The Fuzz Face Explorer Board Kit - a learning rig for this popular fuzz circuit and a great way to demo new and unexplored transistors for Fuzz

[SillyOctpuss]

Thank you, @SillyOctpuss! I don't know how I managed to get turned around when I ordered those transistors. My plan had been to start with NPN germanium. Ah well, baby steps - let's just get something working to start with.

Yeah definitely get those ones, measure their hfe, let me know what they are and I'll help you pick which ones to try in which spots. A silicon fuzz face is much easier to nail than a germanium. Once you've got a sound you're happy with move onto germanium. Because you have to deal with leakage, hfe and temp with germanium it's a bit more of a challenge to get a fuzz face just right.

 

[mbenigni]

Yeah definitely get those ones, measure their hfe, let me know what they are and I'll help you pick which ones to try in which spots. A silicon fuzz face is much easier to nail than a germanium. Once you've got a sound you're happy with move onto germanium. Because you have to deal with leakage, hfe and temp with germanium it's a bit more of a challenge to get a fuzz face just right.

Thanks for the recommendation on the TC-1 - works great! Here are the hFE values for the 4 transistors I have on hand:

125
137
163
180

Thoughts?

 

[SillyOctpuss]

Thanks for the recommendation on the TC-1 - works great! Here are the hFE values for the 4 transistors I have on hand:

125
137
163
180

Thoughts?

They're a bit low for bc108b, I think the gain range for 108b is 200 - 450hfe.

I'd use the 163 in Q1 and 180 in Q2. I'd bias Q2 to about 5v with your trimpot, play it and see what you think.

 

[mbenigni]

They're a bit low for bc108b, I think the gain range for 108b is 200 - 450hfe.

I'd use the 163 in Q1 and 180 in Q2. I'd bias Q2 to about 5v with your trimpot, play it and see what you think.

Will do. Thanks again!

 

[mbenigni]

This project is starting to bring my ignorance into stark focus.

I completely overlooked the fact that two of the capacitors in the circuit are polarized and one is not. Is this strictly necessary either way in any of the 3 positions, or do you just need to be sure the capacitance is correct? What's weird is that the diagram clearly shows a polarized capacitor near the signal input, but in the photo of the board, that's the only one that looks similar to the (non-polarized) capacitor I pulled out of my variety pack. (I used similar capacitors for all of three positions, and now I'm wondering if I should expect a puff of smoke when I first power up. )

Can anyone give me a clue as to what part numbers to use in each of the three positions in this diagram? What do I need to be concerned with besides capacitance? Material, voltage/power rating, polarity, etc.?

Lastly - probably a question for @huntingtonaudio - what do you recommend for connecting power and signal I/O to these SIP connectors? Is there a standard size designation I can use to order wires prepped for mounting? Should I just solder wire directly to the pins on the board?

And lastly lastly... I see the mounting points for input hot and output hot, but where's the best place to connect ground for each of these? Should I be sharing the "-" terminal of Vin? It looks like I'd want to share the ground terminal at the output signal potentiometer?

 

[SillyOctpuss]

Putting a polarised cap in the wrong way round will release white magic smoke eventually. It might work for a little bit but it will blow out sooner rather than later. You can, however, fit a non polarised cap instead and it will still work fine, it's just hard to find film caps in the same values as polarised electrolytics, the 2.2uf input cap is normally an electrolytic but you could replace it with a 2uf film instead. I'd stick with a polarised electro myself though. The input cap size helps set the amount of bass allowed into the circuit so you can always go down a value and fit 1uf. That's the value analog Mike fits to the sun face pedals, again you can fit film but I'd stick with the polarised electro the schematic calls for.

Not sure what you actually mean asking about part numbers? Do you mean the three caps?

 

[mbenigni]

Putting a polarised cap in the wrong way round will release white magic smoke eventually. It might work for a little bit but it will blow out sooner rather than later. You can, however, fit a non polarised cap instead and it will still work fine, it's just hard to find film caps in the same values as polarised electrolytics, the 2.2uf input cap is normally an electrolytic but you could replace it with a 2uf film instead. I'd stick with a polarised electro myself though. The input cap size helps set the amount of bass allowed into the circuit so you can always go down a value and fit 1uf. That's the value analog Mike fits to the sun face pedals, again you can fit film but I'd stick with the polarised electro the schematic calls for.

Not sure what you actually mean asking about part numbers? Do you mean the three caps?

Thanks for this! I ordered a bzillion capacitors thinking I'd wind up with everything I needed forever LOL...

