DIY Build: SansAmp Bass Driver V2 Clone

Discovering the Circuit Diagram

I finally built a DIY version of the SansAmp Bass Driver V2, a pedal I had been curious about for a long time.

Late last year, while casually searching online for a schematic, I came across someone who had reverse-engineered the actual unit:。

• Tech 21 SansAmp Bass Driver DI V2 Analysis (Blog in Japanese)

They had posted a KiCAD-drawn schematic, which I immediately downloaded for inspection.

Unlike the original version, the V2 features an expanded EQ section, making it more versatile. Countless YouTube reviews demonstrate the wide tonal range it offers.

Interestingly, the actual Tech21 board is potted in resin to hide the circuitry, but even that was analyzed. It turns out the hidden part is simply a Zener diode clipping circuit, most likely for tube-amp style emulation.

Customized as a Home-Recording Bass Preamp

From the downloaded schematic, I stripped out unnecessary parts like the DI section to repurpose it as a bass preamp for home recording.

• The stock op-amp is TLC2262, but since I couldn’t source it, I substituted a similar rail-to-rail type: TLC2272CP.
• The clipping circuit in the original uses an SMD diode array. I replaced it with standard through-hole 3.3V Zener diodes

DIY Modified Schematic

I based my design on the schematic shared in the above blog, but removed the unnecessary sections:

• DIY SansAmp V2 Modified Schematic (PDF)

PCB Design in KiCAD

I then created a double-sided through-hole PCB in KiCAD. While the real SansAmp uses SMD components, I replaced them with general through-hole parts. I use KiCAD on Mac; though the Mac version has minor quirks with text input compared to Windows, it works fine overall.

For background on my PCB design process, see this earlier article:

• Serious PCB Design for Guitar Pedals Using KiCAD (Blog in Japanese)

First-Power Success!

The reverse-engineered schematic was spot-on. My PCB booted up and worked perfectly on the first try with no errors. One challenge: the design has seven 100k pots, making front-panel wiring a hassle. But by using connector wires, I managed without mistakes.

Sound

• The tone is nearly identical to the YouTube demos of the real V2.
• My Zener diodes differ from the original SMD parts, so clipping character may not be identical—but honestly, which is “correct” is debatable.
• Compared to EQ tweaks in a DAW, this unmistakably delivers the SansAmp character.

DIY Front Panel

I designed the front panel in PowerPoint, printed it on sticker sheet using an inkjet printer, and applied it to the enclosure.

For details on how I make custom pedal labels, see:

• How to Create Custom Pedal Labels (WEB page in Japanese)

Sound Sample — Light Overdrive

Here’s a rhythm track recorded direct-in (line) with light overdrive to add a rock edge:

↓Knob settings at the time of recording:

Tech21 SANSAMP BASS DRIVER DIを探してみる（Amazon）