SansAmp Bass Driver V2 – Signal Flow and EQ Characteristics

My Interpretation of the SansAmp V2 Schematic

Based on the schematic published on the blog by ”Kanen Gomi Bako(Japanese)", I built my own version of the SansAmp V2. While studying the circuit, I tried to understand how the tone-shaping works.

Note: This is my personal interpretation, not an official analysis.

• (Reference)DIY Build: SansAmp Bass Driver V2 Clone

Bass Amp Emulation + DI

From the schematic, the signal flow seems to look like the diagram above. One path emulates the bass amp/cabinet speaker, while another carries the direct signal. These two are blended together with the BLEND control.

Smooth Overdrive with a Simple Clipping Stage

The clipping stage uses a pair of 3.3V Zener diodes in opposition. When you increase DRIVE, the sound develops a pleasant, moderate distortion, emulating the feel of a tube bass preamp.

↑ (Photo) Cabinet “smiley-curve” filter right after the clipper (measured with REW on my DIY SansAmp V2)

Cabinet Emulation Filter

After the clipper, the signal goes through a filter with a strong dip around 700 Hz. This is what gives SansAmp its signature scooped “smiley” tone.

Similar to Marshall cabinets, many guitar and bass speaker cabinets naturally roll off above ~6 kHz and exhibit a mild dip around 800 Hz in the mids.

The SansAmp filter is much more extreme, producing a very scooped, growly tone. By adjusting the BLEND, you can mix in just enough of this character, ranging from refined to downright nasty.

↑ (Photo) EQ response measured on my DIY SansAmp V2 using REW

The EQ Stage

At the end of the chain, you have a Bass, Mid, and Treble EQ. Bass and Mid can switch their center frequencies. Nothing unusual here – it’s a fairly standard EQ section.

Sample – Lightly Driven Amp Tone

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

↓ (Photo) Knob positions during the sample recording

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