EEEEE 30 value 300 pcs Multilayer Monolithic Ceramic Capacitor assortment kit 10pf－10uF Individual Box Lid pf nf uf (300 pcs)

...but I didn't account for anything besides capacitance. Even then, I overlooked the fact that this assortment doesn't include the 22uF cap required between the Fuzz pot and ground. I figured I'd just wire a few caps in parallel to get to ~20uF and call it a day. (I briefly felt like quite the clever used-to-be-an-engineer for remembering I could do that LOL... then I realized that these might be the wrong type of caps, period.)

Re: part numbers, yes I meant the caps. I can see the part near output is a "10nJ250" (not that I know what that means...) Curiously, the input cap looks like a ceramic - ergo the only one I wasn't worried about. The 22uF near the fuzz pot looks different; I assume that's electrolytic?

@huntingtonaudio - Please let me know if you mind my re-posting your images like this, and I'll pull them down.

 

[huntingtonaudio]

I don't mind you reposting this stuff at all. Cut, paste, hack, and share away, my friend.

Also, I sent you an email a few mintues ago when I saw your post. If you want to take 5-10 minutes for a video chat, I'll send you a google meet invite. I'm sure I can help get you going with this quicker if we chat than if we've got to type it all out.

Otherwise, I don't know if I'll have time to sketch up diagrams and write out a coherent response before early next week...

 

[mbenigni]

I don't mind you reposting this stuff at all. Cut, paste, hack, and share away, my friend.

Also, I sent you an email a few mintues ago when I saw your post. If you want to take 5-10 minutes for a video chat, I'll send you a google meet invite. I'm sure I can help get you going with this quicker if we chat than if we've got to type it all out.

Otherwise, I don't know if I'll have time to sketch up diagrams and write out a coherent response before early next week...

That is very generous, Seth! I just wrote you back. We can chat if it's still convenient for you. Otherwise, this can absolutely wait a few days.

 

[SillyOctpuss]

Thanks for this! I ordered a bzillion capacitors thinking I'd wind up with everything I needed forever LOL...

EEEEE 30 value 300 pcs Multilayer Monolithic Ceramic Capacitor assortment kit 10pf－10uF Individual Box Lid pf nf uf (300 pcs)

...but I didn't account for anything besides capacitance. Even then, I overlooked the fact that this assortment doesn't include the 22uF cap required between the Fuzz pot and ground. I figured I'd just wire a few caps in parallel to get to ~20uF and call it a day. (I briefly felt like quite the clever used-to-be-an-engineer for remembering I could do that LOL... then I realized that these might be the wrong type of caps, period.)

Re: part numbers, yes I meant the caps. I can see the part near output is a "10nJ250" (not that I know what that means...) Curiously, the input cap looks like a ceramic - ergo the only one I wasn't worried about. The 22uF near the fuzz pot looks different; I assume that's electrolytic?

View attachment 25192

@huntingtonaudio - Please let me know if you mind my re-posting your images like this, and I'll pull them down.

Yeah I bought a big kit when I started too, thinking it would keep me going for ages but I never really used any of it. I either didn't have the values I needed or they were physically too big for the boards I was using.

I just started ordering per project I was working on and then as I became more addicted started ordering 50-100 of each part at a time so I'd have loads of extras, plus it works out cheaper in the long run.

10nJ250 = 10n is the value, J means it's a 5% tolerance part and 250 is the voltage it's rated for.

This is basically the criteria I use for parts.

Resistors
1/4 watt metal film unless a build doc specifically requests something which will handle higher voltage.

Caps
Box film caps for values from 1nf up to 2.2uf. Anything 63v or 100v should be about the right size, Wima MKS2s are a good place to start.

Ceramic or MLCC for anything in the pf range. Always try to get CG0 or NP0 they'll be listed as those. The other types might be a little cheaper but they'll be noisier and will drift with temp changes.

Electrolytic from 1uf up. Definitely check the sizes of these to make sure they'll fit on the pcb (diameter) and in your enclosure (height), it's really easy to buy massive bastards you'll never use. 50/100v parts will usually keep you close to the right size. I usually buy Panasonic or nichicon, they're good reliable brands. A lot of builders will say it doesn't matter but I always use audio grade caps in the signal path and any standard electro which meets tbe right value and voltage in the power section.

Tantalum caps can be pretty decent in the audio path and can be had in the same values as electrolytics but I tend not to use them myself unless a build doc specifically calls for it.

Hopefully that helps a little bit. I can expand on anything you want tomorrow I need to get my kid ready for bed so had to fire it out quickly.

