This feature of giving soft asymmetric distortion to small signals and clipping harder in both semi-cycles on big input signals (strong chords) gives a nice touch sensitivity which enhances the expressive possibilities. This is due to the C, The graph also shows a general roll off of the bass harmonics under 14Hz, this is due to the high pass filter created by C, Broadly speaking the frequency response of the Fuzz Face is not very innovative, it just removes some bass and keeps all the highs which contribute to have powerful distortion. Quick View. 4.2 Voltage Total Gain. (Pedal must be powered on). The circuit is a simple 2 stage amplifier with a feedback network path. As a rule of thumb with more feedback, there is less global gain, following  the formula: \[\\A_{FB}=\frac{A_{OL}}{1+B_{FB}A_{OL}}\]. Again, an 80 to 90-ish silicon device will work for Q1 if you re-bias using a 10K pot or trimpot in place of the Darlington's Collector load. When the gain goes high the feedback is smaller and the high pass filter influence is less important. In this case, the total voltage gain measured at Q, In the above image, the output voltage at Q, It might look funny but It has a reason: the output signal is not much larger than the input signal to keep the huge amount of signal available from over-driving the input of the pedal or amplifier following it. It produces a characteristic high distorted sound called. Fuzz Face Circuit. The internal series resistance of the battery is added to the 470Ω R3 resistor, modifying the value by a significant amount. This divider reduces the gain by a factor of R2/(R2+R3) = 470/(470+8K2) = 0.054 (-25dB), so the real gain of the output stage is: GVTOTAL = GVPEDAL - Attenuation of R2/(R2+R3)= 19.5 - 25 = -5.5dB. The earliest models were covered in red, light or dark gray Hammerite paint with the Fuzz Face logo in white or black, the text in the smile reveals the pedal's age. Want to reduce the input voltage so the pedal breaks up into oscillation? Fuzz Face Original Version (PNP) Components To use a PNP Fuzz Face with a normal 9V power supply, you need to include the power inverter section which is C1, C8, C9, D1 and IC1 which is generates the -9V required. Broadly speaking the frequency response of the Fuzz Face is not very innovative, it just removes some bass and keeps all the highs which contribute to have powerful distortion. So, like all Deep Trip pedals, the BOG takes the usual 9V, center negative power supply, as most standard pedals do. The Fuzz Face Models. Proper biasing of the Germanium transistors found in Synthrotek’s Fuzz Face clone and the Face the Fuzz pedals is essential to getting the best (optimal) tone out of your product. The 20uF is so big that almost all the frequencies get full amplification. There are two main possibilities: Germanium transistors are considered to have an overall better sounding to this effect with some drawbacks: germanium manufacturing is not as consistent and controlled as silicon and they have shorter lifespan and more temperature sensitivity. The Vox ToneBender arrived at a similar time to the Arbiter Fuzz Face (production spanned from 1966-68), and was most likely based on the Tonebender MK1.5. My sincere appreciation for D.Clark support. The fuzz face output impedance is affected by the feedback network and has a real value of 15KΩ (measured at 1KHz with RVOL=500KΩ). No hassles here, no exclusive power supply, no polarity inversion needed, plain simple. Fuzz Face: This is the classic Fuzz made famous by Hendrix and others. I think the Arbiter-England one didn’t use the NKT275 germanium transistor; in those days we used the AC128. addy0bbee1a085a5092a78cb1fa82c758b68 = addy0bbee1a085a5092a78cb1fa82c758b68 + 'electrosmash' + '.' + 'com'; Fuzz Face Frequency Response.7. In 1993 Dunlop took over the production selling the fuzz face in different flavors. These instructions should also help with other Fuzz Face clones as well. The relationship between feedback and gain is explained in the Feedback Network Section. It's the "middle" voltage, the spot where a waveform is centered on. PIN-OUTS MP39 (viewed from below) GT308V Dot indicates Emitter E B C Middle leg is Collector The voltage required is 4.5v. You can read more about it in the Frequency Response section. Silver Supporting Member. This information is for those seeking precision. The output stage is again a PNP Common Emitter Amplifier, this time with a variable emitter degeneration resistor (RFUZZ=1KΩ). Add to Wishlist. 