How to DIY ROSS & SD9 Guitar Pedals?

If you're curious about how to DIY your own single-effect pedal, keep reading!

The circuitry isn't too complicated; most designs use a single op-amp channel. Today, we'll be building two effect pedals: the ROSS DISTORTION and the SD9 (IBANEZ SONIC DISTORTION). The schematics are provided below.

I.  Prepare the Enclosure

Start by selecting an appropriately sized enclosure. Ensure that the 6.25mm audio jacks and the latching power button fit well.

II.  Drill Holes for Switches

Drill two holes in the middle of the enclosure to install two single-pole double-throw (SPDT) switches. These switches will allow you to toggle the power and input/output between the two effects. Make the hole diameter slightly larger than the switch's mounting size. Here, we're using a card as a mounting base for a second installation.

III.  Install the LEDs

There are two spots for LEDs to indicate the power status of each effect pedal.

IV.  Position the Potentiometers

Drill holes for the potentiometers, with a diameter of 6.5mm. 

Use a piece of paper as a guide to align the potentiometers correctly. From left to right, these will correspond to the GAIN and VOLUME for the ROSS, and DRIVE, TONE, and VOLUME for the SD9.

V.   Install the Knobs

Attach the knobs to the potentiometers. 

During the later stages of testing, you might want to adjust the wiring of the potentiometers to ensure that turning them counterclockwise decreases and clockwise increases the values. Use terminal blocks and a 7805 voltage regulator for the LED power indicator on the latching power switch.

VI.  Wiring the Potentiometers

Solder the wires to the potentiometers.

VII. Power Supply Wiring

Set up the power supply wiring. With the use of a perforated board, you have the flexibility to solder and test as you go.

VIII. Finish the ROSS Build

Complete the ROSS distortion pedal.

IX.  Continue with the SD9

Proceed with the SD9 build. 

Since we're using a lot of surface-mount components on an already populated perforated board, there will be quite a few flying leads.

Take a closer look at the JRC4558 op-amp.

X.  Testing the Sound

1st string open, switch to ROSS: Observe the waveform. As you release the string, the amplitude decreases and the waveform changes.

2nd string open...

3rd string open...

4th string open...

5th string open...

6th string open...

Measure the voltages at various points in the op-amp circuit with no input or output.

XI.  Final Assembly

After assembly, all units work well together.

XII. Power Button Pressed

Switch to ROSS.

Switch to SD9.

XIII. Conclusion

Both distortion effects provide a standard sound. Under heavy chords, you won't get that metal, explosive feel, but they're great for regular solos.