 

[mbenigni]

Yeah I bought a big kit when I started too, thinking it would keep me going for ages but I never really used any of it. I either didn't have the values I needed or they were physically too big for the boards I was using.

I just started ordering per project I was working on and then as I became more addicted started ordering 50-100 of each part at a time so I'd have loads of extras, plus it works out cheaper in the long run.

10nJ250 = 10n is the value, J means it's a 5% tolerance part and 250 is the voltage it's rated for.

This is basically the criteria I use for parts.

Resistors
1/4 watt metal film unless a build doc specifically requests something which will handle higher voltage.

Caps
Box film caps for values from 1nf up to 2.2uf. Anything 63v or 100v should be about the right size, Wima MKS2s are a good place to start.

Ceramic or MLCC for anything in the pf range. Always try to get CG0 or NP0 they'll be listed as those. The other types might be a little cheaper but they'll be noisier and will drift with temp changes.

Electrolytic from 1uf up. Definitely check the sizes of these to make sure they'll fit on the pcb (diameter) and in your enclosure (height), it's really easy to buy massive bastards you'll never use. 50/100v parts will usually keep you close to the right size. I usually buy Panasonic or nichicon, they're good reliable brands. A lot of builders will say it doesn't matter but I always use audio grade caps in the signal path and any standard electro which meets tbe right value and voltage in the power section.

Tantalum caps can be pretty decent in the audio path and can be had in the same values as electrolytics but I tend not to use them myself unless a build doc specifically calls for it.

Hopefully that helps a little bit. I can expand on anything you want tomorrow I need to get my kid ready for bed so had to fire it out quickly.

This is great information - thank you!

Of course, I will ignore a lot of it for my first build. I just want to get something/ anything working as proof of concept. If it passes signal, adds some gain, and doesn’t self-destruct, that’s a win state. I can work on subbing in more ideal parts to improve tone from there.

I’m sure I’ll be back with more questions. Many, many thanks to you and @huntingtonaudio!

 

[mbenigni]

Step 3: Don't panic... OK, maybe panic a little... No wait... IT'S ALIIIIIIVE!!!

When I first powered this up it was basically a hum generator, and I had to do some troubleshooting before I found my mistake(s). I didn't properly understand the pinout arrangement for the capacitors, and connected them such that both leads of each were on the same side of the circuit. I was just about to give up for the day when I figured that out, and... working fuzz! Very gratifying!

Seth at @huntingtonaudio has been tremendously helpful. I almost hesitate to describe this publicly because I don't see how he could possibly keep up this level of customer service long term. He answered all of my clueless emails (usually within minutes), set up a Google Meet to walk through all of my questions, and even sent additional parts when I was unsure about the most practical way to manage I/O. (One of those parts being the "breadboard butler" on the right, above. It's got guitar and oscilloscope I/O, a DC input jack, true bypass switching, and it mounts directly onto standard breadboards. So cool!) He's very enthusiastic about these products, and it's contagious! So anyway... thanks again!!!

Onward to step 4 - tuning the circuit and actually learning how it works. Right now it's a glorious sputtering mess... and completely unintentional. I think Fuzz Faces are going to be my hobby for a while. :)

 

[huntingtonaudio]

Seth at @huntingtonaudio has been tremendously helpful. I almost hesitate to describe this publicly because I don't see how he could possibly keep up this level of customer service long term. He answered all of my clueless emails (usually within minutes), set up a Google Meet to walk through all of my questions, and even sent additional parts when I was unsure about the most practical way to manage I/O. (One of those parts being the "breadboard butler" on the right, above. It's got guitar and oscilloscope I/O, a DC input jack, true bypass switching, and it mounts directly onto standard breadboards. So cool!) He's very enthusiastic about these products, and it's contagious! So anyway... thanks again!!!

Onward to step 4 - tuning the circuit and actually learning how it works. Right now it's a glorious sputtering mess... and completely unintentional. I think Fuzz Faces are going to be my hobby for a while. :)

Thank you for your kind words. It's awesome to see those boards all hooked up together so soon after you received them and to hear that you may be tinkering your way into a new hobby.

Next time you place an order for parts, (and I'll suggest Tayda Electronics as a first stop if you haven't tried them yet), throw a couple of these right angle, long pin pots of varying values in with your order.

They can screw directly into those screw terminals and keep you from having to solder little wires to your pots.

In fact I even think those short pinned pots you show in the picture might work as 'screw in' pots too, though not as ergonomically maybe as the right angle ones above.

