DIY Guitar Pedal PCB: Building an Ibanez SM-7 Smash Box Clone

Introduction

Unlock the iconic sound of the Ibanez SM-7 Smash Box with this comprehensive guide to building your own DIY guitar pedal. This sought-after pedal, known for its rich harmonics and aggressive distortion, has been a staple in the arsenals of renowned guitarists worldwide. Embark on this rewarding project and experience the thrill of crafting your own tone-shaping masterpiece.

Components and Materials

To build your SM-7 clone, you will need:

• PCB: Ibanez SM-7 Smash Box PCB (e.g., PedalPCB SM7-R)
• Capacitors:
  • 47nF ceramic capacitor (C1)
  • 10nF ceramic capacitor (C2)
  • 220pF ceramic capacitor (C3)
  • 1μF electrolytic capacitor (C4)
  • 10μF electrolytic capacitor (C5)
• Resistors:
  • 100Ω resistor (R1)
  • 560Ω resistor (R2)
  • 3.3kΩ resistor (R3)
  • 4.7kΩ resistor (R4)
  • 10kΩ resistor (R5, R6, R7, R8, R9, R10)
• Semiconductors:
  • JFET transistor (J1) (e.g., 2N5457)
  • Diode (D1) (e.g., 1N4001)
  • Operational amplifier (IC1) (e.g., TL072)
• Hardware:
  • Aluminum enclosure
  • DC power jack
  • Footswitch
  • 3PDT switch
  • Knobs (gain, tone, volume)
  • Battery clip (optional)

Assembly

1. Solder the Resistors and Capacitors:
   Begin by soldering the resistors and capacitors onto the PCB. Use a soldering iron with a fine tip and lead-free solder.

2. Install the Semiconductors:
   Next, mount the JFET transistor, diode, and operational amplifier onto their respective locations on the PCB. Ensure proper orientation and solder their connections securely.

   

3. Wire the Knobs and Footswitch:
   Mount the knobs and footswitch onto the enclosure. Connect the wires from the knobs to the corresponding potentiometer terminals on the PCB. Wire the footswitch to the 3PDT switch.

4. Install the DC Power Jack:
   Mount the DC power jack onto the enclosure and connect its terminals to the PCB.

Testing and Calibration

1. Connect and Power On:
   Connect a 9V power supply to the pedal and turn it on.

2. Check Functionality:
   Check if the pedal is working by engaging the footswitch and strumming on your guitar. You should hear a distorted sound.

3. Adjust Gain, Tone, and Volume:
   Use the gain, tone, and volume knobs to adjust the pedal's distortion, EQ, and output level.

4. Tweak Transistor Bias (Optional):
   For advanced users, adjust the transistor's bias voltage by tweaking the value of R1 (100Ω). A higher value will decrease the bias, resulting in a more saturated distortion.

   

Tips and Tricks

• Use High-Quality Components:
  Investing in high-quality capacitors, resistors, and semiconductors will enhance the pedal's sound and reliability.

• Pay Attention to Wiring:
  Make sure all wires are properly connected and insulated to avoid noise and shorts.

• Use a Solder Sucker:
  If you need to remove solder, use a solder sucker to prevent damaging the PCB.

• Experiment with Different JFETs:
  Try out different JFET transistors to explore variations in distortion and gain characteristics.

• Modify for Battery Power:
  If desired, you can modify the pedal to run on a 9V battery by adding a battery clip and disconnecting the DC power jack.

Pros and Cons

Pros:

• Iconic Ibanez SM-7 Smash Box sound
• Versatile distortion with aggressive harmonics
• Relatively simple to build
• Can be customized and modded

Cons:

• Requires some soldering experience
• Can be noisy if not properly assembled
• May not be suitable for every musical style

FAQs

1. What is the difference between a clone and a replica pedal?
   A clone is a pedal that replicates the circuit design of another pedal, while a replica aims to recreate both the sound and aesthetic of the original.

2. Why use a JFET transistor?
   JFETs provide a vintage, warm distortion sound that is characteristic of many tube amplifiers and classic pedals.

3. Can I use a different operational amplifier?
   Yes, you can experiment with different op-amps to achieve variations in tone and gain. Some popular choices include the TL062 and LM308.

4. How can I prevent noise in the pedal?
   Use shielded wires, proper grounding, and high-quality components to minimize noise.

5. What is the best enclosure for the pedal?
   An aluminum enclosure will provide excellent shielding and durability.

6. How do I get the most aggressive distortion from the pedal?
   Turn the gain knob clockwise and tweak the transistor bias by increasing the value of R1.

Funny Stories

• The Lost JFET: Once, while building an SM-7 clone, a builder accidentally dropped a JFET transistor onto the floor. After searching frantically for hours, they finally found it under the refrigerator!

• The Tone-Deaf Distortion: A guitarist built an SM-7 clone but accidentally wired it backward. When they played their guitar through it, the distortion sounded so atrocious that their bandmates couldn't help but laugh.

• The Pedal of Doom: During a gig, a guitarist's SM-7 clone suddenly started emitting a high-pitched squeal. The feedback was so intense that it caused the entire PA system to feedback, resulting in a deafening cacophony that sent the audience running for cover.

Tables

Conclusion

Building your own Ibanez SM-7 Smash Box clone is a rewarding and educational experience. By following these instructions carefully, you can create a high-quality pedal that will deliver the iconic distortion sound sought after by countless guitarists. Whether you are a seasoned builder or a novice enthusiast, this project promises to enhance your understanding of guitar pedals and provide you with a customized weapon for your musical arsenal.