The Lehle Basswitch Sonic Spark is a bass pedal that combines a harmonic overtone generator and a complex EQ section with a high-end preamp in one unit. Lehle describes its primary application as sonic enhancing: the pedal generates harmonic overtones, blends them with your direct bass signal, and matches levels on the way out. Lehle says it creates "a very alive and characteristic sound like a high quality tube amp with only a few controls"1.
It sits among bass pedals as a sonic enhancer and preamp rather than a distortion or overdrive box, and it is built in Germany: the manual states it is "manufactured, assembled and tested in Germany to the highest quality standards"1.
The controls
The Sonic Spark keeps its front panel to three knobs and a footswitch1.
| Control | What it does |
|---|---|
| Enhance | Adjusts the amount of overtones generated by the Basswitch Sonic Spark |
| Intensity | Sets the ratio between the direct sound and the Sonic Spark sound, progressively from 0% to 100% of the overall sound |
| GAIN | Boosts and cuts the signal to match levels, with the neutral position at 12 o'clock |
| Footswitch | Pressing it turns the Sonic Spark on or into "straight through" mode |
The status LED shows which mode you are in: it lights up blue when the Sonic Spark is activated and white in bypass mode1. Lehle suggests "straight through" mode (LED white) when the pedal is used as a sonic expander upstream of a bass amp, and activated mode (LED blue) when it feeds a power amp, active monitor, active bass cab or in-ear system1.
The input is the standard input for all instruments and is designed to accept active and passive instruments, so a passive bass plugs straight in. The output connects to your bass amp, power amplifier or active monitor1.
Power: 9 to 15 volts AC or DC
The Sonic Spark is unusually flexible about power. Either alternating current (AC) or direct current (DC) sources can be used, and the polarity is not relevant, so a center-negative supply is not required. The incoming voltage is internally rectified, filtered, stabilised and then brought to 18 volts1.
The pedal needs a supply of 9 to 15 volts AC or DC, delivering at most 60 mA at 9 V DC or 65 mA at 15 V DC, with the voltage brought internally to 18 V. A daisy-chain output shared with other pedals may not cover that current draw.
Current draw depends on the supply voltage1:
| Supply voltage | Maximum current draw |
|---|---|
| 9 V DC | max. 60 mA |
| 15 V DC | max. 65 mA |
Buffer and bypass: Lehle True Sound Technology
The Sonic Spark does not switch in the plain true-bypass sense. Lehle's "True Sound Technology" combines a very high-quality buffer at the beginning of the chain with true-bypass-equipped effects downstream. For switching, it uses exclusively gold-plated contact relays and/or gold-plated switches1.
The buffers are designed to effortlessly handle signals reaching the megahertz range, and the output frequency bandwidth is limited to the audible frequency range to prevent HF interference1. For a player, that means the pedal can sit at the front of a board, buffer the signal for everything after it, and still pass a clean signal in "straight through" mode.
Videos
Jacques channel
Bass Whisperer TV
jo ku
Questions
Can the Lehle Basswitch Sonic Spark run on AC power?
Yes. The manual states that either alternating current (AC) or direct current (DC) sources can be used, in the range of 9 to 15 volts. The incoming supply is internally rectified, filtered and stabilised, then brought to 18 volts inside the pedal. The connector is a standard 5.5 x 2.1 mm barrel, and the polarity of the supply is not relevant.
Does the Lehle Basswitch Sonic Spark work with passive basses?
Yes. The input is designed to accept both active and passive instruments, so a standard passive bass plugs straight in. Because the pedal buffers the signal at the start of the chain, it can also drive effects downstream and feed a bass amp, a power amplifier or an active monitor from its output.
Does polarity matter with the Basswitch Sonic Spark power supply?
No. According to the manual, the polarity of the power supply is not relevant, and either AC or DC sources can be used. That is unusual among pedals and means a center-negative supply is not required, though the supply must deliver at least 65 mA at 9 to 15 volts.
What does the Enhance knob do?
The Enhance control adjusts the amount of overtones generated by the Basswitch Sonic Spark. It is the pedal's harmonic overtone generator control, so it sets how much added harmonic content is blended into the bass signal, working alongside the Intensity control that sets the ratio between the direct sound and the Sonic Spark sound.
What do the blue and white LED colors mean?
The status LED lights up blue when the Sonic Spark is activated and white in bypass mode, which Lehle calls 'straight through' mode. The manual suggests straight through mode when the pedal sits upstream of a bass amp, and activated mode when it feeds a power amp, active monitor, active bass cab or in-ear system.
Is the Lehle Basswitch Sonic Spark true bypass?
Not in the plain sense. Lehle's True Sound Technology combines a very high-quality buffer at the beginning of the chain with true-bypass-equipped effects downstream, using exclusively gold-plated contact relays and gold-plated switches for switching. The buffers are designed to handle signals reaching the megahertz range, with the output bandwidth limited to the audible range to prevent HF interference.
Sources (1)
- Lehle-RMI-Basswitch-Sonic-Spark_Manual_EN.pdf, Ruppert Musical Instruments, 2023
