Hi to all
i'm new ,english is not my native language , i will do my best
well i have a problem with a crybaby GCB95 mod (the modification is true bypass and led ) , now i have removed the led and rewiring
the problem is a loud pop when I tun on the fist time only after I powered with a psu or battery.
it's weird because i have used the battery and a small amp using the batteries too, in short without any psu ,all with batteries , and i have tested with several different guitars
to be clear , guitars -> wah with battery -> black star with battery , and i have tried different cables too , i did it to avoid electricity issues
it's very weird because:
1) I power it with a psu or battery , i turn on with the footswitch and i got this loud pop , i turn off the wah and turn in the wah again the pop does disapear
2) I power off and power in , and the first turn on generate this pop
in short i got this loud pop only when i turn in the first time after powered in with a psu or battery , if i disconneted the power and re-enable the power i got this pop again only the first turn in
i have others pedal but they don't make such loud pop
I have used a small amp 3wat , but think about with a marshall tube amp 200W and a cabinet 4x12 400W
thanks
pop sounds
https://soundcloud.com/user-935315180/sound2?si=545c1293315e4c20aaab462bab345784 (https://soundcloud.com/user-935315180/sound2?si=545c1293315e4c20aaab462bab345784)
https://soundcloud.com/user-935315180/sound?si=0af2733b47ba482aba271589b5bf0405 (https://soundcloud.com/user-935315180/sound?si=0af2733b47ba482aba271589b5bf0405)
images sorry , i could upload maybe they are too big , my apologies
https://ibb.co/pLkXQy3
https://ibb.co/5vwhfYt
https://ibb.co/z625SFB
https://ibb.co/CmSsqGj
Wire your foot switch so that the circuit input is grounded in bypass mode.
Quote from: fowl on November 23, 2021, 11:37:37 AM
Wire your foot switch so that the circuit input is grounded in bypass mode.
hi
may i know what do you mean (it's wired like the standard way with a switch with 9 pins)?
might you please explain ?
Appreciate your help , sadly my english is poor
from "stinkfoot" site. You can google "3pdt bypass grounded input" for more pics of the same thing.
(https://i.postimg.cc/9DrK70XT/TB-3-PDT-LED.jpg) (https://postimg.cc/9DrK70XT)
Note that the three lower left pins (#2,3,6) could all be soldered together. In any case the ground for the LED goes to circuit in when the circuit is bypassed
But you also should check the amp...plug a cable in, power on (but volume down!) and see if there is any voltage on the other end of the cable. That makes pedals pop too. Called "pedal ventriloquism."
(https://1.bp.blogspot.com/-bST0fKeLXE8/VAZP02EFwnI/AAAAAAAAIkU/vP9Jm_npahU/s1600/Crybaby%2BGCB-95.png)
I don't know why R2 is omitted, I would fit 10M there if you don't want to change the switch wiring.
While you have it opened up, do check the quality of the solder joints on the connector pins, particularly the DC power socket.
ΙΜΗΟ, a 10nF (non-electrolytic) cap should be tooooo leaky for popping..
Quote from: Mantra on November 23, 2021, 11:47:25 AM
Quote from: fowl on November 23, 2021, 11:37:37 AM
Wire your foot switch so that the circuit input is grounded in bypass mode.
hi
may i know what do you mean (it's wired like the standard way with a switch with 9 pins)?
might you please explain ?
Appreciate your help , sadly my english is poor
(http://cdn.shopify.com/s/files/1/0174/5126/files/Grounded_True-Bypass.png?1326)
Hi
first I want to thank all of you
second it's the first time I got such problem , I mean the loud pop does happen only after powered in (with psu andor battery) and turned on the wah (only the first time) ,if i turn off/on many times i don't get any loud pop.
If I unplug the psu or the battery , I get again the same loud pop only the first time I turn on the wha
to avoid it , I use a volume pedal , powered on my psu , turn on the wah and turn off again the wha , and i don't touch anymore the psu
have you seen such issue ?
