Addicted to Fuzz!

[idsnowdog]

New builds:

• EHX LPB1 Clone - I failed to build a ZVEX SHO clone so I built an LPB1 instead. A nice dirty boost.
• Angora Fuzz - An NPN Si Fuzz Face clone. With BC108 in Q1 and 2N3053 in Q2. I call it the Angora Fuzz because it is the softest, warmest, and thickest fuzz I have heard. The secret is the 2N3053. It sounds a lot like a Ge but with more output. I added a Tube Screamer style asymmetric soft-clipping section with a white LED and Ge 1N34A diode for more warmth. If I turn down the fuzz and od up it's a wide-ranging overdrive. If I turn up the fuzz and the od down it's a fuzz.
• Malice Fuzz - An NPN Si Fuzz Face clone. With BC108 in Q1 and 2N2222 in Q2. The 2N2222 in Q2 sounds evil when driven hard so I added a hard clipping circuit. There's a multi-position switch with symmetric (Growl) clipping stage with two Si 1N914 diodes. An asymmetric (Dark) stage with a Ge 1N34A and a 1N5819 Schottky diode. An asymmetric (Smooth) stage with two Ge 1N34A diodes. It has an inductor for the tone circuit. More pedals should use inductors because you can get some vicious tones.
• Selenium Falcon - A hybrid three-transistor ToneBender MK.III clone. Q1 and Q2 are Ge 2N1377 transistors while Q3 is a Si 2N1132 transistor. Three stages of Ge transistors sound good but clarity suffers. I chose the Si 2N1132 since there was already plenty of gain in the first two stages and that's where 90% of the tone comes from. The last Si stage widened the frequency range without adding much extra gain. There's a multi-position switch with six single-diode hard clipping choices. These are UV LED, Ge 1N34A, Si 1N4148, Schottky 1N5819, Si FR38, and a Selenium rectifier. For the last six months wondering what a Selenium diode would sound like in a clipping circuit had kept me awake at night. The Selenium clipping diode sounds amazing! It is very harmonically rich and lively. I have an inductor with a bass-cut capacitor for the tone control. I couldn't find a gain control that sounds good because there's way more gain than a Fuzz Face. I wouldn't have thought that one more transistor would make much difference but luckily this is a very muscular, resonant, and high gain circuit even with the clipping stages added.
• *To be named later* - I have a PNP hybrid Mozrite Fuzzrite on the bench. This one has been perplexing! A Fuzzrite creates its "fuzz" by taking two identical gain stages and mixing them together to create phase cancellation, blocking distortion, and crossover distortion. Three things that you usually try to remove from a circuit. The result is a fuzz that sounds like a fistful of rusty razor blades. The problem is the normal tone-tweaking capacitor tricks don't work with a Fuzzrite. It's like backing a trailer. Left is right and right is left and what you're left with is the remainder of the two gain stages cancelling each other. So sustain is limited, the attack is vicious but the resonance sucks so palm muting doesn't sound good. I tried it with two Ge transistors but there was so much blocking distortion that there was no sustain and since the transistors I had a low HFE rating there was no energy to create anything other than high frequencies. I tried two Si transistors but most of the Si transistors I have are higher HFE. Higher HFE gave better sustain and a wider frequency range but excessive high-frequency noise. I settled on a hybrid design with Si in Q1 and Ge in Q2. Early on I couldn't make the mix pot work due to a defective pot. So I just tapped the output from either the first or second transistor. The funny thing is when taking the output from either of the transistors I get an 80/20 mix either way that sounds good. So instead of using a normal pot for the mix I'm using a blend pot. The blend pot gives a wider usable tonal range. I have a wider variety of PNP transistors than when I started so I will need to test more combinations. I suspect I will need to pay more attention to biasing to reduce noise and increase output since the tone seems to be determined more by energy than voicing with capacitors.

[Mincer]

I have to admit, I haven't explored fuzz pedals all that much. I have an Expandora which I really like, but I never got on with more traditional fuzz pedals.

[jeremy]

very cool pedals!

[idsnowdog]

Introducing the Skuzzrite Fuzz. Quite a few things have changed. I installed SIP sockets for the transistors so I could try new configurations. There's a MMPSU56 Si PNP transistor in Q1. It has an HFE of 270 a big bass response and low noise. Q2 has a 2N1377 Ge PNP transistor with a flatter and wider frequency range than my other Germaniums. It has an HFE of 170. Choosing transistors with a wider frequency range, lower HFE, and lower noise paid off. Surprisingly biasing the transistors was simple. The nasty thin nasal tone and hiss are gone and the frequency range is much wider. The tone is like a fat sleazy tenor saxophone. I removed the balance pot and changed back to the 300K mixing pot which now has a wide range of usable tones. I added a tone control that trims bass one direction and treble in the other. I also added a three-diode hard clipping section with a pot to the output stage for a bit more hair. I have a 300HZ high pass filter on it so it doesn't muddy up the bass response. The original Fuzzrite had a 22K resistor from the depth pot to ground that works as a high pass filter. I found the 22K castrated an already nasty-sounding fuzz in my first version so I skipped it. I now have a 33K resistor on a switch instead. Larger value resistors cut less bass and volume. I may go to 47K because some places on the depth knob are thin and weak when it's in the circuit.

