Electra Distortion Build Guide

How to build the silicon Electra distortion on stripboard.
ImportantPrototype design

This circuit has been simulated but not built yet. The layout is checked against the schematic by the script that draws it, and the voltages in this guide are simulated, not measured. Consider trying it on a breadboard first.

Assembly Procedure

  1. Prepare your workspace

    Find a clean, well-lit area to work. You will need the following:

    • Soldering iron and flux-core solder
    • Small wire cutters and wire strippers
    • Multimeter (you use it to check cuts, parts, and voltages)
    • A 3 mm (1/8 in) drill bit or a stripboard track cutter
    • Heat gun or lighter for heat-shrink tubing
    • Helping hands, or similar device, to hold parts while soldering

  2. Gather the parts

    The Electra is one transistor gain stage followed by a pair of clipping diodes. The original used germanium diodes. This version uses a three-way toggle to pick 1N4148 silicon diodes, no diodes, or two LEDs.

    CountPartValueNotes
    1Stripboard16 × 7 holes0.1 in pitch, strips along the 16-hole length
    1Transistor, Q12N3904Or 2N2222, BC337-25, C1815-GR, S8050-D
    1Resistor, R12.2 MΩ (red, red, green)
    1Resistor, R2470 Ω (yellow, violet, brown)
    1Resistor, R34.7 kΩ (yellow, violet, red)
    2Film capacitors, C1 and C2100 nF (104)
    2Diodes, D1 and D21N4148
    2LEDs, D3 and D4Same color, so both halves of the wave clip alike
    1Potentiometer, DRIVEB100k16 mm, linear
    1Potentiometer, VOLUMEA100k16 mm, audio (log)
    1Toggle switch, CLIPSPDT on-off-on
    13PDT footswitch9 solder lugs
    1LED and bezel5 mmEffect-on indicator
    1LED resistor4.7 kΩ (yellow, violet, red)
    21/4 in jacksStereo (input), mono (output)
    19 V battery snap
    —Hookup wire, heat-shrink tubing

  3. Try it on a breadboard (optional)

    Because this design hasn't been built yet, you can build it on a half-size breadboard first. The breadboard layout wires the jacks straight to the circuit, without the footswitch. Select the diagram to open the full-size image.

    Electra breadboard layout: Q1, R1 to R3, C1, C2, and both diode pairs on a half-size breadboard, with the pots, clipping switch, and jacks wired off the board

  4. Learn the board

    Stripboard has copper strips running along its length. Every hole in a strip is connected, so the strips do the wiring for you. You break a strip where two parts must not connect.

    Holes are named by row and column. Rows run A to G from top to bottom, and columns run 1 to 16 from left to right, with the parts on top and the copper underneath. For example, E16 is row E, column 16. Keep the layout diagram open while you work.

    Electra stripboard layout: component side with every part and its holes, and the copper side showing the two track cuts
    ImportantThe copper side is a mirror image

    When you flip the board over to cut or solder, left and right swap. Column 1 is now on your right. The layout's copper-side view is already flipped for you, so use that view whenever the copper is facing up.

    The schematic shows the same circuit. It's useful when you check voltages or trace a fault.

    Electra schematic: DRIVE pot into C1 and Q1's base, R1 from collector to base, C2 to the clipping diodes and LEDs selected by the CLIP switch, then the volume pot

  5. Cut the tracks

    Two holes need their copper cut: C3 and F8. Cut the tracks before you install any parts.

    1. Mark the cuts

      With the copper side up, find each cut on the copper-side view and mark it with a fine marker. Count columns from the right-hand edge, because the board is flipped.

    2. Cut each hole

      Place the drill bit in the marked hole and twist it by hand, with light pressure, until the copper ring around the hole is gone. You only need to cut through the copper, not through the board.

    3. Check every cut

      Set your multimeter to continuity. Check C2 to C4 and F7 to F9. Neither may beep. If one beeps, a sliver of copper remains: twist the bit again, or scrape the gap with a hobby knife.

