Andy's Simple Fuzztone !

[cheezit]

Just breadboarded it, but with a different NPN transistor, since i didn't have one of the listed one.  I used a PN2369A for the NPN spot, and 2N3906 for the PNP spot.  The PN2369A has an HFE of 58 or so.  I put a 1M pot at the end for a volume control, and a 0.22 orange drop for the input cap.

The result?  A low/medium-gain fuzz/boost with a lot of volume---it'd be pretty unusable without the 1M pot.  But it has a nice really vibe and touch-sensitive grit, and drives other pedals well.

I tried popping out the 1k resistor between collector1 and base2 and replacing it with a jumper to boost the gain, but it just made the sound kind of spitty and raspy---in a cool, broken, kind of way, but it didn't improve matters.

I'm going to try out a higher-HFE NPN transistor.  Given the nice sounds at lower gain I may try either a pregain control or replacing the 1k with a 10k or 50k pot wired as a variable resistor.

[Steben]

Do we need the 470k in front of Q1?
AFAIK, the base-collector sets it's own bias if no emitter resistor is there.

[Dragonfly]

Do we need the 470k in front of Q1?
AFAIK, the base-collector sets it's own bias if no emitter resistor is there.

Need ?

No.

But it does stabilze it better, and, at least on the breadboard provided a bit less noise.

and LPB-1 doesnt "need" the 47k either, but we still use it 

[Dragonfly]

Just breadboarded it, but with a different NPN transistor, since i didn't have one of the listed one.  I used a PN2369A for the NPN spot, and 2N3906 for the PNP spot.  The PN2369A has an HFE of 58 or so.  I put a 1M pot at the end for a volume control, and a 0.22 orange drop for the input cap.

The result?  A low/medium-gain fuzz/boost with a lot of volume---it'd be pretty unusable without the 1M pot.  But it has a nice really vibe and touch-sensitive grit, and drives other pedals well.

I tried popping out the 1k resistor between collector1 and base2 and replacing it with a jumper to boost the gain, but it just made the sound kind of spitty and raspy---in a cool, broken, kind of way, but it didn't improve matters.

I'm going to try out a higher-HFE NPN transistor.  Given the nice sounds at lower gain I may try either a pregain control or replacing the 1k with a 10k or 50k pot wired as a variable resistor.

thanks for the report.

i had thought about a pregain, but opted for simplicity.

did you try diodes to ground at the end as i mentioned, kinda like a simplified Bosstone ?

[DougH]

Okay Kids- sung to the tune of "Runnin' with the Devil":


My simple fuzztone

Wasn't so simple...

When I posted it

On the board...


Haha! Sorry Andy...

I'll stick this in the circuit simulator and see what comes out the other side... 

[cheezit]

thanks for the report.

i had thought about a pregain, but opted for simplicity.

did you try diodes to ground at the end as i mentioned, kinda like a simplified Bosstone ?

Nope, I'll try that tonight.  This circuit definitely has enough gain to create some square-waye action.   I'm not usually big into the diode clipping sound unless there's a lot of filtering involved, so we'll see.

[DougH]

Okay, I ran this in the circuit simulator and it looks like it should work great.

Q1: 2n2222, Q2: 2n2904. Both collectors sit at around 3v or so. The output of Q1 is pretty squarish looking already. Overall it has gain of around 46db, which is about 6db or so hotter than the Sam Ash fuzz. Depending on your amp, it may drive the amp a little, so an output volume control is probably not a bad idea. Any of these circuits with a grounded emitter will be vulnerable to bias drift due to temperature. However, according to Simetrix, temperature swings of +-20 degrees will cause Q2 collector voltage drift of .3v. Take that with as many grains of salt as you wish...

Overall, it looks like a nice little fuzz that should work fine as shown on the schematic.

[cheezit]

Just breadboarded it, but with a different NPN transistor, since i didn't have one of the listed one.  I used a PN2369A for the NPN spot, and 2N3906 for the PNP spot.  The PN2369A has an HFE of 58 or so.  I put a 1M pot at the end for a volume control, and a 0.22 orange drop for the input cap.

The result?  A low/medium-gain fuzz/boost with a lot of volume---it'd be pretty unusable without the 1M pot.  But it has a nice really vibe and touch-sensitive grit, and drives other pedals well.

I tried popping out the 1k resistor between collector1 and base2 and replacing it with a jumper to boost the gain, but it just made the sound kind of spitty and raspy---in a cool, broken, kind of way, but it didn't improve matters.

I'm going to try out a higher-HFE NPN transistor.  Given the nice sounds at lower gain I may try either a pregain control or replacing the 1k with a 10k or 50k pot wired as a variable resistor.

In case it wasn't clear from the above, my build is massively loud, which is consistent with some of the troubles other folks have been having.  Since I am using a lower gain transistor in the first stage, I expect that if I sub in one of the suggested higher-gain transistors it will still be loud and likely louder.  I just happened to put a volume pot on the end of it, so it is usable for me. 

But it does sound as though dragonfly's build and mine are behaving differently in that regard.

