Do It Yourself

Build Your Own Tricked-Out Electra Distortion

  • By Nicholas Kula @tonereport
  • August 05, 2016
  • 6 Comments

When you think of classic dirt pedals, what comes to mind? Tube Screamers? Fuzz Faces? Big Muffs? Yes, I’d agree. However, I’d throw my hat into a different ring: the Electra Distortion. Though some have never heard of such a pedal, it could very well be because its genesis never existed in stompbox format.

The original Electra Distortion was an onboard effect, cobbled together with a slew of low-quality effects and then shoehorned into the cavity of Electra MPC guitars. Before Akai seized ownership of that acronym, MPC stood for “Modular Powered Circuits” and was to be Electra’s big contribution to the musical landscape. The entire system was powered with cartridges, which players could swap out at their leisure.

While the guitars never really took off, someone eventually realized that the distortion circuit was the only salvageable part of the entire guitar, then known as “power overdrive” in Electra’s lore. While the other circuits were passable at best, the Power Overdrive, colloquially known in this age as “Distortion,” was passable at worst. At best, it kicked ass. And when people cracked open the cartridge to discover the most barren of landscapes—a sparse tumbleweed-laden circuit board with only a few blobs of material here and there.

This was the Electra Distortion—a powerhouse of tone represented by a thimbleful of components. The circuit spread like wildfire among pedal enthusiasts, and today, it’s the basis of many popular boutique boxes. Its simplicity lends itself to easy modding—even a slight value change can have a drastic effect on the circuit in both sonics and reactance. And since the circuit contains a set of clipping diodes, the possibilities are near-endless.

With the power of DIY, we will explore many of these possibilities in one pedal. By using rotary switches, we will create an Electra Distortion with 30 different settings. And because the original didn’t contain any knobs, we will add volume and distortion controls. Are you excited? I sure am!

But first, the disclaimer: Neither I, nor Tone Report Weekly bears any responsibility for any kind of personal or property damage that may occur as a result of the instructions provided herein. Legal mumbo-jumbo aside, we ask that readers be familiar with a soldering iron and its accompanying safety procedures before trying anything listed here. Furthermore, if you fire the pedal up and it does not work, it will need troubleshooting. Assuming the components are not damaged, the pedal will work. I built this very unit according to these instructions and it fired up, first shot, so I know the instructions are correct.

This marks our first time working with rotary switches—they can be a little tricky. The type we are using are Alpha brand break-before-make (meaning they break the current connection before making the new one) which have a definitive starting and stopping point, unlike make-before-break, which spin indefinitely. Each rotary switch has 12 lugs, which are numbered on the underside, along with a “common” lug (which is in the center). The switches work by connecting the common lug to each numbered lug as you turn the knob. In position 1, “1” will be connected to the common lug, and in the next position, “2” and common will be connected, and so on. Each switch comes with a washer that has a “tooth” on it, and you can select how many positions you want the switch to have by inserting the tooth into the corresponding hole on the top. Be careful when mounting the switch to the enclosure, as the washer can slip, and the “tooth” can pop out and end up in a different hole. Always make sure the switch is turned all the way to the left before inserting the toothed washer.

With that said, here’s what you need to build the circuit board:

Resistors:
1x 680 ohm
1x 47k
1x 2.2m
Capacitors:
Note: you can use any capacitors here that you want, all of them besides one 100nF cap are going to be controlled by the rotary. 100nF is the stock Electra value.
1x 10nF (0.01uF)
1x 22nF (0.022uF)
1x 47nF (0.047nF)
2x 100nF (0.1uF)
1x 220nF (0.22uF)
1x 1uF (if using an electrolytic or tantalum capacitor, make sure the positive side is facing down)
Semiconductors:
Note, much like the capacitors, all the diodes are going to be wired to the rotary. D1 and D2 are the stock diodes, but feel free to use any diodes you want for the rest.
1x 1n914
1x 1n34a
2x 3mm red LED
2x BAT41
2x 1n4148
1x 2n3904 (feel free to experiment with other transistors such as 2n5089 and MPSA18)
Potentiometers:
1x 500kA (logarithmic)
1x 100kA (logarithmic)
Miscellaneous:
1x piece of Veroboard (stripboard), cut to specs in the diagram
2x 1P12T (12 position) break-before-make rotary switches
Wire

Ok, let’s wire this thing up!

Step 1: Insert the three resistors, bend out the leads and solder them in. Clip the leads and save them, you’ll use them all; put the longest one off to the side.

