fuzz face bias

The output capacitor C3 blocks the DC level from saturating any device following the Fuzz Face. The fuzz face was re-issued from 1986 to 2000. Amplifiers use current or voltage as input or outputs, you can check the amplifier classification. 4.1 Output Impedance. In 1993 Dunlop took over the production selling the fuzz face in different flavors. They are common technologies still easy to find nowadays. Resources. If we are looking for high gain it is a common practice to have part or all of the emitter resistor grounded with a bypass capacitor. (Pedal must be powered on). Reduce nonlinear distortion: make the gain constant. Messages: 697. Discussion Paper About Fuzz FAce Batteries by DingoTone.com Arbitrer Fuzz Face by Fuzzcentral. The plot below represents the total frequency response of the fuzz face, the different lines show the effect of the volume potentiometer. It is important to select the right transistor from the whole batch in order to archive the best effect performance. Completed pedals are biased before and after installation into the PCB to help make sure that you have a great sounding pedal upon initial use. You need JavaScript enabled to view it. The second transistor serves a couple of purposes. Note that the output signal is not completely flat when it clips (it is slightly tilted), this feature adds more character to the sound . I’ve tried a Rat, Boss DS2, Fuzz Face, Red Witch Fuzz God, Big Muff, and enjoyed them all but couldn’t get along with any of them long term. AC128 Transistor datasheet 1 pdfAC128 Transistor datasheet 2 pdf. PSUs with electronically isolated outputs may work, but it’s not ideal, and many vintage and vintage-style Fuzz Face owners resign themselves to using batteries. The fuzz was a little weak with classic combo AC 128 and also with 2N404 even combo, maybe my choice should have been for hotter trans! DEXTER74 Strat-O-Master. As the volume goes lower (blue line), the graph shows a steeper slope with more high content. 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. As a rule of thumb, Zin should be at least 1 MΩ. var addy0bbee1a085a5092a78cb1fa82c758b68 = 'info' + '@'; The relationship between feedback and gain is explained in the Feedback Network Section. The internal series resistance of the battery is added to the 470Ω R3 resistor, modifying the value by a significant amount. For component economy, the power supply does not include any capacitors to remove ripple from the power line which is something common in raw fuzz pedals. I think the Arbiter-England one didn’t use the NKT275 germanium transistor; in those days we used the AC128. Making this cap bigger will let more low frequencies out. Since both kits and completed pedals both come with bias tested transistors, you should not need to completely remove the electronics from the housing. It's the "middle" voltage, the spot where a waveform is centered on. addyc9796beda9bd2381890082165b7e7805 = addyc9796beda9bd2381890082165b7e7805 + 'electrosmash' + '.' + 'com'; Mar 16, 2018 - The Fuzz Face is a distortion guitar pedal designed in London by Arbitrer Electronics Ltd in the autumn of 1966. Drives & Fuzz Kloned Centaur. The main difference is that the Fuzz Face is biased slightly colder, making it more usable in warm environments. Quick View. This analysis covers the first Arbitrer Fuzz Face model equipped with PNP germanium transistors from the first releases. Fuzz Face DIY kit "Good fuzz kit, ALPHA Pots, good quality jacks. You need JavaScript enabled to view it. 1. 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. 3.1 Input Impedance. So the feedback network has a negative impact on this parameter. 4.3 Power Supply.5. Arbitrer Electronics manufactured the pedal from 1966 to 1975, Dallas Music Industries did a final batch in 1975-77, after that the production stopped. It was based on the Tone Bender circuit but had its own sound completely. The voltage gain (AV) can go from 8.2 to as high as the transistor's basic internal gain (when RFUZZ is maxed out). Q1 BIAS 22K Trimmer Q2 BIAS 10K Trimmer Q1 MP39B Q2 GT308V FUZZ 1KB (2KB) VOL 500KA BOM Adjust bias trimmers until it sounds sweet. Speaking of feedback, from my noodling with a Fuzz Face circuit in Multisim (electronic workbench/Pspice type of program) I found that lowering collector resistor resulted in extra current travelling through that path. addy0bbee1a085a5092a78cb1fa82c758b68 = addy0bbee1a085a5092a78cb1fa82c758b68 + 'electrosmash' + '.' + 'com'; You need JavaScript enabled to view it. So, like all Deep Trip pedals, the BOG takes the usual 9V, center negative power supply, as most standard pedals do. This last quote from D. Cornell explains why the production switched to the modern, temperature independent, cheaper and stable silicon transistors like the BC183L, BC183KA, BC130C, BC108C, BC109C, BC209C, and BC239C. The 20uF is so big that almost all the frequencies get full amplification. This gain variation is crucial in the design, the best match uses a low gain in the first stage (β=70-80 approx.) These instructions should also help with other Fuzz Face clones as well. 