations: Voltage difference and conduit..