4.3 Power Supply.5. Since both kits and completed pedals both come with bias tested transistors, you should not need to completely remove the electronics from the housing. [clarification needed] The original instructions even described the Fuzz Face as a "Tone-Bending" unit. In this video I will set the trimpots of my Dunlop Fuzz Face JDF2Hope you find it useful The plot below represents the total frequency response of the fuzz face, the different lines show the effect of the volume potentiometer. , you are free to copy, share, remix and use all material. I’m not looking to copy a specific sound, just to use something for original music not to copy other people’s tone. In terms of design, the bypass capacitor C, All the frequencies over 8Hz get full amplification. and a high gain in the second stage (β=110-130 approx.). 8.1 Datasheets. Using a smaller resistor, the filter will cut more lows out (fc=160Hz) which will result in a brighter sound. In the image below the voltage gain of the input stage is shown varying the fuzz potentiometer. The effect became very popular because Jimi Hendrix played it and there were not many distortion pedals around at that time. The clipping begins softly for smaller signals (and gains) and then with the fuzz potentiometer action the clipping goes harder with harder playing. This single knob confines a great power, capable of delivering an incredible range of vintage fuzz tones. As the volume goes lower (blue line), the graph shows a steeper slope with more high content. Because the fuzz is so dependent on individual transistors there can be huge variation in the way these sound. Again.... All the lovely fuzzy goodness of the FF but with an external bias control. A guide to the best Fuzz Face pedals - a circuit that deserves to sit proudly on the fuzz pedal podium, offering a nuanced and dynamic sonic behavior at different gain levels. The cut frequency of this HPFilter is: \[fc=\frac{1}{2\pi R C}=\frac{1}{2\pi \cdot R_{vol}\cdot  C_{3}}=\frac{1}{2\pi \cdot 500K \cdot 0.01uF}= 31Hz\]. Go right ahead. The input stage will first hit mushy saturation on one polarity of signal and then if driven hard enough, hit cutoff on the other polarity. Fuzz Face Global Feedback Network.6. It can be broken down into three parts: The last block (the Feedback Network) will affect the rest of the analysis because it will influence the most important parameters: voltage gain, input impedance, output impedance and frequency response. We choose optimum gain for Q1 and Q2 to make sure that proper biasing is possible. Drives & Fuzz Kloned Centaur. In other pedals with similar input stages like the one in the Big Muff Pi a series resistor is placed at the input in order to higher the impedance (at the cost of creating a voltage divider that reduces the available input signal). var addy0bbee1a085a5092a78cb1fa82c758b68 = 'info' + '@'; In amplifier design the degenerative (negative) feedback is used to: The properties above are obtained at the expense of a reduction of gain. Making this cap bigger will let more low frequencies out. Post by DrNomis » 03 Jan 2014, 15:42. polifemo wrote:Messin' … Easiest To Use Fuzz Pedal. If they see a buffer at the input, they tend to sound awful. Don’t Forget to check the additional notes on the Tone stack Section . It can be calculated as: For this math calculation the feedback network is ignored but in practice, it will lower the input impedance to 5KΩ approx. You need JavaScript enabled to view it. setting bias on Eric Johnson fuzz face Discussion in 'The Effect effect' started by DEXTER74, Apr 23, 2013. 