DIY Guitar Pedals Oil Tanker Fuzz Скачать руководство пользователя страница 23 | Manualshive

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DIY Guitar Pedals Oil Tanker Fuzz Скачать руководство пользователя страница 23

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www.diyguitarpedals.com.au

How does the feedback work in the Oil Tanker Fuzz?

The job of the feedback network is basically to reduce the huge gain of the Oil Tanker Fuzz stages, making the whole
circuit more stable and independent from problematic transistors:

•

When the fuzz control (1KΩ pot) is set to minimum, a big amount of signal is sent back to the input, creating a
big feedback loop and reducing the total pedal gain (left image below).

•

When the fuzz control increases the attack, the 22uF C2 cap will gradually shunt the negative feedback to the
ground, thus letting the circuit operate with more gain (right image below).

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Содержание Oil Tanker Fuzz

Страница 1: ...e bill If you want nice beefy explosive fuzz that makes your bass sound like an oil tanker scraping up on concrete give this pedal a shot This pedal is based around several fuzz pedal ideas and focuses on bass delivery for stage and recording mix scenarios This also works great as a refined fuzz for guitar players alike The pedal uses 3 pot controls Volume Tone and Fuzz Beginner friendly be sure t...

Страница 2: ...acitor Resistor C1 22nF film R1 1M C2 22μF Electrolytic R2 100K C3 100nF film R3 100K C4 33nF film R4 1K C5 220nF film R5 5 6K Diode Potentiometer D1 1N4001 Fuzz 1kb 16mm Volume 500ka 16mm Transistor MOSFET Tone 10kb 16mm Q1 2N5088 Q2 BS170 Q3 IRF520 TO 220 Q4 IRF520 TO 220 ...

Страница 3: ...uitarpedals com au REV REV A PCB Spacing The Oil Tanker Fuzz PCB is spaced for 1590B sized enclosures or larger Pot Spacing The Oil Tanker Fuzz PCB mounted potentiometers are spaced for Alpha 16mm potentiometers ...

Страница 4: ...acitors wiring and then potentiometers 1 1 Resistors Resistors are small passive components designed to create a resistance of passage of an electric current For this pedal we will be using 1 4 Watt resistors These can either be 5 tolerance carbon resistors or 1 tolerance metal film resistors Orientation of which way is up doesn t matter so you can install them either way After installation and so...

Страница 5: ...one called out in the bill of materials will require that you check the datasheet of the transistor and check which legs are what pins for it to function properly After installation and soldering do not forget to clip the remaining legs from the PCB 1 3 Capacitors film Film capacitors are small passive components designed to hold a small amount of charge in a circuit Orientation of which way is up...

Страница 6: ...e isn t room to have it stand straight up After installation and soldering do not forget to clip the remaining legs from the PCB 1 5 Capacitors electrolytic Electrolytic capacitors are small passive components designed to hold a small amount of charge in a circuit Electrolytic capacitors are typically polarized so orientation will matter After installation and soldering do not forget to clip the r...

Страница 7: ...ore potentiometers are soldered in place can be advantageous Colored wire doesn t change the properties but using color codes for hot and ground wires like red being hot and black being ground are common place Typically stranded hook up wire AWG 24 or 22 is used for this task Using wire strippers strip away about 1 8 3mm of the wire from either end and then using a soldering iron tin the exposed t...

Страница 8: ...s pedal can utilize 16mm pots These are typically installed on the backside of the PCB and uses the included washer and jam nut to mechanically secure the PCB to the enclosure via a strategically drilled hole on the enclosure Orientation of potentiometer is preferred to line up the knob on the silk screen with the knob of the potentiometer ...

Страница 9: ...9 www diyguitarpedals com au 1 8 Off Board Wiring Diagram Potentiometers are variable resistors that are used for controlling aspects of the pedal Using a non switched miniature DC Jack and 2 Mono Jacks ...

Страница 10: ...10 www diyguitarpedals com au ...

Страница 11: ...e Feedback Network Tone Control and Output Stage The circuit is designed around a BJT MOSFET pair for gain After that a small low pass filter tone control and some hard clipping with soft knees via more MOSFETs The input impedance on the Oil Tanker Fuzz is close to 3 4K Ω which is very low and will load guitar pickups A recommendation would be to put this pedal first on the pedal chain just after ...

Страница 12: ...und 1mA The diode D1 protects the pedal against adapter reverse polarity connections 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 The usual solution in guitar pedals is to add some power filtering by placing 47 100uF cap together with a 100nF from the 9v to ground ...

Страница 13: ... Input Impedance Is equal to the input impedance of a common emitter stage It can be calculated as Zin Qin 1 1 R1 1 β re Assuming the β gain of the Q1 transistor is 100 which are typical of the 2N5088 in this circuit and that the emitter leg signal resistance is 25mV 1mA or 25Ω VT is the thermal voltage of a transistor at room temperature the value is approximately 25mV The minimum impedance for t...

