The Lehle Basswitch Clean Boost is a compact bass preamp and clean booster made by Ruppert Musical Instruments. The maker describes it as "an all-purpose, super compact high-end bass preamp," and its primary application as a booster with an adjustable EQ1. It sits in the boost family but adds tone shaping that most simple boost pedals leave out, and it is built for bass as much as guitar, alongside other bass pedals and preamp pedals.
The controls
The Basswitch Clean Boost has one footswitch and four controls:
| Control | What it does |
|---|---|
| GAIN | Adjusts the volume of the Clean Boost, with both boost and cut; the neutral position is at 12 o'clock. Maximum gain is +/- 15 dB1 |
| B (Bass) | Targeted cut and boost of the deepest frequencies, designed with the deepest frequencies of bass instruments in mind1 |
| M (Mid) | Boosts and cuts the lower mids1 |
| Treble | Shelving control over the top end1 |
| Footswitch | Activates the booster, switching the Clean Boost on or into straight-through mode1 |
The status LED shows which mode you are in: it turns blue when the Clean Boost comes on and white in bypass mode1. Switching uses Lehle True Sound Technology, which the maker says uses exclusively gold-plated contact relays and/or gold-plated switches1.
Power
The Basswitch Clean Boost runs from 9 to 15 volts AC or DC, which the circuit brings internally to 18 V, and it draws a maximum of 60 mA1.
The Basswitch Clean Boost cannot run on batteries: the manual states that its power consumption is too high to run it satisfactorily on batteries1. Plan a supply output that can deliver up to 60 mA.
Polarity is not a concern either way. The manual states: "Either alternating (AC) or direct current (DC) sources can be used and the polarity is not relevant."1 That makes it unusual among pedals: a standard center-negative supply, a center-positive supply or an AC output all work, as long as the voltage stays within the 9 to 15 V range.
Audio specifications
The maker's manual gives these figures1:
| Specification | Value |
|---|---|
| Frequency range | 30 Hz to 150 kHz (+0/-3 dB) |
| Max. gain | +/- 15 dB |
| Max. level | 15 dBu (with 12 volt power supply) |
| Input impedance | 2 MOhm |
| Output impedance | 150 Ohm |
| Signal-to-noise ratio | -96 dB @ 1 kHz, 0 dBu |
| Distortion | 0.0025 % |
| Bass EQ | +/-17 dB @ 40 Hz (peaking) |
| Mid EQ | +/-13 dB @ 640 Hz (peaking) |
| Treble EQ | +13 dB @ 5 kHz / -13 dB @ 10 kHz (shelving) |
The frequency range reaching 150 kHz and the very low distortion figure reflect its design as a high-end preamp: the maker positions it for matching signal levels across a rig rather than coloring the tone, with the EQ sections there when you want targeted cut or boost1.
Connections and dimensions
The input, labeled IN, is for the instrument and is designed to accept active and passive instruments, so an active bass with an onboard preamp plugs in without any setting changes1. The output, labeled OUT, connects to a bass amp, a power amplifier or an active monitor1.
| Physical | Value |
|---|---|
| Length | 14.9 cm |
| Width | 6.0 cm |
| Overall height | 4.4 cm |
| Weight | 390 g |
The Lehle RMI Basswitch Clean Boost measures 14.9 cm long, 6.0 cm wide and 4.4 cm in overall height, and weighs 390 g1. Its input impedance is 2 MOhm and its output impedance is 150 Ohm1.
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Questions
Can the Lehle Basswitch run on a battery?
No. The maker's manual states that the power consumption of the Basswitch Clean Boost is too high to run it satisfactorily on batteries, so it needs an external power supply. It takes 9 to 15 volts AC or DC through a standard 5.5 x 2.1 mm connector and draws a maximum of 60 mA, which rules out battery power entirely.
Does the Basswitch work with active basses?
Yes. The input is designed to accept active and passive instruments, so you can plug an active bass with an onboard preamp or a passive instrument straight in. The output is intended for a bass amp, a power amplifier or an active monitor, and the input impedance is 2 MOhm with an output impedance of 150 Ohm.
Does power polarity matter on the Lehle Basswitch?
No. According to the manual, either alternating current (AC) or direct current (DC) sources can be used and the polarity is not relevant. That means a standard center-negative pedal supply, a center-positive supply or an AC output all work, as long as the voltage is between 9 and 15 volts.
How much boost and cut does the Gain control give?
The Gain control adjusts the volume of the Clean Boost and can both boost and cut the signal, with the neutral position at 12 o'clock. The maximum gain is plus or minus 15 dB, which lets you match the unit's output level to the rest of a rig in either direction.
What does the LED color on the Basswitch mean?
The status LED shows which mode the unit is in: it turns blue when the Clean Boost is on and white in bypass mode, which the manual calls straight-through mode. The switching itself uses Lehle True Sound Technology, meaning gold-plated contact relays and gold-plated switches carry the signal.
Where is the Lehle Basswitch made?
The manual states that the Basswitch Clean Boost is manufactured, assembled and tested in Germany to the highest quality standards. The maker is Ruppert Musical Instruments, which builds under the Lehle name, with the company address given as Schouweiler in Luxembourg.
Sources (1)
- Lehle-RMI-Basswitch-Clean-Boost_Manual_EN.pdf, Ruppert Musical Instruments, 2023