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. Desensitize the gain: make the gain value less sensitive to transistors (i.e component variation caused by temperature). This maybe a tough one, but how and where do you measure the bias on the EJ fuzz? 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. 2.2 Components Part List / Bill of Materials. 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. Is equal to the input impedance of a common emitter stage. 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. 8.1 Datasheets. Location: Darwin,Northern Territory Australia Has thanked: 75 times Been thanked: 235 times. Who wouldn't like to tweak their Fuzz Face bias on the fly? During its lifetime the pedal went through some minor cosmetic but major sonic changes. The general amount of gain is considerably reduced due to the feedback network. Fuzz Face Output Stage. Solar Face Fuzz Fuzz Who doesn't love a Fuzz Face? The germanium transistor needs to see the inductance/impedance from the guitar pickups. The Fuzz Face. How does the feedback work in the Fuzz Face? If you fancy building your own fuzz face, our good friend Doctor Tweek also sells a nice range of silicon transistors (including BC108’s and 9’s). This effect is more noticeable when the gain of the pedal is low because it has more signal feedback coming from the output through R4. The value of the output impedance can be calculated using the formula: Zout = RVOL//470ΩZout MAX = RVOL//470Ω=500K//470Ω = 469Ω. Supposedly Hendrix would go through a box of new Fuzz Faces to pick the one he liked best. For the Fuzz Face circuit to be optimally biased, the collector of Q2 needs to be at 4.5 volts. BUT the output of the pedal is not directly taken from Q2 collector, there is a voltage divider created by R2 and R3 (the power supply is effectively at AC ground). Image result for fuzz face bias pot. 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. Fuzz. Schematic diagram of a Fuzz Face adapted with a trimpot. Using a smaller resistor, the filter will cut more lows out (fc=160Hz) which will result in a brighter sound. The Fuzz Face low input impedance will load the guitar pickups. This is due to the RC filter created by C1 and the input impedance (5KΩ approx. It can be broken down into three parts: Input Stage, Output Stage and Feedback Network. As the volume goes lower (blue line), the graph shows a steeper slope with more high content. Other fuzz pedals like the Big Muff Pi have a more distinctive frequency response that could shape the tone in a more innovative way. Silver Supporting Member. In terms of design, the bypass capacitor C, All the frequencies over 8Hz get full amplification. It exhibits an attenuation in the low frequencies (high pass filter) with a fc=14Hz inherited from the input stage. Jack in, Jack out, battery clip, DPDT foot-switch. 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. Great Germanium Fuzz Face-alike with 3rd Bias dial - not in wide circulation at all, best to buy from site - mjmguitarfx.com. My sincere appreciation for D.Clark support.Thanks for reading, all feedback is appreciated  This email address is being protected from spambots. The single layer PCB with through-hole components fits without problems inside the oversized cast iron enclosure. The fuzz face has a negative feedback called shunt-series feedback (Current Controlled Current Source CCCS). 4.2 Voltage Total Gain. Feed the output from one block back into itself? The quintessential fuzz. This gain variation is crucial in the design, the best match uses a low gain in the first stage (β=70-80 approx.) The trimmer resistor can be dialed in by ear to suit the desired tone if you so desire. 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. The big amount of gain will clip the signal easily creating large amounts of higher harmonic content. 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. This information is for those seeking precision. Saved by Danyo. Dennis Cornell: "All the transistors worked in a very similar way and all did the job, but they did give a slightly different tone. 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}) }). Ivor Arbiter took the round shaped enclosure idea from a microphone stand and it was the first pedal including a DPDT stomp-switch. The value usually does not get as low as -5.5dB, the series resistor of the battery should be taken into consideration and will raise the output level. 