# Parentheses mini fuzz only half working



## JulienD

Hi everyone,

I've contemplated building pedals for a long time, but took the plunge only a few weeks ago.
My first two (simple) builds went smoothly, but I ran into my first non-working build yesterday with a Parentheses Mini Fuzz, that is in fact half-working.

The bypassed signal is normal, and the boost side works perfectly, but the dist side doesn't.
I only get a very feeble amount of signal bleeding through a lot of white noise with all pots maxxed out.
I therfore assume that the issue doesn't reside in the power supply or jack in & out wiring, but most likely in the pcb, footswitch or pots wiring.

A few observations of interest:
- I don't have an audio probe (and won't have the parts to build one for at least another week or so), but I have a decent DMM.
- Offboard wiring and dpdt lug solder joints are ok, as evidenced by continuity tests with the DMM.
- The signal reaches at least the first components, but I can't test caps, diodes or transistors with a DMM.
- The IC is installed the right way, and so are the transistors (although I have no way to make sure they are spec-compliant).
- I've tried to switch them around (one by one, obviously), just to make sure the right orientation was specified on the PCB, to no success. It only makes a difference for Q5 (the last transistor before the volume pot, so post-IC and post-clipping); the white noise that I had with all pots maxxed out is now gone, but the small amount of guitar signal that was bleeding through is still audible, which leads me to believe that it comes from somewhere else than the intended signal path.
- Interestingly, the signal must reach at least as far as LED D6, located in one of the two clipping branches (and therefore post-IC), since it ligths up when I hit the strings.

So my questions for you guys are:
1) does the description of the issue and/or picture of my build ring a bell for some of you ?
2) how would you proceed from there?

Thanks a lot in advance!


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## Nostradoomus

What kind of JFETs did you use for Q1 and Q5 and where did you get them?


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## JulienD

Nostradoomus said:


> What kind of JFETs did you use for Q1 and Q5 and where did you get them?


It's a pair of PF5102, I got everything as a kit from musikding.de.


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## Bobbyd67

I know my first parenthesise fuzz I had a batch of  fake 308 ics so maybe try to swap it with a lm741 if you have one of those. Mine too the boost only the boost worked at first. With a 741 It fired up rigth away


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## Bobbyd67

Ah you got it as a kit :/ ... Then I would reflow the potiometers ... Half the time when I troubleshoot it's the source of the problem  Especially the amplitude and distortion pots


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## JulienD

Bobbyd67 said:


> I know my first parenthesise fuzz I had a batch of  fake 308 ics so maybe try to swap it with a lm741 if you have one of those. Mine too the boost only the boost worked at first. With a 741 It fired up rigth away


That's interesting. Is there anyway to tell if the 308 I have is fake?


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## JulienD

Bobbyd67 said:


> Ah you got it as a kit :/ ... Then I would reflow the potiometers ... Half the time when I troubleshoot it's the source of the problem  Especially the amplitude and distortion pots


You mean add solder and make sure the connection is properly made for each lug?


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## Bobbyd67

JulienD said:


> You mean add solder and make sure the connection is properly made for each lug?



Yep maybe i just don't apply enough solder when doing the pots but more than half my faulty builds are because of that. I find that applying some on both sides helps a lot.

I dunno if there's a sure way to test fake ICS but in this instance it just didn't have any output. Using the lm741 made me certain that the ic was at fault. I then went to a old electronic shop in Montreal and go some ua308, swapped the lm741 and got it working as it was intended . The lm741 worked fine but it didn't get as dirty as a 308!


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## Bobbyd67

But if you got it as a kit I doubt the ic is at fault but you never know :/


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## JulienD

I'll try both, just to be sure. I'll reflow the pots connexions tomorrow and order a couple ICs off amazon or something. If plan A doesn't work out, I'll wait for plan B to arrive in the mail. Worst case scenario is that I get a couple of spare ICs!


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## stefanos

Hi all. I have a similar problem.. I'm attaching my measurement on the pots (fully opened or closed). Is it normal what I measure in the two of them? When I remove the pots and measure them out of the pcb, I get the expected values..

For the IC, I guess by measuring the voltages on the legs, you could spot if there is something arriving/leaving..?


