How to Modify a Boss DS-1 Distortion Pedal

A few modifications can alter the sound of the DS-1 distortion pedal.

The Boss DS-1 is a classic distortion pedal. Introduced in 1978 and still in production today, it's been used by Joe Satriani, Steve Vai, John Petrucci, Joe Perry and Kurt Cobain, but many prominent DS-1 users weren't content with the pedal in stock form. Modifying the DS-1 has been a tradition for years --- a few simple component changes can manipulate the tone, amount and quality of its distortion.

Things You'll Need

• Soldering iron
• Solder
• Desolder pump
• Clean cloth and/or sponge
• Isopropilic alcohol
• Wrenches (1/2 and 7/16 inch)
• 3mm LED
• Various metal film or polyester film capacitors and resistors

Instructions

Disassemble the Pedal

1. Remove the battery and make sure the pedal is unplugged.

2. Pry off the three knobs on the front of the pedal. Use a flat-head screwdriver if necessary.

3. Remove the nuts holding the tone, distortion and level potentiometers in place.

4. Remove the nuts holding the input and output jacks in place.

5. Turn the pedal over and unscrew the four screws holding the back plate in place. Remove the back plate.

6. Pull the circuit board up slightly and push the power jack out of its slot.

7. Remove the screw holding the LED in place.

8. Desolder the black and purple wires from the footswitch.

9. Remove the circuit board, pots, jacks, battery clip and LED from the pedal housing.

How to Replace a Component

1. Heat a solder joint with the soldering iron.

2. Press the desoldering pump to the joint and activate the pump, once the solder has liquefied. The solder will be sucked up into the pump. Repeat if necessary to adequately clean the joint.

3. Clean the joint with isopropilic alcohol on a soft cloth or sponge.

4. Repeat steps 1 through 3 for the other side of the component.

5. Pull out the old component.

6. Coat each end of the new component, lightly and quickly, with a thin later of solder by applying a small amount of solder to the tip of the soldering iron and then pressing it against the leads of the component. Pre-coating components in this way will help prevent cold solder joints.

7. Insert the new component into the circuit board. Pay attention to the polarity of the component, if necessary. Some capacitors and LEDs are polarized and will behave differently if the positive and negative leads are switched. The circuit board may have polarity markings next to the component.

8. Heat the joint with the soldering iron for a few seconds, and then apply solder to the joint. Apply as little solder as necessary to firmly connect the two components.

9. Remove the soldering iron and solder. Make sure that no part of the joint moves as you do so, as that will compromise the strength of the joint.

Change Specific Components

1. Change the value of resistor R7 to a higher value for more gain or a lower value for less gain and less lower frequency fuzz. R7 controls the amount of gain in the pedal's first gain stage.

2. Decrease the value of capacitor C3 to filter out low frequencies, resulting in a tighter sound. Use value between .01µf and .033µf, depending on how much low end you'd like to filter.

3. Change capacitor C4 to 250pF for a little more presence, if desired. Alternatively, change capacitor C10 to a higher value for less high end. Try a value between .015µF for a slight decrease and .047µF for a significant one.

4. Change capacitors C5 and C9 to 1µF for more bass response.

5. Connect each diode to another of the same type for a grittier distortion. Wire them in series, placing two diodes in place of each original one. Diode D4 is a 1N4148 and D5 is a 1N4001. Alternatively, replace D5 with an LED for a lighter, more complex distortion.

6. Change resistor R13 to 1k and capacitor C8 to 1µf for more gain.

7. Adjust the values of capacitors C11 and C12 in the tone circuit for less of a scooped midrange sound. Decrease C12 to .068µf to reduce the amount of bass, and increase the value of C11 to .047µf or higher for less treble.

8. Increase the value of resistor R17 to 10k or 15k for a more balanced treble response in the tone circuit, and decrease the value of R16 to 4.7k or 1k for a more balanced bass response in the tone circuit.

Tips & Warnings

• Modifying pedals is all about sculpting the sound to suit your personal taste, so use your own judgment in deciding which changes to make and what values to use. It may take some experimentation to find just the right values for you.

• Make sure there is no electricity flowing through a circuit before working on it.

• Take care when operating a soldering iron not to touch the tip to anything other than the circuit board. The tip will become extremely hot and will remain hot for some time after it's been turned off.

References

• Premier Guitar: Boss DS-1 Mods
• Kubton: DS-1 Star Wars Mod & Schematic