Fuzz Face Clone Issues

[TheLeakeyWeasel]

Please say hi to the NOOB!  This is my first post, my first build, my first pedal!  

I'm starting out and decided a fuzz face clone could be a simple enough intro to peal building.  I have the circuit breadboarded for testing.  The jacks and 3pdt switch are currently installed in the housing just for stability.  I have all the wires long for the time being so I can run into the breadboard for testing.  I'm using the original fuzz face clone schematic for the Dallas-Arbiter pedal.

http://fuzzcentral.ssguitar.com/fuzzface.php

The schematic is the first on the page.

I have two 2N404A transistors, a 22uF resistor at the fuzz pot (the parts list called for it and not a 20uF?).  I have a 10k trim pot in place of the 8.2k resistor as suggested by the build plans on the page (maybe I misunderstood what was being done?), I figure a variable resistance would be fine.  I also threw in a 100k pot for the fuzz instead of a 1k.  I understand there is a large difference there in value. I figured I'd throw it in there because I had it handy at the time and not a 1k.  I still need to pick that up.  When looking at the board layout for the build at the bottom of the page the OP also has a 100uF capacitor in the mix as well.  The board layout left me a bit puzzled as there's no schematic for what he built, just the schematics listed for the original Germanium, Silicon, and reissues.  Therefore I dropped the 100uF capacitor and just followed the original schematic as I rolled it out on the breadboard

I tested the 9 volt and it's showing 8.2 volts.  I have the circuit working.  The issue is the horrible odd sound I get.  It's like fuzz in the worst way possible.  If the fuzz pot is rolled back it will clear up to something respectable, but it still has harsh harmonics.  The other thing going on is the sound has this odd delay with the attack of each note.  The sound will fade in quickly and then fade out and fizzle.  I will be getting a 1k pot.  

Are the transistors bad or is it just my inexperience....or both?  Thanks for your input.

[nocentelli]

It definitely won't work with a 100k fuzz pot: Close to 1k is needed to bias the transistor correctly. Replace the way-out-of-spec fuzz pot with a 1k fixed resistor (if you have one) and put the 22uF cap in parallel with this resistor. This should give you the fuzzface sound with the fuzz pot maxed out. If it doesn't work like that, you've got other problems as well.

[TheLeakeyWeasel]

Will do.  Thanks for the advice.  Will keep at it.   

[Kesh]

100uF power supply filtering capacitor and a 1N4001 reverse polarity protection diode are kind of standard add ons to every pedal to cope with people getting batteries and power jacks the wrong way, and to help clean up noise from a power supply.

They don't change the circuit.

Like nocentelli said, 100k is way off, 1k or 2k only there. Or sub in a 1k fixed resistor and have the 47u cap parallel to it, attached directly to the transistor's emitter, and use your guitar's volume to control fuzz.

[TheLeakeyWeasel]

I ordered 500k pots for my strats and also the 1k for the pedal.  I just got done with the first go and yeah, that did the trick.  Now it's on to fine tweaking and taking a look at some fuzz mods to see what I can and want to do to make this sound perfect.  Thanks again for your time and your answers!

[LucifersTrip]

excellent

next....only way to continue is with voltage readings.  I've built a load of fuzzes and it's still a necessity.

on the other forum, someone was cool enough to save all the voltages of good sounding ge ones that builders reported and then averaged them:

q1e: 0
q1b: 0.1    
q1c: 0.578  

q2e: 0.447
q2b: 0.578  
q2c: 4.51

good luck...

[TheLeakeyWeasel]

This is the first time I've ever done this so please excuse my new guy questions.  Where am I putting the leads when testing the voltages?

If voltages are too high or too low what is done to correct any issues?

[TheLeakeyWeasel]

Q1E:   0
Q1B:   0.12
Q1C:   0.44

Q2E:   0.32
Q2B:   0.45
Q2C:   4.48


I was getting a bit over 8 on Q2C with the 10k trim pot.  I replaced it with a 10k resistor and it straightened right out.  Is there any need for any more tweeking or should I leave this exactly as it is?

[LucifersTrip]

I was getting a bit over 8 on Q2C with the 10k trim pot.  I replaced it with a 10k resistor and it straightened right out.  Is there any need for any more tweeking or should I leave this exactly as it is?