6 = 3dB) all frequencies below 14Hz will suffer an attenuation 6dB/oct. The fuzz is not designed to overdrive the following. It's useful to adjust with germanium transistors because the bias can change with temperature. Synthrotek is now testing and bias testing all of the Germanium transistors that we send with kits and completed units. The fuzz face was re-issued from 1986 to 2000. Reduce the noise: minimizing the contribution to the output of unwanted electrical signals. and a high gain in the second stage (β=110-130 approx.). e-mail us at This email address is being protected from spambots. [clarification needed] The original instructions even described the Fuzz Face as a "Tone-Bending" unit. var prefix = 'ma' + 'il' + 'to'; 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. USE THE INVERTER OR WIRE FOR POSI-GND. 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. FF Sound Signature II: Soft Clipping - Hard Clipping: As the second stage is driven harder, it can reach hard clipping in both semi-cycles of the signal. PNP Fuzz Face circuits are not compatible with power supplies running a line of modern pedals because the positive is grounded rather than the now-conventional negative. In amplifier design the degenerative (negative) feedback is used to: The properties above are obtained at the expense of a reduction of gain. ).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. 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. This voltage divider created by R2 and R3 will greatly reduce the output level. 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. Because the fuzz is so dependent on individual transistors there can be huge variation in the way these sound. That said, any of our matched pairs can usually be made to work in any of the clones. 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). It creates a high pass filter together with RVOL that will determine the lowest frequency that gets out of the pedal. This is the reason why t, The above graph shows a high pass filter with a cut-off frequency of 14Hz (18.6 -15. I’m not looking to copy a specific sound, just to use something for original music not to copy other people’s tone. For the bias values showed above, the fuzz potentiometer is set to the midpoint (500Ω), The DC voltages might change due to transistor, The important settings to get the best sound out of a Fuzz Face is to have Q1, For this math calculation the feedback network is ignored but in practice, it will lower the input impedance to 5K, load the guitar pickups. 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. My sincere appreciation for D.Clark support. 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. This email address is being protected from spambots. I needed to use a 50k bias pot in order to get down to 4.5 V on the Q2 collector, but this may be because I used 100k gain pots and a 10k fuzz pot - which is worth trying. 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. Arbitrer Electronics manufactured the pedal from 1966 to 1975, Dallas Music Industries did a final batch in 1975-77, after that the production stopped. If we take into consideration the feedback network, once again the second stage will not reach values as 18dB. var addy_text0bbee1a085a5092a78cb1fa82c758b68 = 'info' + '@' + 'electrosmash' + '.' + 'com';document.getElementById('cloak0bbee1a085a5092a78cb1fa82c758b68').innerHTML += ''+addy_text0bbee1a085a5092a78cb1fa82c758b68+'<\/a>'; \[\\r_{\pi } = \frac{(\beta +1)\cdot Vt}{I_{EQ}}=\frac{(\beta +1)}{gm}= \frac{(70+1)}{0.0088}= 8K\], \[A_{V}=-g_{m}\cdot R_{C}= -g_{m}\cdot R_{1}= 0.0088 \cdot 33K = 290\: (49dB)\], \[g_{m}=\frac{I_{e}}{V_{T}}= \frac{0.22mA}{25mV}= 0.0088\], \[A_{V}=\frac{R_{C}}{R_{E}}= \frac{R_{2}+R_{3}}{R_{pot1}}\], \[A_{V}min=\frac{470+8K2}{1K}= 8.2\: (18dB)\], \[f_{c}=\frac{1}{2\pi R C}=\frac{1}{2\pi \cdot R_{pot1}\cdot  C_{2}}=\frac{1}{2\pi \cdot 1K \cdot 20uF}= 7.9Hz\], The Fuzz Face is a distortion guitar pedal designed in London by Arbitrer Electronics Ltd in the autumn of 1966. var path = 'hr' + 'ef' + '='; 6 = 3dB) all frequencies below 14Hz will suffer an attenuation 6dB/oct. Thanks for reading, all feedback is appreciated. The Fuzz Face Models. In the above image, the output voltage at Q2 is shown under the action of the RFUZZ potentiometer (the volume is set to max). The Fuzz Face has a very low input impedance that will change with the position of the RFUZZ potentiometer (between 5.2KΩ and 8.4KΩ in the simulation). The Technology of the Fuzz Face by R.G Keen.Fuzz Face Description by ScreaminFX. Thread starter Dannyz; Start date Feb 24, 2020; Tags dunlop fuzz face; Dannyz Member. In this case, the total voltage gain measured at Q2 collector is around 19.5dB. When the gain goes high the feedback is smaller and the high pass filter influence is less important. 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. Sure thing! During its lifetime the pedal went through some minor cosmetic but major sonic changes. The fuzz is not designed to overdrive the following system by level. In this video I will set the trimpots of my Dunlop Fuzz Face JDF2Hope you find it useful The above graph shows a high pass filter with a cut-off frequency of 14Hz (18.6 -15. Also we included in this project a bias control, cause we all know how fun is to experiment with starving fuzzes!
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