First Fuzz Build Help!

[Rick1114]

Hello Everyone,
I just finished putting together my first Fuzz kit. It is an Os Mutantes Fuzz from 3DPT. They sell these through Amazon for $50, which I though was pretty good deal. It was a fairly straightforward build just sorting out the part values is prob the most difficult task (parts just come in a bag together) so you do need to be proficient with a multi-meter or with reading the charts online. I did make a big mistake and had one of the Silicon Diodes wired in backwards (those darn things are hard to see for my middle aged eyes). I fired it up and when I realized it wasn't working properly (Weak Fuzz, Noisy), I found the Diode mistake. Anyway i reversed the diode, and it still doesn't work right so I think I fried it. Anyway, I wanted to check what I could possibly substitute this part with and if it responsible for the pedal not working (or if there may be other issues). It is a 1N60P Silicon Diode as seen on the top left of the circuit seen below. The pedal works when bypassed, when engaged I hear weak noisy fuzz output in one switch position (top right switch) and nothing in the other.

Anyway, I know this is a newbie mistake, but it is my first completed build, so be merciful on me! Any help would be greatly appreciated!

Best regards,
Rick         

[GGBB]

It is extremely unlikely that reversing that diode would have blown it or caused the problem you are having. First check the orientation of your transistors, then check for bad solder joints and damaged/defective caps. An audio probe would be a good tool to use to figure out where in the circuit the sound goes bad.

[Cozybuilder]

I don't see the tab on Q1- its likely this is installed incorrectly.

[Rick1114]

The Tab is there just hard to see in the pic! I have the tabs (emitters) installed correctly. Then I have the middle (base) in the middle slots and the collector on the opposite end. I just rechecked all my part values and they pan out. I think (hope) my jacks seem to be installed correctly. So either I have a cold solder joint, a bad part or my pots installed wrong. I'm gonna check those things and order an audio probe (I need it for other projects as well). Can anyone suggest a good inexpensive one? Any more suggestions on the build would be appreciated. Volume and fuzz knobs seem to working, it's just really noisy and in the other switch position all I hear is a high picthed squeal!!!

[duck_arse]

do you have a multimeter? that is the most important tool for debug. as for the audio probe, you make that yourself, there is a number of posts in a number of places on how to do it. v. easy.

can you take another photo, showing us the jack and DC wirings?

[bluebunny]

. . . and order an audio probe

"Order"?  It's a capacitor and a bit of cable.  [link]

[Rick1114]

Ok, I get it..Audio probe sounds like an expensive device  . I'll make one up soon as I'm gonna need it for a delay project I'm working on. Anyway, I did re-solder the joints, thought there may be a solder bridge to the volume pot that I fixed but the pedal still sounds like pure awfulness. Also the Q1, Q2 sockets are really loose and not locking the BC109s well at all. I'm starting to wonder about those....Here are pics of my jacks &power connections...

Best regards,  Rick

[Cozybuilder]

This looks more like the Madbean Deadpool- see this thread http://www.diystompboxes.com/smfforum/index.php?topic=95712.0

http://www.madbeanpedals.com/projects/Deadpool/docs/Deadpool.pdf

Considering you have verified components values & orientations, my guess is that there is a dodgy solder joint. Some of the ones in the photos look iffy.

Edit: Deadpool link added

[GGBB]

The Tab is there just hard to see in the pic! I have the tabs (emitters) installed correctly.

Installed correctly according to what?

I see what looks like it might be a tab, and I see a lowercase 'e' where it is inserted, but the transistor shape drawn on the PCB for Q1 is oriented opposite to Q2 relative to their respective 'e' marks. That's one possible error on the PCB, unless the build specifies particular transistors that are different and have opposite pin-outs. So Q1's 'e' should be a 'c'. Also, when I look at the traces on both sides of the PCB, I see that the other end of Q1 is connected to ground, and according to the schematic, Q1 emitter goes to ground - confirming that the Q1 'e' is definitely wrong.

So just for fun, try reversing Q1. I haven't bothered looking at Q2, but if I'm right about Q1, then the whole PCB should be treated as suspect - verify Q2 and anything else where pin-out or polarity matters.

EDIT: I don't know if 3PDT gave you a build guide with the PCB, but if they did you might want to look through it to see if the 'e' error is noted. These types of errors happen but usually they are noted in the documentation somewhere when otherwise the PCB is fine. If it's not noted, you should report it to 3PDT.

[Rick1114]

The Tab is there just hard to see in the pic! I have the tabs (emitters) installed correctly.

Installed correctly according to what?

I see what looks like it might be a tab, and I see a lowercase 'e' where it is inserted, but the transistor shape drawn on the PCB for Q1 is oriented opposite to Q2 relative to their respective 'e' marks. That's one possible error on the PCB, unless the build specifies particular transistors that are different and have opposite pin-outs. So Q1's 'e' should be a 'c'. Also, when I look at the traces on both sides of the PCB, I see that the other end of Q1 is connected to ground, and according to the schematic, Q1 emitter goes to ground - confirming that the Q1 'e' is definitely wrong.

So just for fun, try reversing Q1. I haven't bothered looking at Q2, but if I'm right about Q1, then the whole PCB should be treated as suspect - verify Q2 and anything else where pin-out or polarity matters.

