UralTone FF Ge assembly instructions

The UralTone FF Ge is perhaps an adapted version of the more well-known Fuzz pedal kit: Classic, Arbiter Fuzz Face Distortion Unit. It was introduced by Arbiter Electronics Ltd in 1966 and soon the pedal was also discovered quite soon for the use of J. Hendrix in London and the rest is history.

The first version of the Fuzz Face circuit was implemented with Newmarket Ltd’s NKT275 Germanium transistors. Due to the usage in original Fuzz Face circuit, the genuine NKT275 is starting to be impossible to find at any reasonable price. The Uraltone FF Ge diy kit uses the MN21A transistor, which is close to NKT model in terms of measurement and sound characteristics. MN21 is also more stable to temperature fluctuations compared to its model, which facilitates use in different conditions.

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UralTone FF Ge - BOM

General guidelines to building kits

General guide for pedal builders in PDF format 

Check all the parts

Always check first that all parts are included in the delivery. If you find any problems please contact us by email or through the “contact us” form on the pages. Note that the components may look slightly different than in the photos. Also, note that the voltage specs of the parts may be higher than what is listed. Read all the notes at BOM (bill of material) carefully.

Building the pedal

Follow the order in which the images below are assembled. We try to keep component manufacturers and types the same, but sometimes we have to change the manufacturer or model of a part due to poor availability. So if a part is a slightly different color or higher voltage rating, all is good, each component has the required values marked on the side of the part.

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Start building from the footswitch. The front resistor of the LED is soldered first. This resistor is packaged separately in a bag of other parts of the hardware set.

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Press the foot switch onto the FS board. Note the installation direction, the hole in the threaded part will come up. The soldering heads on the plate may be narrow, so press the switch with sufficient force. The circuit board and switch will not get hurt!

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Cut five-cent lengths from the cord provided with the kit. Peel the insulation about 3mm apart, twist the strands together, and pre-solder the stripped wire ends.

NOTE: The LED will not be installed at this time!

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UralTone MKII pcb. The locations of all parts with their part numbers (designator) are printed on the board. C=capacitor, R=resistor, Q= transistor, D=diode etc. The values or types of parts corresponding to the designator can be found in the parts list provided with the kit.

Note: On PCB v1.01 D1 has print opposite way as it supposed to be. Refer right mounting direction on following step.

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It is a good idea to start with low / smaller parts, so that the parts are pressed against the surface of the pcb when they are soldered to the board and the board is turned over on a table or similar surface. Start by populating the resistors on a pcb. Resistors are marked R1, R2, etc. Resistor values are marked with colored rings. To interpret these, see the table provided with the kit. The correct values can also be measured or compared to the color rings in the image above. It doesn’t matter the direction in which the resistors are installed, but for readability, it’s a good idea to install them in the same direction, depending on the printing on the board.

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Solder diode D1. Note the right mounting direction / polarity of component.

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Install the capacitors on the pcb. Note the mounting direction of the electrolytic capacitors (C1, C2, and C5), the printed stripe on the side of the part marking the negative terminal of the capacitor corresponds to the white semicircular pattern printed on the circuit board. Axial capacitors has goove on the other end of the part. This is aligned according the silkscreen on the pcb. C3 has no polarity. C4 is not used on circuit.

Note: after this the D1 is wrong way on pictures and resistors R3 and R4 are switched. Do not fit parts like this.

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Solder the trimmer RV1.

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Solder the trasistors Q1 and Q2. These are selected for the circuit per amplification. Use smaller value on Q1. On the picture Q1 has value 55 and Q2 67.

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Same as above. Note the small space under the transistor package. This keeps the heat of soldering to enter the transistor. Do not leave too long wires, the package has voltage / signal on metal body. Do not short this any metal parts.

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Solder the potentiometers to the pcb. It is advisable to solder the potentiometer middle foot first and then check that it is on the surface of the plate and straight. When the position is correct, solder the outermost pins.

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Solder the footswitch board made at the beginning and the battery clip to the main pcb. The wires of the battery clip are threaded through the pcb and soldered to the pads. This results in strain relief on the conductor. The wires of the clip can be shortened slightly, approx. 5cm. The appropriate length of cord can be measured by temporarily placing the parts inside the case.

Jacket installation in case

Install the Jacks in the case. Not not overtight, since you need to rotate them when the wires are soldered.

DC jacket installation

Insert the DC jack into the mounting hole.

Ledin pujottaminen asennuspaikkaansa

Slide the LED into place. Note the polarity of the LED. On this circuit the LED is isntalled backwards on the PCB due positive ground. The shorter leg / chamfered LED is marked on the pcb. When viewed vertically (wires up), the beveled side / shorter coupling foot comes to the right. Washers are placed in the threaded portion of the footswitch to await installation.

Efektin elektroniikka

Slide this circuitry into the enclosure.

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Install the board in the case. When installing the effect pcb, care must be taken that the DC jack does not fall out of place. (This can be prevented with a non-powered DC cable or plug). Install the front panel. Tighten the nuts with your fingers and fit the plate neatly into place. When everything sits as desired, soldr the DC jacket closed. The LED is installed by pushing it through the front panel and soldering it.

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Solder the jacks. The solder lugs of the interior jacket are pressed in before soldering. The jacks can always be rotated for soldering. After soldering, the jacket is twisted for the next wire. Start soldering as seen from the lower lug, so the wired wires move deeper into the housing and are not in front when the next wires are soldered in place.

The UralTone effect kits are delivered with two different types of input jacks. Please refer how to solder instructions found here: https://en.uraltone.com/blog/input-jack/

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Attach the potentiometer knobs and install a 9V battery. Now you are ready to take your guitar / bass / synth and test how does it sounds. If all works, we still have to bias transistors to work as designed.

Insert the black measuring probe into the screw hole on the bottom of the effect housing (this is ground). Measure the voltage at TP1. Adjust the readout to 6-8Vdc by turning RV1.

The values given are recommendations. Always listen and make sure pedal sounds as good as possible. If you pedal sounds best with some other voltages, that's fine, sound quality is the most important thing!