Not if you like the sound you have!   ....especially if you're able to hit around 4.5 - 5V with a ~ 4-15K on Q2C. if you have to go too far out of that range for 4.5 - 5V, then best to try different transistor(s)

but, maybe you'll like the tone at 6V the best like pinkjimi. Play through it for a while at voltages from 4 - 7V and see what like.

Remember, a very common "mod" is lowering the 500K vol to 250K to make it a little "sharper". If you want to consider that, simply put another 500K pot across the outer lugs of the volume pot (500 // 500 = 250), then slowly turn it down till you like it best....and sub a fixed resistor.

good luck

[TheLeakeyWeasel]

Thanks for the advice!  I liked it at the 8V with the 10k trim pot, but I'm eager to try it now with the 10k resistor that's giving me 4.4V.  I'll definitely have to play around a bit to find out exactly where I like it.  I would like to get a bit more top end out of it.  I have to say I got some great growl from it, but definitely want to see what happens with a little more top end. 

[pinkjimiphoton]

excellent

next....only way to continue is with voltage readings.  I've built a load of fuzzes and it's still a necessity.

on the other forum, someone was cool enough to save all the voltages of good sounding ge ones that builders reported and then averaged them:

q1e: 0
q1b: 0.1    
q1c: 0.578  

q2e: 0.447
q2b: 0.578  
q2c: 4.51

good luck...

listen to this guy, noob, he knows his fuzz.

[pinkjimiphoton]

I was getting a bit over 8 on Q2C with the 10k trim pot.  I replaced it with a 10k resistor and it straightened right out.  Is there any need for any more tweeking or should I leave this exactly as it is?

Not if you like the sound you have!   ....especially if you're able to hit around 4.5 - 5V with a ~ 4-15K on Q2C. if you have to go too far out of that range for 4.5 - 5V, then best to try different transistor(s)

but, maybe you'll like the tone at 6V the best like pinkjimi. Play through it for a while at voltages from 4 - 7V and see what like.

Remember, a very common "mod" is lowering the 500K vol to 250K to make it a little "sharper". If you want to consider that, simply put another 500K pot across the outer lugs of the volume pot (500 // 500 = 250), then slowly turn it down till you like it best....and sub a fixed resistor.

good luck

and welcome to the forum!

the 2n404's may be a little bit hot for the circuit depending on what YOU like.

as my esteemed brother lucifer's trip says, i tend to like it biased a little bit cleaner so it's more responsive to my guitar's volume control.
that way, with the fuzz pot cranked, i can get wooly, phat-assed walls of filthy compressed fuzzy hellacious goodness, and turn it down from there thru pretty much every classic guitar sound you've ever heard to CLEANER than when the fuzz is OFF.

welcome to the fold, man!! if you likes fuzz, you're gonna love it around these parts.

it takes some serious nut to take on a fuzzface as a first build and get it to work. they are notoriously finicky circuits!!

you may wanna google up "britface" for a mod that you may find worth doing...a ge diode in parallel between base and emitter with the cathode (band) going to the emitter of q1. it MUST be a germanium diode.

it will help with temperature stability issues a bit. depending on your climate, it may or may not be a big deal. here in connecticut, fuhgeddaboudit. the weather changes so often, the thing needed the bias pot moved to an external control. when it's real hot...you get thermal runaway, the gain goes wicked high, and it stops working. when it gets real cold...the gain keeps dropping til it gets blatty farty and...you guessed it...don't work at all.

somedays they sound great. some days they don't. somedays they sound AWESOME. some days they just sit there and smile at you like a plate of sunny side up eggs.

your eggs will smile at you if you mess with a fuzzface long enough. i know it sounds crazy, but it's true.



if ya can't find the britface thing, let me know and i'll up it for you.

[TheLeakeyWeasel]

Thank you guys for the warm welcome.  I'll keep the britface option open.  As of right now I'm totally happy with the face as it stands.  I tried both a 10k trim pot and then a straight 10k reisistor.  The trim gave me 8 volts off the Q2 emitter while the 10k resistor gave me 4.4 volts.  I still have the circuit bread boarded to test.  So swapping back and forth I have to say I definitely like the sound of 4.4 volts.  Next  I replaced the 500k pot with a 250k like it was suggested and I got more high end and it sounded loads clearer all around.  I have to say I've fallen in love with the 250k pot. 