2.2 Fuzz Face Components Part List / Bill of Materials: This is the reduced list of components needed to build a Fuzz Face: 1    C1:    2.2 uF1    C2:    20 uF1    C3:    0.01 uF1    R1:    33KΩ1    R2:    470Ω1    R3:    8.KΩ1    R4:    100KΩ1    Rvol:    500KΩ (Audio tap)1    Rfuzz:    1KΩ (Linear tap)2    Q1, Q2:    AC128     Jack in, Jack out, battery clip, DPDT foot-switch. Also we included in this project a bias control, cause we all know how fun is to experiment with starving fuzzes! The main difference is that the Fuzz Face is biased slightly colder, making it more usable in warm environments. When the input signal has a higher level, the input stage will soft-saturate in both semi-cycles like in the image below. PsPice models used for AC128 Fuzz Face simulation: .MODEL GERPNP_LOWGAIN PNP(IS=85.8N BF=85.000 NF=1.000 VAF=102.207 +IKF=9.981M ISE=0.435N NE=1.200 BR=20.000 NR=1.000 VAR=20.000 +IKR=1.248M ISC=120.8N NC=1.200 RB=173.312 IRB=5.000U RBM=43.328 +RE=20.000 RC=60.000 CJE=6.000P VJE=0.400 MJE=0.400 TF=0.150U+XTF=9.996 VTF=2.000 ITF=9.983M PTF=1.000 CJC=3.750P+VJC=0.600 MJC=0.330 XCJC=0.650 TR=2.865U+CJS=0.0 VJS=0.700 MJS=0.500 XTB=1.000 EG=0.670+XTI=4.000 KF=5.000F AF=1.000 FC=0.750).END, .MODEL GERPNP_HIGHGAIN PNP(IS=120.8N BF=120.000 NF=1.000 VAF=102.207 +IKF=9.981M ISE=0.435N NE=1.200 BR=20.000 NR=1.000 VAR=20.000 +IKR=1.248M ISC=120.8N NC=1.200 RB=173.312 IRB=5.000U RBM=43.328 +RE=20.000 RC=60.000 CJE=6.000P VJE=0.400 MJE=0.400 TF=0.150U+XTF=9.996 VTF=2.000 ITF=9.983M PTF=1.000 CJC=3.750P+VJC=0.600 MJC=0.330 XCJC=0.650 TR=2.865U+CJS=0.0 VJS=0.700 MJS=0.500 XTB=1.000 EG=0.670+XTI=4.000 KF=5.000F AF=1.000 FC=0.750).END. Synthrotek is now testing and bias testing all of the Germanium transistors that we send with kits and completed units. Reduce nonlinear distortion: make the gain constant. document.getElementById('cloakc9796beda9bd2381890082165b7e7805').innerHTML = ''; 6 = 3dB) all frequencies below 14Hz will suffer an attenuation 6dB/oct. Ivor Arbiter took the round shaped enclosure idea from a microphone stand and it was the first pedal including a DPDT stomp-switch. The Fuzz Face circuit has 9 components. Capacitors present an impedance that decreases with frequency, the bias (DC) points will remain the same but high guitar (AC) signals will get higher voltage gain. The Fuzz Face Resistors: The original models use 1/2W carbon film resistors. Part of the output current is taken from Q2 emitter and introduced as current in Q1 base, so the feedback resistor R4 is shunt connected with the input and in series connected with the output. Image result for fuzz face bias pot. This information is for those seeking precision. Jack in, Jack out, battery clip, DPDT foot-switch. Rated 5.00 out of 5 € 9.90. It is not the ideal input stage for signal integrity but the best for simplicity and fast high gain. This is the reason why t, The above graph shows a high pass filter with a cut-off frequency of 14Hz (18.6 -15. To bias the transistor you will require a Digital Multimeter that has the ability to measure voltage. The Technology of the Fuzz Face by R.G Keen.Fuzz Face Description by ScreaminFX. The quintessential fuzz. Although the core of the BOG is a modified Fuzz Face circuit, here we don’t like to stop where everyone does. Upon reducing the value of the 100K feedback resistor (from the emitter of Q2 to the base of Q1) I found that the operating point of the first transistor could be altered. var path = 'hr' + 'ef' + '='; The last block (the Feedback Network) will affect the rest of the analysis because it will influence the most important parameters: voltage gain, input impedance, output impedance and frequency response. Fuzz Face DIY kit "Good fuzz kit, ALPHA Pots, good quality jacks. Arbitrer Electronics manufactured the pedal from 1966 to 1975, Dallas Music Industries did a final batch in 1975-77, after that the production stopped. This is due to the C3 output high pass filter effect ( C3 - RVOL). During its lifetime the pedal went through some minor cosmetic but major sonic changes. Completed builds: Dallas Arbiter Fuzz Face,Tone Bender Professional Mk 3,Tone Bender 3-Knob,Baja BK Butler Tube Driver,Baja Real Tube Overdrive,Roger Mayer Octavia,EH Soul Preacher,Tech 21 XXL Distortion,MFOS Weird Sound Generator. Messages: 697. We want to take a moment here to explain how you can do this on your own for both the kit version and completed versions. The Erupter contains only one Bias control, with the fuzz level internally dimed and the Volume pre-set to a universal unity level. The key to building a good fuzz face is ensuring that transistors are getting the correct voltage. It creates a high pass filter together with RVOL that will determine the lowest frequency that gets out of the pedal. However, it can be considered as a bad output impedance, it is too high and can carry problems when it is placed in the pedal chain. With this emitter resistance added, the Common Emitter PNP major parameters (ignoring by the moment the feedback network) can be determined by the ratio between the collector resistors (R2 + R3) to and the emitter resistor (the portion of RFUZZ not shorted to ground through the 20uF cap). The germanium transistor needs to see the inductance/impedance from the guitar pickups. Discussion Paper About Fuzz FAce Batteries by DingoTone.com Arbitrer Fuzz Face by Fuzzcentral. 