EDIT: I don't know if 3PDT gave you a build guide with the PCB, but if they did you might want to look through it to see if the 'e' error is noted. These types of errors happen but usually they are noted in the documentation somewhere when otherwise the PCB is fine. If it's not noted, you should report it to 3PDT.

GGBB,
I think you are on the $$ here. I reversed Q1 and now there no more sqealing and I can can kind of play with the different positions. Still lots of hiss when engaged, and the pots not working correctly. Seems I get more fuzz with knob down and the volume adds treble? I dunno I could only try for a moment as I have visitors coming and the wifes had it with my guitar antics for the day. So ill have to take a closer look later. I don't have much troubleshooting backgroung but am a quick learner....I thought this should have been a paint by numbers project.... 

[Rick1114]

Ok, Did my chores and sat down and played with it for a few minutes. I can get fuzz but overall the pedal is very noisy (background hiss), and the controls don't seem to do what the are supposed to. They do something but hard to describe exactly.

[GGBB]

I thought this should have been a paint by numbers project

Not at all an unreasonable assumption since the DIY pedal kit market is to some extent marketed that way. But they made a mistake, and sometimes we make build mistakes whether due to lack of experience or momentary inattentiveness, so the onus lies on us to be able to do some debugging. Sounds like you are getting there though with this one - keep at it.

[Rick1114]

I thought this should have been a paint by numbers project

Not at all an unreasonable assumption since the DIY pedal kit market is to some extent marketed that way. But they made a mistake, and sometimes we make build mistakes whether due to lack of experience or momentary inattentiveness, so the onus lies on us to be able to do some debugging. Sounds like you are getting there though with this one - keep at it.

So far looking at the parts list, it looks like Madbeans version. I guess the good news for me is, I could follow his schematic and try to put the darn thing together correctly. I always wanted to learn about fuzzes anyway as I can't afford boutique stuff right now and I'm just starting to get into fuzz sounds. So hopefully I could eventually mod it to my tastes and to sound good with my amp....

[Rick1114]

Just to follow up, the pedal is working now! Q1 needed to be reversed as suggested by GGBB (thank you!). The pedal was pretty darn noisy though but I noticed when I lowered the bias the hiss would go down, so I suspected the trannies. Went to radio shack and found a couple of 2n3904 transistors (a suitable replacement according to madbeans build notes). After a bit of experimentation, I used the bc109 for Q1 and a 2n3904 for Q2. That brought the noise level down substantially while retaining some dynamics. Overall it's a cool little box, def high gain, fun to play around with. I might experiment with some different transistors.

If possible eventually I'd like to reverse the "fat" control knob, as it seems counterintuitive to have the sound become less saturated as you turn the knob up. If you reversed it, it seems it would function more like a proper gain or saturation control (Pots are board mounted so not sure how this could be done).

[GGBB]

If possible eventually I'd like to reverse the "fat" control knob, as it seems counterintuitive to have the sound become less saturated as you turn the knob up. If you reversed it, it seems it would function more like a proper gain or saturation control (Pots are board mounted so not sure how this could be done).

Desolder the two outside pins, carefully bend them away from the PCB, solder wires to them and connect them to the PCB reversed. Heat shrink is recommended.

[Cozybuilder]

According to the schematic the wiper of the FAT pot is tied to pin 3, which goes to ground, while pin 1 is tied to D1. To reverse the pot, simply cut the trace to pin 2, and hardwire it to the other lug. First verify which lug the wiper is tied to- just follow the traces to make that determination. As you've seen the PCB may not be completely accurate, so you need to make the tracing to see what is really wired together.

[GGBB]

According to the schematic the wiper of the FAT pot is tied to pin 3, which goes to ground, while pin 1 is tied to D1. To reverse the pot, simply cut the trace to pin 2, and hardwire it to the other lug. First verify which lug the wiper is tied to- just follow the traces to make that determination. As you've seen the PCB may not be completely accurate, so you need to make the tracing to see what is really wired together.

Which schematic are you looking at? Are you sure it's the same as the 3PDT PCB? I was looking at the pictures of the PCB itself, which does not correspond to your description.

Rick - Cozybuilder might be right, and if he is, it is easier to just pull/cut the wiper pin from the PCB and tie it to pin 1. But if he's wrong, then that won't work. My suggestion works no mater what the circuit actually is.

EDIT: Looks like Cozy is right and I am not good and mentally reversing left and right when comparing opposite sides of a PCB. 

[Rick1114]

Just an fyi, this pedal has been working perfectly since I reversed Q1 per GGBB's instructions! I decided to keep the fat control unchanged once I got my head around how it works. 

I don't know how to measure hfe yet but It sounds great with the BC109 in Q1 and 2N3904 in Q2 (I had a few of each that I played around with until I found a good combo). Suprisingly really quiet and also really high gain. I can get my amp to feedback at bedroom levels...lotsa fun. I plan more learning more and have a few more Silicon transistors coming soon to try.  Thanks again everyone for their help!

One issue I do have is when I put my nux loopcore in front of it, the sound comes in and out. I'd like to loop some soundscapes with this this, as it seems like it would be great for that sort of thing. Anyone know what could cause this? I believe I've heard about these kind of issues with fuzz pedals before....

[nocentelli]

If you want to capture the sound of the pedal, you'll need to go guitar->fuzz->looper, i assume from your description you have the looper first.