[jeremy]

so depth is what? i assume the clip controls the diodes?

[idsnowdog]

so depth is what? i assume the clip controls the diodes?

The depth control is weird and there's nothing else like it. It is a fuzz/tone control. It is labeled fuzz in this schematic. It controls the amount of transistor clipping by mixing the two transistors. Far left and right are fat/hot and in the middle, it's thin/bright. I'm not sure how it works. I believe it's unique for a good reason because it isn't that useful. The clipping control brings in the hard clipping diodes.

[idsnowdog]

This guy built a faithful replica of a Fuzzrite. Mine is far more refined and versatile. The resonance still sucks though and I'm not sure that can be tweaked.

[idsnowdog]

Introducing the Fat Bastard (left) and The Creamery (right):

• The Fat Bastard is a modified Bazz Fuss circuit voiced for guitar. Instead of an MPSA13, it has a BC517 transistor. The MPSA13 has better clarity but the BC517 has more gain. It has a UV LED soft clipper, a Silicon SF38 hard clipper, and an inductor tone circuit. The controls are volume, gain, and EQ. This a fat, loud, and brutal pedal.
• The Creamery is a modified Electra Distortion circuit. The layouts on the Internet have a few wrong values and are missing a critical resistor before the clipping section like the MXR Distortion+ and DOD 250. Without it, the clipping diodes don't get enough juice to work properly. I went with a NOS Germanium 2N2000 PNP transistor in Q1. Q1 alone has a nice warm overdrive but I added an ON/OFF/ON switch to choose between an Orange LED or SF38 diode in a soft clipping circuit. Since I didn't catch the missing resistor early on I decided to build a second gain stage with a Germanium 2N414 PNP transistor in Q2 that drives a DOD 250 style asymmetric hard clipping circuit with two Germanium 1N34s and one Silicon 1N916. The controls are 1st stage gain and 2nd stage gain, and tone with no volume. This is a very warm, thick, and creamy-sounding pedal with tons of Germanium character. I also experimented with a very Tweedy sounding JFET 2nd stage but since the polarity was opposite of the PNPs it will have to wait for another pedal.

[jeremy]

how can i get a fuzzface to cut through a band better but still react like a ff? im almost to the point of ordering an empress para eq, which wouldnt suck, but they arent cheap

[idsnowdog]

how can i get a fuzzface to cut through a band better but still react like a ff? im almost to the point of ordering an empress para eq, which wouldnt suck, but they arent cheap

You can easily increase your volume by swapping the position of the two bias resistors on Q2. The bias point for the transistor doesn't change but the volume increase is substantial. The tone doesn't change either.

The input and output capacitors have a lot of influence on the tone. A lot of energy is wasted amplifying high and low frequencies that nobody can hear. You can put a small value pF capacitor around the Q1 or Q2 collector bias resistors to cut high frequencies because anything above 8khz is noise. The amount of EMI/RFI in the circuit will drop considerably and clarity will improve. Silver mica caps sweeten treble response and you can also try ceramic, or poly caps to fine-tune.

The input capacitor lets a lot of bass into the circuit. Choosing a smaller value capacitor tightens up the bass response, improves clarity, and increases volume because the circuit isn't wasting energy amplifying signals below 60hz. You can also tune your bass response by changing the output capacitor. However, changing the input capacitor is the most effective and there's nothing wrong with the stock output capacitor value. You can use a three-way switch to give you different input capacitors to compliment your pick-up types like single coil and humbuckers.

The bypass capacitor on the emitter is too large. This is analogous to a cathode bypass capacitor on a tube amplifier and 20uF dips too far into the bass. Try a 15uF or 10uF to filter out bass and your gain pot will clean up better. You can expand the frequency range and get a wider gain range using a higher-value pot like 2K. The stock 1K pot muffles too much.

I use this frequency generator to determine what frequencies to cut/boost. https://onlinetonegenerator.com/ . Once I know the frequencies I go to this site to determine which capacitors to use for high/low pass filters. https://www.digikey.com/en/resources...gh-pass-filter . I measure the resistance where I will place the capacitor first and then put in the frequency where I want the high/low pass filter to start and it will give me the capacitor value.

https://www.electrosmash.com/fuzz-face