[Solidhex]

Yo

  Breadboarded it last night. Worked great right off the bat. 2n222 in Q1, 2n2907 in Q2. Tried some different caps in the. Right now I have a 1uf input, .1uf output. Sounds great! Has balls and a nice texture. Gross! let me rephrase that. Has a nice low end grunt and nice detail in the fuzz sound. Cleans up well with the volume control. Great candidate for a pre gain control.

--Brad

[slideman82]

Anybody tried with Ge? Where are GE fans?

[Gus]

If you have a signal generator and a scope set the generator to triangle wave output at about 100mv into the circuit  and look at the waveform out.  Also look in the art of electronics about how the gain changes with input level.

[Zben3129]

Breadboarded with a 3904 and a 3906, sounds great.

Nice job Andy   

P.S. In addition to the low parts count, its the common values that really do it for me. Just by looking at the schem i knew right away that I had hundreds of all the resistors and caps in the exact values, didn't have to worry about finding say a 66k resistor or something like that. Keep it up!



Zach

[CoolJohnny]

ho-lee shee-at that thing sounds incredible!!! i'll have to breadboard it tomorrow. ive made some awesome pedals over the years, some of 'em that even took me years, but it seems like when it comes to overdrive/fuzz, the simpler the better. i'm a rabid bazz fuss fanatic (i've built at least six variants for myself and friends) so this could be right up my ally. thanks to the info from everyone who has already tried it.

[cheezit]

thanks for the report.

i had thought about a pregain, but opted for simplicity.

did you try diodes to ground at the end as i mentioned, kinda like a simplified Bosstone ?

Nope, I'll try that tonight.  This circuit definitely has enough gain to create some square-waye action.   I'm not usually big into the diode clipping sound unless there's a lot of filtering involved, so we'll see.

I tried the diodes---didn't work out.  I used some red LEDs.  Putting them before the 1uf output cap just made horrible spitty gated sounds, and after the cap didn't do anything appreciable.  Tried a couple of other spots with no nice effects.  Only one of the LEDs lit up very much---I wonder if perhaps the output signal before the cap is biased fairly close to the 9v rail?  I haven't checked with a MM.

[Dragonfly]

Cool - I'm glad you guys were able to verify it...and thanks for the sim, Doug...I appreciate it !

I'm not going crazy ! I was worried that it was only working for me, and that my ears (and the meters) were lying to me !

[Dragonfly]

thanks for the report.

i had thought about a pregain, but opted for simplicity.

did you try diodes to ground at the end as i mentioned, kinda like a simplified Bosstone ?

Nope, I'll try that tonight.  This circuit definitely has enough gain to create some square-waye action.   I'm not usually big into the diode clipping sound unless there's a lot of filtering involved, so we'll see.

I tried the diodes---didn't work out.  I used some red LEDs.  Putting them before the 1uf output cap just made horrible spitty gated sounds, and after the cap didn't do anything appreciable.  Tried a couple of other spots with no nice effects.  Only one of the LEDs lit up very much---I wonder if perhaps the output signal before the cap is biased fairly close to the 9v rail?  I haven't checked with a MM.

cool - i put 1n914s to ground after the cap, and it brought down the output level and compressed it slightly, but didn't add too much to the sound...though it might be better on a big amp.

[Dragonfly]

Breadboarded with a 3904 and a 3906, sounds great.

Nice job Andy   

P.S. In addition to the low parts count, its the common values that really do it for me. Just by looking at the schem i knew right away that I had hundreds of all the resistors and caps in the exact values, didn't have to worry about finding say a 66k resistor or something like that. Keep it up!



Zach

glad you like the sound

i try to avoid weird values for the most part. you can literally walk into radio shack and find all the parts needed for this build, except for the footswitch.

[Dragonfly]

Yo

  Breadboarded it last night. Worked great right off the bat. 2n222 in Q1, 2n2907 in Q2. Tried some different caps in the. Right now I have a 1uf input, .1uf output. Sounds great! Has balls and a nice texture. Gross! let me rephrase that. Has a nice low end grunt and nice detail in the fuzz sound. Cleans up well with the volume control. Great candidate for a pre gain control.

--Brad

nice... somehow i knew you'd dig the rawness of it !

such a simple circuit...but a cool tone that doesnt sound like most fuzzes !

i have a few mods i want to talk to you about. my cell is down, but i'll call you in the next couple days....

[Dragonfly]

ho-lee shee-at that thing sounds incredible!!! i'll have to breadboard it tomorrow. ive made some awesome pedals over the years, some of 'em that even took me years, but it seems like when it comes to overdrive/fuzz, the simpler the better. i'm a rabid bazz fuss fanatic (i've built at least six variants for myself and friends) so this could be right up my ally. thanks to the info from everyone who has already tried it.

thanks ! I hope you dig it !

bazz fuss is a great circuit...an all time classic !

[Dragonfly]

If you have a signal generator and a scope set the generator to triangle wave output at about 100mv into the circuit  and look at the waveform out.  Also look in the art of electronics about how the gain changes with input level.

i need to get some "hi tech" tools...   

i wish i had the $$$ and space for a scope, generator, etc....