I was watching a demo of the Bonomassa fuzz face compared to the Eric Johnson fuzz face.

http://www.youtube.com/watch?v=-_Z8SAw_JPQ

With the 250k pot and 4.4 volt on Q2E I'm getting more of a Bonomassa fuzz tone out of my pedal.  The 8 volts and 500k pot was definitely giving me more of an Eric Johnson fuzz tone.  Now it's on to mounting it into an enclosure.  I have a temp enclosure until I can do a permanent enclosure with a 60's psychedelic paint job.  I can't wait to take this thing for a spin at practice this week.  I'm like a kid in a candy store.

The main thing is I have no understanding about circuits and the engineering aspects that would help me understand how it works and why it works.  All I did for this build was get a schematic, parts, and make it happen.  I had no clue what a bread board was until 2 weeks ago or so.  So much to learn but wanting to learn it ALL AT ONCE! 

[Pyr0]

When you had the trim pot in did you try adjusting it ?  The trimmer is just a variable resistor, and should be adjustable from 0 to 10k, It looks like you might have had it positioned close to the 0 end, you should be able to adjust it up to 10k and get the same results as with your 10k resistor + a range of voltages inbetween.

[TheLeakeyWeasel]

Yeah.  The lowest I could get it to drop was to the low 7's.  I couldn't understand how the trim pot wouldn't drop any more.  It made no sense in my mind that the 10k trimpot  gave me double the voltage no matter how I turned it as opposed to a 10k resistor. 

[pinkjimiphoton]

if you tied one leg to the wiper, the trimmer will only go down half way. make sure that + voltage goes to one side, and the voltage comes out the middle...use it as a variable resistor and you can turn it up or down all the way. tieing the third leg to the wiper is a failsafe, so that the pot can't be turned all the way down and damage something.

hit geofex.com, and (or google) look up "the technology of the fuzzface " by our Resident Guru, and you WILL understand how and why a face works.

btw...if you want it a little brighter still, you can go to a 100k output pot. that will take a bit more of the "wool" off, i do it on some of my pedals if they seem to woofy for someone.

you're on your way, dude. you got one of the simplest..yet hardest...circuits working and under your belt!! congrats!!

[TheLeakeyWeasel]

I have read through the technology of the fuzzface.  I actually have it book marked for reference.  I don't have it completely under my belt yet.  I just committed the circuit to perf-board and of course....NADA!  It sounded like a million bucks in the bread board  hahahaha.  I broke out the old DMM and checked my resistors.  The 470 is reading ZILCH.  I'm thinking I may have fried it during soldering.  My first attempt at soldering on the old perf and I was trying to make a solder bridge.  I noticed that the resistor was pretty darn hot and stopped to let it cool down.  I guess the damage was done.  Everything else seems to be good to go.  I've gone over the circuit and soldered connections and all connections are as they should be.  Battery is good.  I can only find the 470 resistor giving me a reading of zero.  Little by little I'm getting there.

[LucifersTrip]

hey....

if you tied one leg to the wiper, the trimmer will only go down half way.

gotta ask you what you mean by this, so as not to confuse the OP. If you tie one leg to the wiper, you will still be able to turn it all the way down. If you have 10K, you will still have the full sweep from 0 - 10K

tieing the third leg to the wiper is a failsafe, so that the pot can't be turned all the way down and damage something.

believe it or not, it's actually kind of the opposite. The reason you tie a lug to the wiper is so that if the wiper fails, there will still  be resistance. You won't have an open connection even after failure.

[LucifersTrip]

I just committed the circuit to perf-board and of course....NADA! 

hopefully, you didn't make beginner mistake #1.

The first thing you do after getting a circuit to work the way you want it is to measure & record voltages, so you always have a reference.

If it fails after soldering, you can always look at the voltages measured during failure to help you pinpoint the problem.

good luck

[TheLeakeyWeasel]

Of course I made beginner mistake #1.  Planning?  Who does that?  These things are like the internet.  It all runs on fairy dust and unicorn farts.  Magic and happiness.  Nothing can go wrong with any of this.     I'll get it right eventually even if I have to order all new parts and another board.  At least now I know circuit from front to back now.  That's something I never thought I would be able to say.