I re-wired without led yesterday again , checked all solder joints , and i use an electronic cleaner spray for each solder joints , they look clean and good
no luck
Quote from: antonis on November 23, 2021, 05:46:20 PM
ΙΜΗΟ, a 10nF (non-electrolytic) cap should be tooooo leaky for popping..
Quote from: anotherjim on November 23, 2021, 04:48:41 PM
I don't know why R2 is omitted, I would fit 10M there if you don't want to change the switch wiring.
While you have it opened up, do check the quality of the solder joints on the connector pins, particularly the DC power socket.
I re-wired without led , 1-2 bridge ,3-8 bridge , green -> 8 ,blues -> 9 , magenta -> 6 , cap to 5
the next steps will be replace the cap and the r2 resistor , i haven't never replaced the r2 restistor , it did come with it , gold red black , 12Ohm
i have upload new pictures (sorry i don't know how upload
https://ibb.co/6mYRZDW
https://ibb.co/TL9V2hZ
https://ibb.co/hgbH5g0
https://ibb.co/pjTKsHT
https://ibb.co/Js92Hvb
Quote from: Mantra on November 24, 2021, 05:10:10 AM
gold red black , 12Ohm
You probably mean BROWN, Red, Black (12R)..
Gold colour band isn't used for digit value but for tolerance (5%) only..
(and for band multiplier for values lower than 1 Ohm..)
P.S.
12 Ohms value for R2 equals to dead silent pedal.. :icon_wink:
(probaly R2 is of some other much higher value..)
Quote from: antonis on November 24, 2021, 05:47:20 AM
Quote from: Mantra on November 24, 2021, 05:10:10 AM
gold red black , 12Ohm
You probably mean BROWN, Red, Black (12R)..
Gold colour band isn't used for digit value but for tolerance (5%) only..
(and for band multiplier for values lower than 1 Ohm..)
P.S.
12 Ohms value for R2 equals to dead silent pedal.. :icon_wink:
(probaly R2 is of some other much higher value..)
Hi
sorry for my error
R2 resistor is gold -red - black -brown -> so it's brown - black -red = 1K
i could try 1M as suggested
thanks
I don't think your PCB as the parts numbered the same as the schematic I posted. I think it's a redrawn one and the CAD program used has given its own automatic numbering.
Other drawings I found don't show any antipop "R2" resistor. To fit one you may need to trace the input wire from the footswitch back to the PCB where it connects to the 10nF cap into the first transistor stage and find a 0v for the other end of the resistor.
I have this problem with my cry-baby. I have gone through the pedal and cant find the cause. My fluke meter does not read any voltage around the switch or jacks. I can say its not the switch, pot, coupling caps, filter cap. I tried the grounded input bypass switch circuit. Did not fix. Re-soldered any joint that looked iffy. If anyone comes up a solution, I will say thanks right now.
I think of this as a feature - pre solo attention getter.
Quote from: ronh on November 25, 2021, 07:55:46 PM
I have this problem with my cry-baby. I have gone through the pedal and cant find the cause. My fluke meter does not read any voltage around the switch or jacks. I can say its not the switch, pot, coupling caps, filter cap. I tried the grounded input bypass switch circuit. Did not fix. Re-soldered any joint that looked iffy. If anyone comes up a solution, I will say thanks right now.
I think of this as a feature - pre solo attention getter.
Hi Ronh
really ? have you the same problem?
I get this pop up only the first time i turn on the wah , after I power in with psu or battery. I don't get any pops the second time i turn it on , to get again the pop i have to power off , wait few seconds and power in again
have you installed a 9 pin or 6 pin foot switch ?
thanks
Quote from: Mantra on November 26, 2021, 01:45:10 AM
I get this pop up only the first time i turn on the wah , after I power in with psu or battery.
Replace reservoir electrolytic cap (C8 on anotherjim's posted schematic)..
You can get misbehaving ceramic caps in those Dunlop products - mechanical shock from operating the footswitch can bring it on. These are the little tubular mustard coloured ones.
A bad DC power jack can cause trouble. The charge stored in the reservoir cap "C8" can hide short period disconnections sometimes. Again, mechanical shock will bring one on.