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## music6000

JulienD said:


> Hi everyone,
> 
> I've contemplated building pedals for a long time, but took the plunge only a few weeks ago.
> My first two (simple) builds went smoothly, but I ran into my first non-working build yesterday with a Parentheses Mini Fuzz, that is in fact half-working.
> 
> The bypassed signal is normal, and the boost side works perfectly, but the dist side doesn't.
> I only get a very feeble amount of signal bleeding through a lot of white noise with all pots maxxed out.
> I therfore assume that the issue doesn't reside in the power supply or jack in & out wiring, but most likely in the pcb, footswitch or pots wiring.
> 
> A few observations of interest:
> - I don't have an audio probe (and won't have the parts to build one for at least another week or so), but I have a decent DMM.
> - Offboard wiring and dpdt lug solder joints are ok, as evidenced by continuity tests with the DMM.
> - The signal reaches at least the first components, but I can't test caps, diodes or transistors with a DMM.
> - The IC is installed the right way, and so are the transistors (although I have no way to make sure they are spec-compliant).
> - I've tried to switch them around (one by one, obviously), just to make sure the right orientation was specified on the PCB, to no success. It only makes a difference for Q5 (the last transistor before the volume pot, so post-IC and post-clipping); the white noise that I had with all pots maxxed out is now gone, but the small amount of guitar signal that was bleeding through is still audible, which leads me to believe that it comes from somewhere else than the intended signal path.
> - Interestingly, the signal must reach at least as far as LED D6, located in one of the two clipping branches (and therefore post-IC), since it ligths up when I hit the strings.
> 
> So my questions for you guys are:
> 1) does the description of the issue and/or picture of my build ring a bell for some of you ?
> 2) how would you proceed from there?
> 
> Thanks a lot in advance!


The 2 wires circled need to be swapped around:


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## JulienD

music6000 said:


> The 2 wires circled need to be swapped around:



Shit you're completely right!
How could I have missed this when I have revied the wiring like a dozen times!?
Thanks a lot!


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## music6000

It will not fix your Issue as it just Grounds the Input in Bypass, The Led still works.
Do you have any Jfet's, ie  2N5457, 2N5458 
The PF5102's could be Faulty in Q1 & Q5.
It would be helpful if you showed a Pic of the Solder side of the PCB.


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## JulienD

music6000 said:


> It will not fix your Issue as it just Grounds the Input in Bypass, The Led still works.
> Do you have any Jfet's, ie  2N5457, 2N5458
> The PF5102's could be Faulty in Q1 & Q5.
> It would be helpful if you showed a Pic of the Solder side of the PCB.


Right, it's just the power supply for the status LED, I got excited over nothing...
Unfortunately, I have zero spare parts available at hand; the only thing I could do is cannibalize a triplet of 2N5088s I have in another pedal.
Here's a pic of the solder side, let me know if it's detailed enough.


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## JulienD

Can you tell I don't have a clue about what I'm doing? 
Joke aside, you gotta admit that the naming conventions are less-than-crystal-clear for newbies like me...


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## music6000

2N5088's are NPN transistors not Jfet's! 
The Solder on the  Op Amp pins looks suspect, Reflow with Solder with Op Amp removed.
Make sure you replace Op Amp in correct direction!
Make sure those Led wires are not touching the Board at any time.
Are those 2 Pots well insulated from the PCB, They can't touch at all?


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## JulienD

Will do, as well as reflow a couple of pots I was suggested, just to be sure.
I'll wrap the LED leads in duct tape, just to be safe, but I don't think they were touching anything when I last tested the circuit.
The two lower pots cannot touch the board, I've installed adhesive rubber pads on the back of their casings.

So basically, should all of the above fail, you're advising that I order a couple of PF5102, or 2N5457, or 2N5458 (as long as they're Jfets), swap them in and see what's up?
Someone also suggested that I do the same with the 308 (mine has been speculated to be a fake one by some), with a legit 308, or a ln741.
Any thoughts on that?


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## music6000

Lot of stuff coming out of China that looks like the real deal are Fakes!
Try and get some legit PF5102's &  LM308N's
I would be contacting Musikding & asking where their Transistors & Opamps are coming from if your replacements fix the problem.


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## stefanos

In case you have a multimeter, it's fairly easy to check if the Q1/Q5 work.. I also got a kit from musikding that had problematic 5102s.


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## JulienD

Hi everyone,

I've contemplated building pedals for a long time, but took the plunge only a few weeks ago.
My first two (simple) builds went smoothly, but I ran into my first non-working build yesterday with a Parentheses Mini Fuzz, that is in fact half-working.

The bypassed signal is normal, and the boost side works perfectly, but the dist side doesn't.
I only get a very feeble amount of signal bleeding through a lot of white noise with all pots maxxed out.
I therfore assume that the issue doesn't reside in the power supply or jack in & out wiring, but most likely in the pcb, footswitch or pots wiring.

A few observations of interest:
- I don't have an audio probe (and won't have the parts to build one for at least another week or so), but I have a decent DMM.
- Offboard wiring and dpdt lug solder joints are ok, as evidenced by continuity tests with the DMM.
- The signal reaches at least the first components, but I can't test caps, diodes or transistors with a DMM.
- The IC is installed the right way, and so are the transistors (although I have no way to make sure they are spec-compliant).
- I've tried to switch them around (one by one, obviously), just to make sure the right orientation was specified on the PCB, to no success. It only makes a difference for Q5 (the last transistor before the volume pot, so post-IC and post-clipping); the white noise that I had with all pots maxxed out is now gone, but the small amount of guitar signal that was bleeding through is still audible, which leads me to believe that it comes from somewhere else than the intended signal path.
- Interestingly, the signal must reach at least as far as LED D6, located in one of the two clipping branches (and therefore post-IC), since it ligths up when I hit the strings.