Thanks again for circling back to share your positive experience. I appreciate it.

 

[mbenigni]

Thank you for your kind words. It's awesome to see those boards all hooked up together so soon after you received them and to hear that you may be tinkering your way into a new hobby.

Next time you place an order for parts, (and I'll suggest Tayda Electronics as a first stop if you haven't tried them yet), throw a couple of these right angle, long pin pots of varying values in with your order.
View attachment 25299
They can screw directly into those screw terminals and keep you from having to solder little wires to your pots.

In fact I even think those short pinned pots you show in the picture might work as 'screw in' pots too, though not as ergonomically maybe as the right angle ones above.

Thanks again for circling back to share your positive experience. I appreciate it.

Thanks for the reminder regarding the long pin right angle pots, Seth. Your instructions called this out as well, but I had trouble finding the right values in that format (in my extensive and creative search on Amazon LOL.) The ones I used came out of a very inexpensive assortment, but the legs are too short to lock into the brackets you provided. Between that and the entire extra breadboard just to fake a 22uF capacitor... I really made a mess of your design work. Will clean up ASAP.

This has been a very positive experience. I encourage anyone else who's curious to jump in!

 

[SillyOctpuss]

Nice one dude. It's a super addictive hobby and the fuzz face is a good circuit to get lost in for a while. You can do an awful lot with very few parts.

It's a pretty sweet feeling the first time you fire up a completed build and it sounds awesome through your amp.

Give me a shout if you want any help with a circuit or components.

 

[mbenigni]

Nice one dude. It's a super addictive hobby and the fuzz face is a good circuit to get lost in for a while. You can do an awful lot with very few parts.

It's a pretty sweet feeling the first time you fire up a completed build and it sounds awesome through your amp.

Give me a shout if you want any help with a circuit or components.

View attachment 25301

Thank you, @SillyOctpuss! Your feedback thus far has been a huge help.

 

[mbenigni]

Step 4: Play with it 'til you break it fix it.

I set the trimpots to the recommended values for a typical NPN fuzz face circuit. I actually preferred the sound of the circuit with the random (and much higher) values they were originally set to. But the next step is to do some reading and find out which direction to move these in order to achieve various characteristics intentionally.

I ordered some more potentiometers, footswitches, and 1/4" jacks (from Tayda, as recommended above) so I can start breadboarding different variations of the circuit, and clean this one up a little bit. I also wired it up without the Breadboard Butler, just to be sure I could, with 9V and audio I/O (via alligator clips) direct to the fuzz board. Then I broke the solder joint off one of the pots, and realized I should have been using the breadboard for those. And with simple breadboarding concepts like how to properly place components in parallel slowly coming back to me, I got rid of a mess of extra wires that were completely unnecessary. Having fun at least - the tinkering is seriously addictive.

 

[SillyOctpuss]

I set the trimpots to the recommended values for a typical NPN fuzz face circuit. I actually preferred the sound of the circuit with the random (and much higher) values they were originally set to. But the next step is to do some reading and find out which direction to move these in order to achieve various characteristics intentionally.

That's not a huge surprise. My favourite silicon fuzz face is the JHF1 and Q2 in that circuit is set to 5.75v instead of the normal 4.5v most people use.

The tonebender 1.5 is basically the same circuit with a few different values and it has a much higher voltage for Q2, anything up to 8v if I'm remembering correctly.

Analogman's sundial on the fuzz face let's you change the voltage on Q2 from approx 3v up to 7v.

 

[mbenigni]

That's not a huge surprise. My favourite silicon fuzz face is the JHF1 and Q2 in that circuit is set to 5.75v instead of the normal 4.5v most people use.

The tonebender 1.5 is basically the same circuit with a few different values and it has a much higher voltage for Q2, anything up to 8v if I'm remembering correctly.

Analogman's sundial on the fuzz face let's you change the voltage on Q2 from approx 3v up to 7v.

Good points of reference - thank you!

 

[mbenigni]

@huntingtonaudio, if you happen to have any free time, I'd love to hear more about your Breadboard Butler. Have you discontinued this product altogether, or are you working on a new version? It's immensely useful, but it's a bit of a black box to me at the moment. This may eventually be a concern if I breadboard with this inline, and then try to downsize to equivalent effects in dedicated enclosures. I got the Fuzz Face Explorer Board working with and without the Breadboard Butler, but there are a lot of components on the latter whose purpose (and effect?) I don't really understand. A circuit diagram or general overview would be great. :)