Step 2: Using the remaining five leads, form the jumper wires and solder them in.

Step 3: Because the diodes are the same height as the resistors, we’ll do those next. Again, don’t feel bound to my choices, try different colors of LEDs or other types altogether. Insert them, bend the leads and solder them in, clipping the leads when done.

Step 4: Insert the capacitors and transistor, solder them in. If not using a 2n3904, make absolutely sure that the transistor is in there correctly by Googling your chosen transistor’s “pinout.” Be sure the collector is on top, base is in the middle and emitter is on the bottom.

Step 5: Prepare the rotary switches. They will have a small nub of plastic on the top edge near the washer, shear this off. Turn the switch shaft all the way counter-clockwise, then insert the “tooth” of the washer in slot “5” on one switch, and slot “6” on the other, then tighten down the nuts. Note that we only have four diode sets, but we will use the fifth position as a “no diodes” selection.

Step 6: Wire the switches and potentiometers to the board. Make sure that you’re soldering the wires to the correct rotary terminals (they are labeled underneath). Once everything is soldered, feel free to cut off the remaining leads on the switches, including position “5” on the diodes rotary (we don’t need to connect it to anything, so we don’t need the lug).

STOP! Make sure, using the continuity setting on your multimeter, test for continuity across all cuts and adjacent rows. This is an easy way to find faults before mounting the circuit. Note that some adjacent rows may be connected on purpose on the component side (rows C and D, J and K). If you don’t have a multimeter, make extra sure that there is a clean cut between holes and no solder joining two adjacent rows.

And now, the enclosure! You’ll need the following:

1x 125B enclosure, drilled for four knobs (make sure to account for the rotary switches), two jacks, one power jack, one switch, one LED
2x ¼” mono jacks
1x DC power jack
1x 3PDT latching footswitch
1x LED
1x 2.2k resistor
1x LED bezel
4x knobs

Step 1: Mount the hardware: the switch, LED, and all jacks.

Step 2: Use the leftover lead from the board instructions and make the connection on the switch. Solder the center lug. Note: I mirrored the switch wiring to accommodate my LED. Run a wire from the grounded lugs on the footswitch to the negative lug on the DC jack and solder the switch lugs. Run a wire from the DC negative lug to the sleeve lug of the input jack. Solder the negative DC lug, leaving the input jack sleeve lug unsoldered. Thread the negative leg from the LED into the appropriate switch lug.

Step 3: Wire the tip lugs of the jacks to the appropriate lugs on the footswitch. Solder them all in.

Step 4: Wrap one leg of the resistor around the positive leg of the LED, and wrap a wire around the other leg, and solder both sides of the resistor. Wire the other end into both positive lugs of the DC jack. Solder one of them, leaving the other one unsoldered.

Step 5: Holding it upright, insert the board, and make sure the toothed washer on the rotary switches is in the correct position. Be very careful not to rattle the rotary switches and knock the toothed washers out. Place any kind of insulation you need across the backs of the rotary switches so that the board doesn’t touch the rotary lugs. Wire the ground wire from the board into the unsoldered input jack sleeve lug, and the power wire into the unsoldered DC jack positive lug. Solder them in.

Step 6: Enjoy the fruits of your labor!

So, how does it sound? The Electra Distortion is a truly great circuit, and the stock sound is a very pleasant low-gain overdrive, that sounds very open, with a subtle tube-like compression. This slight compression is due to the asymmetrical diode arrangement, and turning the rotary switches offers up a ton of different options, which work best with distortion maxed. The no-diodes setting works as a supreme, slightly-colored boost that can integrate well into literally any rig on the planet. Here’s a sample of our own Andy playing the Electra across many settings on his Deluxe Reverb reissue with his Redtail Strat.

Until next time, up the irons!

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6 Comments

  1. Scott Anderson

    where is that sample video?

  2. Jan

    Where is video?

  3. Colin J

    Still missing video

  4. Kevin McCarthy

    It says in the directions to cut the stripboard according to the diagram, yet it does not say whether it is in inches, centimeters, millimeters. It’s really kinda hard to know how much to cut without it actually saying the perimeter.

  5. Jim D.

    @Kevin McCarthy - It’s 1.6” by 1.2”. Count the holes. Stripboard holes are on 0.1” centers.

  6. Tillio DeBernardi

    Could someone possibly explain a way to wire this sans rotary switches? I’m trying to put one inside a guitar and there’s no room for rotatory switches