# Parentheses Fuzz V1 - Does'nt work, clean build.. pls help a first time builder....



## Abyssmal (Aug 29, 2020)

Parentheses Fuzz V1 - Does'nt work, clean build.. pls help a first time builder....
I'm used to solder eurorack smd as small as 0402 so i don't think the problem is the soldering.
Maybe a bad component but again i bought from reputable sources...
Maybe bad wiring?
I get no output... except in bypass mode it sounds good, but the fuzz and octave is not present, just a faint distorted guitar signal weird signal full of noise.
The boost section seems to work but i'm not 100% sure.
What could be my issue?
Wiring for the left and right 3pdt footswitches are all inline with the holes on the pcb, i tested for continuinty and it made sense but i'm not sure?
I measure +9v at the + sign at the middle top of the pcb
All 3 leds on the front panel works, turns off and on if i hit the footswitches.
The led inside the case lights up depending of the potentiometer settings.
I use a legit lm308 from small bear
germanium diodes and pretty much everything else is from tayda
I measure 9v at pin 1 and 4.5v at pin 8 of lm308 (arent they suposed to be not connected?)
-v power pin is 0v and +v pin is 9v on lm308
Thanks a lot


----------



## Chuck D. Bones (Aug 29, 2020)

Check these voltages:
Q1 source
Q5 source
IC1 pin 6

Did you sub any parts or did you follow the BOM 100%?

Don't bother measuring pins 1 & 8.  They ARE connected inside the opamp.


----------



## Abyssmal (Aug 29, 2020)

The lm308N is from banzai website.
I also tried lm308n from ebay.
I did not substitute any part, i followed the bom as accurate as i could.
I have a scope i can probe things

both Germanium diodes are from tayda, maybe i installed them the opposite way?

IC1 pin6 is 4.5vdc (a distorted waveform)
IC1 pin3 is 4.3vdc (a steady dc voltage)

C5 is 0.8v at one pin and 4.1v at it's other pin. (steady voltages shown on the scope, no waveforms)

Q1 - pf5102:
pin1 drain= 9vdc
pin2 source = 0.2vdc
pin3 gate = 0vdc

Q5 - pf5102
pin1 drain= 9vdc
pin2 source =  0.24vdc
pin3 gate = 0.4vdc


got theses pf5102 from ebay








						10pcs PF5102 JFET N-CH 40V 625MW TO92 Fairchild NEW  | eBay
					

Find many great new & used options and get the best deals for 10pcs PF5102 JFET N-CH 40V 625MW TO92 Fairchild NEW at the best online prices at eBay! Free shipping for many products!



					www.ebay.ca
				




bs170 also from ebay








						20PCS NEW BS170 MOSFET N-CH 60V 500MA TO-92 FSC  | eBay
					

Find many great new & used options and get the best deals for 20PCS NEW BS170 MOSFET N-CH 60V 500MA TO-92 FSC at the best online prices at eBay! Free shipping for many products!



					www.ebay.ca
				





I'm looking at the schematic but i have a bit of difficulty to understand how the references link are made


----------



## Chuck D. Bones (Aug 29, 2020)

IC pin6 is 4.5vdc - *GOOD*

Q1 - pf5102:
pin1 drain= 9vdc - *GOOD*
pin2 source = 0.2vdc - *BAD*
pin3 gate = 0vdc - *GOOD*

Q5 - pf5102
pin1 drain= 9vdc - *GOOD*
pin2 source =  0.24vdc - *BAD*
pin3 gate = 0.4vdc - *BAD*

Q1 & Q5 are out of spec at best, may not even be JFETs.

This is what happens when you buy JFETs on eBay.  To paraphrase Forrest Gump: _"Buying transistors on eBay is like a box of chocolates, except most of the chocolates have been replaced with turds."_

So what to do about it?
Buy JFETs from a know good supplier:
PedalPCB
Small Bear
DigiKey
Mouser
Arrow
... to name a few.

They don't have to be PF5102 in this circuit.  Most good N-channel JFETs will work as source-followers in this circuit.  Ideally, you want ones with Vp close to -4.5V, but anything from -2V to -7V will work.

Are you able to test JFETs, i.e. measure Idss & Vp?

Just for completeness, measure Q6's drain voltage.  Should be around 5V.


----------



## Nostradoomus (Aug 29, 2020)

Your 5102 are probably bad or fake if they’re from a Chinese eBay seller. I found 2n5458 works the best in Rat circuits. BS170 are still in production so those should be fine... if your boost works that’s the only thing the bs170 is involved with so that’s a plus. Try some 5458s from smallbear or stompboxparts.