1.1 The transistors.2. In terms of design, the bypass capacitor C2 should have a reactance, at the lowest frequency you are interested to amplify, less than the value of RFUZZ. 3.1 Input Impedance. This is due to the RC filter created by C1 and the input impedance (5KΩ approx. Schematic diagram of a Fuzz Face adapted with a trimpot. The value of the output impedance can be calculated using the formula: Zout = RVOL//470ΩZout MAX = RVOL//470Ω=500K//470Ω = 469Ω. Synthrotek-MDIV-Eurorack-Clock-Divider-Multiplier, window.dojoRequire(["mojo/signup-forms/Loader"], function(L) { L.start({"baseUrl":"mc.us4.list-manage.com","uuid":"38f29b26bad12e4a62cf41410","lid":"99f032f6ee","uniqueMethods":true}) }). B = Feedback constant (not to be confused with the transistors, When the fuzz control increases the attack, the 20uF C, The FF frequency response is shaped by the three capacitors C, All harmonics below 31Hz will have 6dB/oct of attenuation, The plot below represents the total frequency response of the fuzz face, the different lines show the effect of the volume potentiometer. As a rule of thumb, Zin should be at least 1 MΩ. Solar Face Fuzz Fuzz Who doesn't love a Fuzz Face? So what we have here is basically standard Fuzz Face spec, originally Q2 resistor is paired with trimmer to set quite cold bias at 3v range. However, there are some other options, for a more compressed sound you can use β=90-120 for Q. Is equal to the input impedance of a common emitter stage. For small signals (less than 50mVpp), the input stage will first hit soft saturation on the negative semi-cycle of signal like in the image below, this asymmetric clipping distortion is very musical. ).However, there are some other options, for a more compressed sound you can use β=90-120 for Q1 and β=150-190 Q2.There are some circuits that help to measure the transistor gain. note: For the bias values showed above, the fuzz potentiometer is set to the midpoint (500Ω) The DC voltages might change due to transistor β variations, in this case, we are using a Q 1 with β=85 and Q 2 with β=120. Messages 2,186. They are common technologies still easy to find nowadays. These are the most important DC bias points of the circuit. Who wouldn't like to tweak their Fuzz Face bias on the fly? Trademarks, brand names and logos are the property of their respective owners. var addy_textc9796beda9bd2381890082165b7e7805 = 'info' + '@' + 'electrosmash' + '.' + 'com';document.getElementById('cloakc9796beda9bd2381890082165b7e7805').innerHTML += ''+addy_textc9796beda9bd2381890082165b7e7805+'<\/a>'; Some Rights Reserved, you are free to copy, share, remix and use all material. This analysis covers the first Arbitrer Fuzz Face model equipped with PNP germanium transistors from the first releases which are considered the best sounding. The Fuzz Face Mini pedal line features legendary Fuzz Face tones in smaller, more pedalboard-friendly housings with several modern appointments: true bypass switching, a bright status LED, an AC power jack and a convenient battery door. Great Germanium Fuzz Face-alike with 3rd Bias dial - not in wide circulation at all, best to buy from site - mjmguitarfx.com. Tabor. The second transistor serves a couple of purposes. e-mail us at This email address is being protected from spambots. Since both kits and completed pedals both come with bias tested transistors, you should not need to completely remove the electronics from the housing. 2.2 Components Part List / Bill of Materials. Unless you know what you're doing and have a positive ground PSU, you should use all these components, otherwise omit them and solder a jumper between J1 and J2. For the Fuzz Face circuit to be optimally biased, the collector of Q2 needs to be at 4.5 volts. The effect became very popular because Jimi Hendrix played it and there were not many distortion pedals around at that time.