Страница 14: ...is at when no signal is going into the pedal Typically this is found to be at 2 54V when using 2N5088 transistors on this circuit They can range from 2 5V 2 7V depending on tolerances With this information we can now calculate the gain of the first stage First we need to calculate the IE which is the DC emitter current To calculate we use the following formula IE VCC VC R3 9V 2 54V 100 000 0 00006...

Страница 15: ...10K potentiometer is set As the 9V rail is just a rail to calculate and understand the tone filtering going on you can assume ground So to redraw this to make it easier to understand see the below figure RO is the calculation of R4 which is 1K in parallel to the maxed value of VR2 which is 500K This would be calculated at 1 RO 1 R4 1 RvolMAX 1 RO 1 1 000 1 500 000 1 RO 0 001 0 000002 1 RO 0 001002...

Страница 16: ...clockwise the tone pot becomes a 10K resistor between C4 and C5 This is when the tone becomes its most bright Since C5 is much larger than C4 in capacitance we can say C5 is a short to ground rail when calculating the filter Now we have a two pole low pass filter so we will need to recalculate the value of RO as it will be RO in parallel with the 10K Tone Pot This would look like RO OLD 10K 907Ω f...

Страница 17: ...rent The 5 6KΩ R5 resistor is the drain resistor for the Q2 MOSFET which help sets the voltage gain bias points and maximum drain current The 100nF C3 capacitor is coupler capacitor to send the AC signal out to the volume potentiometer without any DC The VR2 500K volume potentiometer is being used to control signal volume by sinking some of it to ground The Q2 MOSFET is the core of this amplifier ...

Страница 18: ...s just cutting out DC noise from leaving the pedal and going into the next which is a good thing However all the bass and sub frequency bass will leave the pedal if above 3 2Hz So using a 100K volume pot and 10nF C3 cap fc 1 2πRC fc 1 2π RvolMAX C3 fc 1 2π 100K 0 01uF fc 1 2π 100 000 0 00000001 fc 160 Hz Now frequencies get cut under 160Hz still protecting the next pedal from low frequency DC nois...

Страница 19: ...o R4 Zout 500K Parallel to 1 000 Ω 998Ω The output impedance is affected by the feedback network and has a real value of 1 88KΩ measured at 1 KHz with RVOL 500KΩ This value varies with the volume control level and the fuzz control position It is however well under 10KΩ of resistance in most situations so it still is on the upper end of ideal ...

Страница 20: ...PEDAL Attenuation of R4 R4 R5 19 5 16 4 3 1dB This voltage divider created by R4 and R5 will greatly reduce the output level The value usually does not get as low as 3 1dB the series resistor of the battery should be taken into consideration and will raise the output level 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 ...

Страница 21: ...ith harder playing The second amplifier stage can make the clipping harder with sharper squared corners under the fuzz potentiometer action After the clipping from the MOSFET has occurred the MOSFETs Q3 and Q4 give addition hard clipping but with a soft knee due to the diodes internal to the MOSFETs For example with the tone knob at noon the pre clipped wave form looks like this right before the C...

Страница 22: ...nt Reduce the noise minimizing the contribution to the output of unwanted electrical signals Control the input output impedance raising or lowering their values Extend the bandwidth of the amplifier The properties above are obtained at the expense of a reduction of gain As a rule of thumb with more feedback there is less global gain following the formula AFB AOL 1 BFBAOL Where AFB Total current ga...

Страница 23: ...stable and independent from problematic transistors When the fuzz control 1KΩ pot is set to minimum a big amount of signal is sent back to the input creating a big feedback loop and reducing the total pedal gain left image below When the fuzz control increases the attack the 22uF C2 cap will gradually shunt the negative feedback to the ground thus letting the circuit operate with more gain right i...

Страница 24: ...24 www diyguitarpedals com au 8 Voltage Readouts Below are the voltage readouts for the Oil Tanker Fuzz assuming 9V Power Supply KNOBS VOL MAX TONE MAX FUZZ MAX ...

Страница 25: ...e ceiling of upper frequencies allowed keeping more of the bass and less treble on the bright end of the tone knob Decreasing the capacitance of C4 to 1nF for example will allow more of the upper frequencies to pass on the bright end of the tone knob C5 defines the lower boundary of the tone knob and what frequencies and harmonics are cut out Increasing its capacitance value to 470nF for example w...

Страница 26: ...26 www diyguitarpedals com au 10 Schematic ...

Страница 27: ...5 15 2021 9 04 AM C Users evincent Documents eagle _Pedals Oil Tanker Fuzz Oil Tanker Fuzz 1590B Enclosure brd IN OUT STOMP LED POWER VOL TONE SUST ...

Страница 28: ...5 15 2021 9 04 AM C Users evincent Documents eagle _Pedals Oil Tanker Fuzz Oil Tanker Fuzz 125B Enclosure brd STOMP LED POWER IN OUT VOL TONE SUST ...

Страница 29: ...11 5 2018 6 59 AM C Users evincent VINCENT Documents eagle Pedals Oil Tanker Fuzz Oil Tanker Fuzz Layout brd VOL TONE SUST 33 0 52 1 7 2 15 2 7 6 26 0 44 5 ...

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