So my questions for you guys are:
1) does the description of the issue and/or picture of my build ring a bell for some of you ?
2) how would you proceed from there?

Thanks a lot in advance!


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## JulienD

stefanos said:


> In case you have a multimeter, it's fairly easy to check if the Q1/Q5 work.. I also got a kit from musikding that had problematic 5102s.


I do have one. How do I do that?


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## stefanos

put the power to the pedal, use the voltage measurement on the multimeter. One probe to the central leg and the other probe to the side ones. You should have a non-zero value. Something like 8.5 and 0.25 if I remember correctly.


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## JulienD

stefanos said:


> put the power to the pedal, use the voltage measurement on the multimeter. One probe to the central leg and the other probe to the side ones. You should have a non-zero value. Something like 8.5 and 0.25 if I remember correctly.


Great! Do I need to have some guitar signal going through the circuit, or is the power supply enough?


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## stefanos

nope.. just the power supply.


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## JulienD

I have 8.8V and 0.3V for Q1 and 8.8V and 0.23V for Q5.
So they are fine, right?


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## stefanos

I guess.. Try to check the LM308. I have my measurements here https://forum.pedalpcb.com/threads/parentheses-fuzz-octave-problem.2864/ in case they help. But my build also doesn't work, but could be due to another problem..


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## JulienD

Here are the voltages I've measured on the IC pins, numbered as in the schematic attached.
1 : 9.1V
2: 4.6V
3: 4.2V
4: 0V
5: 0V
6: 4.6V
7: 9.1V
8: 9.1V

I can't help but notice some differences between your measurements and mine; did you use the same pin order?
Anyway, the symptoms you describe in your post are exactly the same as mine.

I've swapped the boost side LED power supply cables that were inverted on my build (what an idiot), tried to re-flow the IC socket pins, made sure that the LED leads were not touching anything, and checked that all pots have good continuity.
None of that worked.

I could order replacement Jfets and ICs, but considering the current delivery lead times, I guess all I have left to do is wait for my next order to show up in the mail (hopefully in the coming week) and build an audio probe.
Have you tried that?


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## stefanos

nope.. I'm also not an expert on these measurements.. I was hoping that someone that has a working version could compare these..?

I usually order components from european based ebay sellers and that leads to fast deliveries.


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## JulienD

Yeah, that'd be helpful. Who are your reference supppliers, usually?
I haven't had to order single components yet (as opposed to ordering them as kits), but I may have too in the near future...


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## stefanos

not sure if I can advertise here.. Just log in to ebay.fr or .co.uk and select sellers in europe. there are a couple in germany and GB that are fast shippers. 

I hope someone from this forum could verify these measurements..  or provide some help.


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## JulienD

Hi again everyone,

I received new components today, and was able to build an audio probe.
The results are pretty clear: the signal doesn't get past Q1. I have a crystal clear sound on my probe until leg 3 (and I do mean leg, not solder side of the socket), and nothing on leg 1 (which is normal, as it's the power supply) but nothing on leg 2 either (which isn't normal, as it's supposed to be the output).
I've double checked all components located directly after Q1: leg 2 of R4, and both sides of C3 and C10. Zero audible signal, regardless of the octave pot setting.
Finally I've tried swapping around the two PF5102s in the circuit (the other being Q5), which makes zero difference at all.
I want to jump to the conclusion that both of the PF5102s I got in the kit are fake (statistically, one non-working part out of several identical ones should be considered faulty, two out of two means fake).
Do you agree, or am I missing something?


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## Nostradoomus

Seems to be the most common problem lately with this build. I used 2n5458s in all my rat/parentheses builds and never had a problem.


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## Robert

JulienD said:


> I want to jump to the conclusion that both of the PF5102s I got in the kit are fake (statistically, one non-working part out of several identical ones should be considered faulty, two out of two means fake).
> Do you agree, or am I missing something?



I can't find the thread, but I think someone else in the recent past came to this same conclusion.

Shoot Klaus at Musikding an email, I'll do the same.     I doubt he's aware that there is an issue, I certainly don't think he's intentionally selling fakes (if that is the case).


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## stefanos

Wouldn't you get false readings (like nulls?) on the Q1/Q5 if they are the problem?


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## JulienD

Robert said:


> I doubt he's aware that there is an issue, I certainly don't think he's intentionally selling fakes (if that is the case).