Edit: damnit Chuck! Haha


----------



## Abyssmal (Aug 29, 2020)

hahah yeah i'll replace them for good ones. The ebay seller had 99% good feedback... anyways loll thanks for the help i will update this post when i receive the new ones. I never tested jfets but i could probably do it if i check how...  I might have other n-ch jfet here to try meanwhile...

Q6 - BS170:
pin1 drain= 4.6vdc
pin2 source = 2.3vdc
pin3 gate = 0.2vdc


----------



## Chuck D. Bones (Aug 29, 2020)

Ha ha ha ha, beatcha that time!


----------



## Abyssmal (Aug 29, 2020)

Nostradoomus said:


> Your 5102 are probably bad or fake if they’re from a Chinese eBay seller. I found 2n5458 works the best in Rat circuits. BS170 are still in production so those should be fine... if your boost works that’s the only thing the bs170 is involved with so that’s a plus. Try some 5458s from smallbear or stompboxparts.
> 
> Edit: damnit Chuck! Haha



I'm sure i have some 2n5458 here, i'll try that !


----------



## Nostradoomus (Aug 29, 2020)

Mind the pin out!


----------



## Chuck D. Bones (Aug 29, 2020)

Norke said:


> hahah yeah i'll replace them for good ones. The ebay seller had 99% good feedback... anyways loll thanks for the help i will update this post when i receive the new ones. I never tested jfets but i could probably do it if i check how...  I might have other n-ch jfet here to try meanwhile...
> 
> Q6 - BS170:
> pin1 drain= 4.6vdc
> ...



Good feedback on eBay doesn't mean anything.  What else was that guy selling?  Umbrellas?

I have posted in these forums, more than once, instructions on how to measure Vp & Idss.  It's easy to do.

Q6's drain voltage is good.  The gate voltage measurement is bogus, your DMM is loading down the circuit.  That's why I didn't ask you to measure it.


----------



## Abyssmal (Aug 29, 2020)

Ok thanks guys  will order the proper ones now.


----------



## Abyssmal (Aug 29, 2020)

Nostradoomus said:


> Mind the pin out!


 2n5458 and pf5102 are the same pinout isnt it? What pinout are you refering to?


----------



## Nostradoomus (Aug 29, 2020)

That’s all I was saying, check and make sure


----------



## Abyssmal (Aug 29, 2020)

Nostradoomus said:


> That’s all I was saying, check and make sure


ha okay good


----------



## Abyssmal (Aug 29, 2020)

holyyyy it sounds nice
It works now with the 5458 i got from ebay
just 2 weird thing, is it normal the switch makes the volume a lot louder when its in the middle position?
and the octave function kinda gates the signal a little, seems like it has a slight delay before i hear my played note and when i turn it off using the footswitch it's silent for half a second. All this is normal?


----------



## Chuck D. Bones (Aug 29, 2020)

Try reversing D2 & D3.  There has been a fair amount of discussion as to which way they should be facing.


----------



## Abyssmal (Aug 29, 2020)

Chuck D. Bones said:


> Try reversing D2 & D3.  There has been a fair amount of discussion as to which way they should be facing.



The choking gated thing was because my schecter hellraiser emg has too much output, its overloading the input i think, when i back off the volume on the guitar it sounds less muddy and more like its suposed to be.

I tried reversing d2 and d3 but i cant really hear difference right now.

I think the octave function is not working... or if thats how its suposed to be it is a subtle octave effect... it changes the sound but im not even sure to hear an octave, is it octave down or up from the root note?

Heres a video (the octave knob was fully on):








						VID_20200829_205557.mp4
					

1 file sent via WeTransfer, the simplest way to send your files around the world




					we.tl


----------



## Abyssmal (Aug 30, 2020)

Chuck D. Bones said:


> So what to do about it?
> Buy JFETs from a know good supplier:
> PedalPCB
> Small Bear
> ...




Is banzai legit for transistors and parts?


			Banzai Music GmbH
		


Where would you get PF5102
Out of stock everywhere except banzai


----------



## Chuck D. Bones (Aug 30, 2020)

I have no personal experience with Banzai.  From what I read in these forums, some people have had issues with some of their parts.  You'll have to draw your own conclusions.  I got mine from Small Bear.  If Steve is out of stock, he will get more.  It appears that the lockdown has increased the demand for pedal parts, go figure!


----------