Quote from: Mantra on November 26, 2021, 01:45:10 AM..pop up only the first time i turn on the wah , after I power in with psu or battery. I don't get any pops the second time....
So power-up before the crowd arrives.
My old PA system used to make a horrible racket at power-up, so I tried to get it all going before the doors opened. Or while the crowd was loud.
Mantra, my switch is a 6 pin, did not fix. As for C8 or power supply filter cap, removed, then replaced did not fix. The noise from a cap could be the problem. But which one? The pop is really loud, so there must be some gain attached to it, No? From what happens I think its a dc charge that gets discharged.
Power up, switch to effect mode pop. Switch back and forth no pop. Wait a couple of minutes, switch to effect on and pop.
Dunlop adding the input buffer probably makes this worse. The higher resistance in the buffer input bias slows the input cap charge rate making the pop longer and more obvious.
I suggest trying the original simple bypass that leaves the input always connected. That will prove if it is the input cap popping or, as I tried to point earlier, the pop is something else coinciding with the mechanical shock from operating the switch.
Quote from: anotherjim on November 27, 2021, 05:30:34 AM
The higher resistance in the buffer input bias slows the input cap charge rate making the pop longer and more obvious.
Sorry but I don't get you, Jim..
Buffers exhibit high input impedance and LOW output one..
The later is seen by the input cap so it is charged/disgharged quicker..
(actually, input cap side is more effectively grounded than in case of high value anti-pop resistor..)
I don't get you, Antonis.
(https://www.electrosmash.com/images/tech/crybaby/cry-baby-wah-gcb-95-bias.jpg)
How does Cin1 see Q0 output impedance?
There is no antipop resistor. A DPDT should ground the input in bypass like this...
(https://media.stinkfoot.se/2010/11/wahDPDTwiring.jpg)
...and if it does ground the input and stomping on it causes a pop - surely has to be a different fault?
It seems that some don't believe the fault can be at the DC jack because it pops with battery power too, but the battery + goes thru a contact in the DC jack!
Quote from: anotherjim on November 28, 2021, 06:58:54 AM
How does Cin1 see Q0 output impedance?
:icon_smile: :icon_smile: :icon_smile: :icon_smile:
I was talking about CryBaby input cap C1..
(which definatelly sees Q0 low output impedance hence no issue with charging it ..)
P.S.
Different "input" cap term definition.. :icon_wink:
anotherjim, I will check the DC jack. Its not the by-pass circuit and it does it on battery too. But, if its the jack, should it do on every transition from by-passed to effect? Never done it on the reverse.
As I said earlier, the 220uF power cap can hold enough charge to prevent momentary disconnection of the incoming power being heard. It's not a bad cap, it's just doing its job. So when you leave the pedal alone for a time that cap starts to discharge due to a high resistance contact somewhere and the PCB voltage slowly sags lower. Give it a shock and the connection makes better, the cap charges up rapidly and the voltage shoots up causing a pop noise. That's one scenario.
That DC socket has a hard life, it only has its contact pins soldered in the PCB to secure it. Not good practice IMHO, but we are where we are.
Quote from: anotherjim on November 29, 2021, 04:39:34 AM
As I said earlier, the 220uF power cap can hold enough charge to prevent momentary disconnection of the incoming power being heard. It's not a bad cap, it's just doing its job. So when you leave the pedal alone for a time that cap starts to discharge due to a high resistance contact somewhere and the PCB voltage slowly sags lower. Give it a shock and the connection makes better, the cap charges up rapidly and the voltage shoots up causing a pop noise. That's one scenario.