Oh I'm certainly not implying he is, but if they are fake indeed, it's best that he knows it as soon as possible, so he can fix the issue with the kits he's shipping for the short term and with his supplier for the long term.


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## JulienD

stefanos said:


> Wouldn't you get false readings (like nulls?) on the Q1/Q5 if they are the problem?


That's kind of what I was wondering, too...


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## Mendelas

Hi,

Just to add myself to the crowd -I just finished the same kit from Musikding as OP-, things are not working at all, but I can confirm that I have a valid signal path from input to output when jumping G & S on both 5102s (Q1 &Q5). If I'm not mistaken, that would support the hypothesis of duds/non-working JFETs.


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## JulienD

Mendelas said:


> Hi,
> 
> Just to add myself to the crowd -I just finished the same kit from Musikding as OP-, things are not working at all, but I can confirm that I have a valid signal path from input to output when jumping G & S on both 5102s (Q1 &Q5). If I'm not mistaken, that would support the hypothesis of duds/non-working JFETs.


I'm starting to sense a pattern here. I've written to Musikding, let's see what they answer.


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## stefanos

Well.. I changed the 5102s with 5458s and it worked.. So, I guess that's the way to go..


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## JulienD

Robert said:


> I can't find the thread, but I think someone else in the recent past came to this same conclusion.
> 
> Shoot Klaus at Musikding an email, I'll do the same.     I doubt he's aware that there is an issue, I certainly don't think he's intentionally selling fakes (if that is the case).


Guys, stop everything, I found the problem: it's the pinout on (our?) PF5102s that's not compatible with the way the PCBis laid out.
I reversed pins 2 and 3 (source and gate, is it?) and it worked right away.
I'll order some 5458s for the long term (as Stefanos suggested), and encourage you to do so to, but if you want to get your builds working until they get there, you know what to do!

Thanks a lot to the community for the appreciated help!


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## JulienD

Hi everyone,

I've contemplated building pedals for a long time, but took the plunge only a few weeks ago.
My first two (simple) builds went smoothly, but I ran into my first non-working build yesterday with a Parentheses Mini Fuzz, that is in fact half-working.

The bypassed signal is normal, and the boost side works perfectly, but the dist side doesn't.
I only get a very feeble amount of signal bleeding through a lot of white noise with all pots maxxed out.
I therfore assume that the issue doesn't reside in the power supply or jack in & out wiring, but most likely in the pcb, footswitch or pots wiring.

A few observations of interest:
- I don't have an audio probe (and won't have the parts to build one for at least another week or so), but I have a decent DMM.
- Offboard wiring and dpdt lug solder joints are ok, as evidenced by continuity tests with the DMM.
- The signal reaches at least the first components, but I can't test caps, diodes or transistors with a DMM.
- The IC is installed the right way, and so are the transistors (although I have no way to make sure they are spec-compliant).
- I've tried to switch them around (one by one, obviously), just to make sure the right orientation was specified on the PCB, to no success. It only makes a difference for Q5 (the last transistor before the volume pot, so post-IC and post-clipping); the white noise that I had with all pots maxxed out is now gone, but the small amount of guitar signal that was bleeding through is still audible, which leads me to believe that it comes from somewhere else than the intended signal path.
- Interestingly, the signal must reach at least as far as LED D6, located in one of the two clipping branches (and therefore post-IC), since it ligths up when I hit the strings.

So my questions for you guys are:
1) does the description of the issue and/or picture of my build ring a bell for some of you ?
2) how would you proceed from there?

Thanks a lot in advance!


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## Bobbyd67

Nice !!! I love a happy troubleshooting ending !!!
I got a thorpy mushroom cloud build that I can't get to work :/ might have to do a thread myself T_T


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## Mendelas

Thanks mate ! You were totally right, nice troubleshooting!


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## evilarsen

Some of us have problem with PF5102 (from Musikding) they're fonctionnal but pin 2 and 3 are inverted


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## JulienD

evilarsen said:


> Some of us have problem with PF5102 (from Musikding) they're fonctionnal but pin 2 and 3 are inverted


Yeah, that's what I found out experimenting with the pinning. It makes for a messy wiring, but at least, it works until I can get my hands on 2n5458s!


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## jimtom

Hi, I have the same kind of problem.
The distortion side lets a clean signal through without any distortion but the octave side works. The PF5102s were replaced by 2N5457s and I was wondering if this could be the problem. Should I replace them with 2N5458s?


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## Nostradoomus

jimtom said:


> Hi, I have the same kind of problem.
> The distortion side lets a clean signal through without any distortion but the octave side works. The PF5102s were replaced by 2N5457s and I was wondering if this could be the problem. Should I replace them with 2N5458s?



Does the tone control do anything? The jfet is just a unity gain buffer so it sounds like that is working. What kind of opamp did you use and where did you get it?


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## jimtom

The pedal actually works fine. I had trouble understanding how it worked...


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