Imifumei Handwired UltraFace Fuzz Pedal BC183 Transistor Based on EJ Fuzzface Tone, Price include the import duty to US buyer

UltraFace AU Component Configuration

• Vishay Dale 1/2W Carbon Film Resistors (matching original EJF1 factory spec)
• KEMET USA C0G Capacitors (replaces stock generic surface-mount capacitors)
• Philips BC Capacitors (metallic blue housing)
• IC USA Capacitors (light blue housing)
• Q1 Transistor: Genuine factory-matched BC183, identical to original EJF1 spec
• Q2 Transistor: Genuine factory-matched BC183C, identical to original EJF1 spec

Potentiometer Curve Optimization

To make this fuzz pedal genuinely playable and ergonomic, we retained all core original circuit parameters while applying modern acoustic optimization to all knob potentiometer curves:

• VOLUME Control: Upgraded to Type A (Audio/Logarithmic) curve. Delivers silky-smooth, gradual volume transition, eliminating the need for precise micro-adjustment of the knob.
• FUZZ Control: Custom-machined Type C (Reverse Logarithmic) curve — a signature circuit upgrade found in high-end premium fuzz pedals. It extends the entire effective gain range, originally confined to the final 10% of knob travel, across the full latter half of rotation. You now have an expansive adjustment range from 12 o’clock to 5 o’clock to finely sculpt distortion grain and harmonic texture, with audible timbre change at every minute of knob movement.

Precision Bias Calibration

No generic pre-set factory values. For the UltraFace Au pedal:We not only select premium-gain graded Fairchild BC183 series transistors, but also reverse-engineer and lock the core bias voltage value via direct measurement of the original EJ signature pedal.Every single UltraFace Au unit undergoes manual, individual bias voltage tuning, perfectly matching the authentic operating bias point of the original EJ signature pedal.

Premium Matched Silicon Transistors

The UltraFace Au is built with hand-sorted genuine Fairchild original BC183 and BC183C silicon transistors.

We exclusively use the exact same transistor spec as the original EJ signature pedal.

Every transistor pair is strictly gain-matched from the factory, paired with manual bias voltage fine-tuning to perfectly replicate the iconic original Cleanup dynamic response of the circuit.

Power Supply Modes Explanation

1. Internal Battery Power Supply
2. Current fully bypasses all filter circuitry and reverse-polarity protection diodes. This mode retains the natural dynamic response and compression characteristics inherent to battery internal resistance, delivering the most authentic, unaltered original timbre of a classic fuzz effect.
3. Isolated Independent Power Supply
4. Current passes through the complete power filtering circuit and reverse-polarity protection system. This delivers an ultra-quiet noise floor. Additionally, the minor voltage drop inherent to the circuit emulates the warm, organic tone and lingering sustain characteristic of dying, low-voltage old batteries.
5. Daisy-Chain Power Supply
6. Due to common-ground circuit properties, this mode bypasses the internal filtering and reverse-polarity protection circuits. The circuit receives maximum operating voltage and dynamic headroom, however its noise immunity is entirely dependent on the purity of your power supply.
7. WARNING: Unless you fully understand all operational risks and can guarantee absolute correct power polarity (negative center, positive barrel), only use internal battery power or isolated independent power supply. Improper daisy-chain connection will disable circuit protection and cause permanent component damage.

FAQ: Volume Knob Feel

Q: Why is the volume lower at the 12 o'clock middle position compared to the original pedal?A: This is a usability-focused upgrade.

The original potentiometer has an extremely steep curve: volume spikes drastically with even the slightest turn, leaving nearly all of the knob’s latter travel completely ineffective. We have upgraded it to a Type A potentiometer with far superior linearity, so the volume increases smoothly and uniformly as you rotate the knob.

Rest assured that the maximum output volume at full clockwise turn is identical to the original pedal. We have only redistributed the volume curve: the entire volume range that was originally crammed into the first 10% of knob travel is now evenly spread across the full rotation range.