  6. Install the resistors

    Resistors are not polarized. For each one, bend the leads to fit the holes, push it flat against the board, solder, and trim. Check each value with your multimeter before you solder it.

    ResistorValueHoles
    R34.7 kΩA2 to B5 (diagonal)
    R12.2 MΩB9 to C12 (diagonal)
    R2470 ΩD10 to G10 (crosses strips E and F)

  7. Install the clipping diodes

    D1 and D2 face opposite ways, so one clips the top of the wave and the other clips the bottom. D3 and D4 do the same. The band on a 1N4148 marks its cathode. On an LED, the short lead is the cathode.

    DiodeAnodeCathode
    D1 (1N4148)E2F4 (band)
    D2 (1N4148)F5E7 (band)
    D3 (LED)E12 (long lead)F12 (short lead)
    D4 (LED)F14 (long lead)E14 (short lead)
    CautionCheck each pair is opposed

    If both diodes in a pair face the same way, that switch position clips only one half of the wave and sounds lopsided. Check the bands and short leads against the table before you solder.

  8. Install the capacitors

    Film capacitors are not polarized.

    • C1 (100 nF): C2 to C5. It lies along strip C, over the cut at C3, so it connects the two pieces of the strip.
    • C2 (100 nF): B15 to E15.

  9. Install the transistor

    Install Q1 last, because it's the most heat-sensitive part. Work quickly: about 2 seconds per joint.

    Q1's flat face points right, toward column 16: C in B7, B in C7, E in D7.

    CautionCheck the pinout of your transistor

    When you look at the flat face with the leads pointing down, a 2N3904, 2N2222, or BC337 reads E, B, C from left to right. A C1815 or S8050 reads E, C, B. With an E-C-B part, bend or rotate it so each lead still lands in the hole given for that lead. Check your part's datasheet if you're unsure.

  10. Attach the off-board wires

    Solder a wire into each pad below from the component side, long enough to reach its part in the case. Leave some slack.

    PadGoes toSuggested color
    A14Battery snap +Red
    A16LED resistor, then the LED's long leadRed
    C1DRIVE lug 2Green
    E16VOLUME lug 3Blue
    F1CLIP switch lug 1Yellow
    F16CLIP switch lug 3Yellow
    G2Input jack sleeveBlack
    G4DRIVE lug 1Black
    G6CLIP switch lug 2 (middle)Black
    G8Footswitch lug 1Black
    G12VOLUME lug 1Black
    G14Output jack sleeveBlack

    Pot lugs are numbered 1, 2, 3 from left to right when you look at the back of the pot with its lugs pointing up.

  11. Wire the footswitch, jacks, and LED

    The footswitch wiring is the same as the Fuzz Face kit's, except that footswitch lug 2 goes to the DRIVE pot instead of the board. The diagram shows Fuzz Face hole names, so use the pad table above for the board end of each wire. Select the diagram to open the full-size image.

    Footswitch wiring: the 3PDT switch's nine lugs, seen from the back, wired to the jacks, LED, battery, and board pads (Fuzz Face hole names)

    1. Check the footswitch

      With your meter on continuity, check that each middle-row lug beeps to exactly one outer lug in its own column. Click the switch and check again: it should now beep to the lug at the other end of the same column.

    2. Wire the footswitch

      • Lug 2 to DRIVE lug 3.
      • Lug 3 to VOLUME lug 2.
      • Lug 5 (middle) to the input jack tip.
      • Lug 6 (middle) to the output jack tip.
      • Lug 8 to lug 9: a short bare jumper. This is the bypass path.
      • Lug 1 already has a wire from the board. Lug 7 stays empty.

    3. Wire the LED

      Solder the LED resistor to the LED's long lead (anode, +), and the wire from pad A16 to the resistor's other end. Solder a wire from the LED's short lead (cathode, −) to footswitch lug 4. Cover the joints with heat-shrink tubing.

