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The 7 min fuzz is a low part count high-gain circuit that produces a very respectable, thick sounding fuzz tone. However
this is just one of the sounds capable from this circuit. It is quite adaptable and if you have purchased the experimenters
kit you can follow along with my basic notes on how to tweak it! The BOM below lists the 'standard' configuration (thick
sounding fuzz).
R1
C1
C2
7 Min Fuzz
Bill of Materials
Resistors
10k
Capacitors
1uf (105)
100nf (104)
Diode
D1
BAT41
Transistor
Q1
MPSA13
Potentiometer
Volume
100ka Log
www.diyguitarpedals.com.au
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Related Manuals for DIY Guitar Pedals 7 Min Fuzz
Summary of Contents for DIY Guitar Pedals 7 Min Fuzz
- Page 1 7 Min Fuzz The 7 min fuzz is a low part count high-gain circuit that produces a very respectable, thick sounding fuzz tone. However this is just one of the sounds capable from this circuit. It is quite adaptable and if you have purchased the experimenters kit you can follow along with my basic notes on how to tweak it! The BOM below lists the ‘standard’...
- Page 2 www.diyguitarpedals.com.au...
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Page 3: Reference Designators
Orientation and Polarity of the Components Polarity of the BAT41 Diode Note the polarity of the BAT41 diode. The Band on the diode must match up with the band printed on the circuit board: Orientation of the MPSA13 Transistor The Transistor must also be installed into the circuit the correct way around. Note the image of the transistor printed onto the circuit board. - Page 4 7 Min Fuzz – Bass Guitar Mod The Capacitors included in the 7 Min Fuzz Kits are selected for electric guitar, however the circuit will work with bass guitar as well with only a small modification; higher value capacitors on the input and output, C1 and C2 (available on the webstore).
- Page 5 7 Min Fuzz – Gain Control Mod Adding resistance to the emitter of the 7 min fuzz transistor will reduce the gain of the circuit. We can add a modification for adjusting the gain of the effect by adding a potentiometer to the circuit, a device that increases resistance as you turn the dial.
- Page 6 Tip for soldering 9mm Alpha Pots www.diyguitarpedals.com.au...
- Page 7 Note, you can still test your effect with 2 mono jacks, just combine the negative of the battery with the ground input sleeve connection. A DC Jack will also work for a power source, replace the battery above with a dc jack. www.diyguitarpedals.com.au...
- Page 8 Off Board Wiring Diagram Using a non-switched Miniature DC Jacks and 2 Mono Jacks (kit option with diyguitarpedal kits) “CLR” = Current Limit Resistor. This resistor (included with your LED and bezel controls the brightness of the led and stops the LED from blowing.
- Page 9 www.diyguitarpedals.com.au...
- Page 11 7 Minute Fuzz Circuit Analysis for understanding technical purposes. 1. 7 Minute Fuzz Circuit. The 7 Minute Fuzz schematic can be broken down into some simpler blocks: Power Supply, Transistor Input and Clipping, and Volume Control. The circuit is designed around a single op-amp gain and hard clipping while using transistors to handle buffering and boosting the input signal and buffering a recovery stage at the end.
- Page 12 2. Transistor Input and Clipping Stage. The single input stage transistor provides the amplification of the signal while also providing some clipping and input/output impedance to the circuit. The Q1 transistor just needs to be high-gain (h of 5,000 minimum per the MPSA13 datasheet). The lower the h value on the selected Q1 transistor, the less saturation and fuzz will occur and the higher the h value, more saturation and...
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Page 13: Voltage Drop
Though positioned schematically as a soft-clipping diode, D1 is not soft clipping in the same way as the diodes in a Big Muff Pi or other soft-clipping transistor fuzz pedals. What it does is bias the base of Q1 to one voltage drop below the collector voltage. - Page 14 3.1 Input Impedance and High Pass Filter. As covered in the Bass Control Mod section, C1 forms a first order high pass filter together with the input impedance of Q1. The input impedance is also different for negative and positive swings because it is partially controlled by D1. For the negative swing, the input impedance is very low and changes with the amplitude of the signal.
- Page 15 4. Volume Control. The output is controlled by a volume potentiometer that goes to ground, along with an output capacitor to keep any DC current from hopping out of this pedal and into the next (or amp). The 100nF C2 output capacitor blocks DC and provides simple high pass filtering. C2 and Volume Pot create a high pass filter.
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