That DC socket has a hard life, it only has its contact pins soldered in the PCB to secure it. Not good practice IMHO, but we are where we are.
hi
i have recently replace it ( 220uF power cap) , no luck
the strange thing , i get another GCB95 (brand new) it's my friend new wah wah , "better truebypass" with 6 pin switch , no iusses at all , no pops
seeing i'm stubborn i will replace every caps and resistors , I have to find out the culprit
but on the net there are so many tutorials how mod + leds , but there really few tutorials to do a clean job for a simple trubypass mod .
often the leds are culprit
even in the screenshot posted above and the stinkfoot tutorials have few information and small images
i would like to see 2 decent tutorials , not for me but for many users that are going to make the first mod
by the way , about my friend brand new wah , i have made an "incision" very light (without pushing hard) with "throwaway" knife very sharp , re-wiring in "better truebypass" ,
ps i have tried "Basic true bypass" no loud pop , just an audible pop but ok
and it's sad that only me and ronh have such issue , seeing seems hard to find a fix
thanks
In some cases, it's realy difficult to distinguish mechanical pop from electrical one.. :icon_wink:
Ok just an update. I replaced the DC power jack. Did not fix. I suspect it will be a defective component. I had one in an amp. Measured good in every way but failed in circuit. As this only happens after power up. Will keep looking.
Another update. I may have the problem solved. On my pedal I measure 0.04Vdc on the blue wire coming from the board. Leaky cap. On the ElectroSmash schematic it is C5. If it is this cap, then the first discharge path, effect on, would cause the pop. The next device input resistance would provide a drain for this voltage. No? Effect off, wait for charge to build, effect on again and pop.
I will change this cap out to prove this. Mantra, if you are still following your post, measure the blue wire from the board. Should be 0Vdc with a cable plugged into the input. If it is this cap, a low cost fix.
When to found that voltage leak, was anything plugged into the output? Film caps rarely fail like that (can happen though). The DC can be from what you plug in to, but it also ought to make the wah pot crackle a bit. You can test with nothing plugged in the output jack.
However, if you had something like an amp with DC leakage to its input jack, you would notice with just a guitar plugged in as it makes the guitar volume pot crackle.
Quote from: ronh on December 10, 2021, 06:56:49 PM
Another update. I may have the problem solved. On my pedal I measure 0.04Vdc on the blue wire coming from the board. Leaky cap. On the ElectroSmash schematic it is C5. If it is this cap, then the first discharge path, effect on, would cause the pop. The next device input resistance would provide a drain for this voltage. No? Effect off, wait for charge to build, effect on again and pop.
I will change this cap out to prove this. Mantra, if you are still following your post, measure the blue wire from the board. Should be 0Vdc with a cable plugged into the input. If it is this cap, a low cost fix.
Hi Ronh
yes i'm following your progress
very interestating , on my wah should be the cap c6
but I will test c8 too
may I which tester do you use ? I have a cheap one here
here my c6 cap with the red arrow and the c8 with a blue arrow , is my wah schematic like yours?
https://ibb.co/X2CRg5V
thanks a lot , really appreciate a lot
Hi Mantra, I have the same board. To see if you have the same problem, you will have to disconnect the two blue wires that go to the switch. One blue wire will go to the pot, the other to the circuit board. You will measure the wire going to the board for a small dc voltage. Black meter lead to ground. I used the ring connection on the output jack. The red meter lead goes to the long blue wire. Make sure your hands are not touching the wire or ground. Your meter should be on dc voltage, low level. Hold for a minute, should show zero. If it is zero then it might be the other cap. Then you would have to measure the yellow wire going to the pot. As the blue wire is easiest to do, do that one first. After measuring you can re-install the two blues wires back onto the switch
Or you can just replace C6 and C8 on the board. Faster and easier. FYI, if your replacement caps are bigger, there is another hole connected to one of holes in use now. So a bigger cap can be installed. You will need a 0.22 uF, 25volt or greater film cap.
I am waiting for my replacements. If you replace and it fixes, please post the result for others.
Damn. I anwered something without realizing there was another page in the thread, so forget about this message.
I swapped out C6 & C8 and the problem is gone. No pop. Just posting this for the bots should someone else have this same problem. :)
Quote from: ronh on December 22, 2021, 06:13:02 PM
I swapped out C6 & C8 and the problem is gone. No pop. Just posting this for the bots should someone else have this same problem. :)
Hi @Ronh
great find!!!!
sadly i had to time to try to replace , but will do
in short you have replaced c6 and c8 caps with caps with same value ( 0.22 uF) but with 2 film caps (25volt) ?
does the wha tone changed?
again great find Ronh
thanks Rohn