    4. Wire the battery

      Solder the battery snap's red lead to pad A14. Solder the black lead to the input jack's ring lug, not to the board. A mono plug in the input jack connects the ring to the sleeve, so the pedal only draws power while a cable is plugged in.

  12. Verify the build

    Before you connect a battery, inspect and test the assembly.

    1. Inspect the copper side

      Check every joint. Joints should be shiny and smooth, with no solder bridging two strips. Most stripboard faults are a solder bridge or a missed cut.

    2. Check for a short

      With no battery connected, measure the resistance between pad A14 (+9 V) and any hole in row G (ground). It must not read close to 0 Ω.

    3. Check the clipping switch

      On continuity, check that pad G6 beeps to F1 with the toggle one way, to F16 the other way, and to neither in the middle.

  13. Check the voltages

    Connect the battery, plug a cable into the input jack, and put the black probe on any hole in row G. With no guitar signal, measure:

    PointExpected (simulated, 2N3904)
    Strip A (+9 V)About 9 V
    Strip B (collector)About 7.3 V (5 to 7.5 V is fine)
    Strip C, columns 4 to 16 (base)About 0.8 V
    Strip D (emitter)About 0.17 V
    Your ChoiceUnderstanding Your Options - R1

    The collector sits high in this circuit, and the exact voltage depends on your transistor's gain. If strip B reads above 7.5 V, replace R1 with 1.5 MΩ or 1 MΩ to bring it down toward the middle of the supply. That gives the stage more room before it clips on its own.

  14. Test it

    Connect your guitar to the input and your amplifier to the output. Start with the amplifier quiet.

    • Click the footswitch until the LED is off. You should hear your clean guitar.
    • Click again. The LED lights and you should hear the distortion.
    • Try all three CLIP positions, and turn DRIVE and VOLUME through their full range.
    CautionThe middle CLIP position is much louder

    With no diodes in circuit, nothing limits the output level. Turn VOLUME down before you switch to the middle position.

  15. Mount it in the case

    Mount the footswitch, both pots, the toggle, both jacks, and the LED bezel, and tighten their nuts. Put standoffs or insulating tape on the copper side of the board, then fit it in the case. Place the battery where its terminals can't touch the board or the switch lugs. Close the case and test again.

    CautionKeep bare metal off the case

    If you line the case with foil tape, any bare lead or joint that touches it causes a short. Ground the foil with a wire to any free hole in row G.

Operating Instructions

The Electra is a simple, bright distortion. DRIVE sets how hard your signal hits the transistor, VOLUME sets the output level, and the CLIP toggle picks the clipping:

  • 1N4148 diodes: the hardest, most compressed distortion, and the quietest.
  • Middle (no diodes): only the transistor clips. The loudest and most open setting.
  • LEDs: between the two. Louder and more open than the 1N4148s.

The toggle's lever connects the middle lug to the lug at the opposite end, so mark which way is which after you test it. The footswitch switches between the effect and true bypass, and the LED is lit when the effect is on. The pedal draws power only while a cable is plugged into the input jack.

Troubleshooting

  • Bypass works, but there's no sound with the effect on: check that the guitar goes into the input (stereo) jack, and that footswitch lug 2 goes to DRIVE lug 3.
  • Collector (strip B) reads close to 9 V: Q1 isn't conducting. Check its pinout and direction, and check R1 and the cut at C3.
  • Collector reads under 1 V: look for a solder bridge between strip B and strip C.
  • One CLIP position sounds lopsided or harsh: one diode in that pair is backwards.
  • The LED position sounds the same as the 1N4148 position: the cut at F8 is missing or bridged.
  • A diode position is as loud as the middle position: that pair's wire to the toggle is loose.
  • The LED doesn't light: the LED is probably backwards. Its short lead goes to footswitch lug 4.