Lehle GmbH (manufactured by LEHLE in Germany on behalf of RMI) RMI Basswitch IQ DI

The RMI Basswitch IQ DI is an all-in-one bass preamp and central controller: an A/B input switcher, a preamp, a clean booster, a parametric EQ, an FX loop switcher and a DI box in a single unit¹. It was designed by Jacques Ruppert of RMI (Ruppert Musical Instruments) and manufactured, assembled and tested in Germany by Lehle on RMI's behalf²³. Lehle lists it as discontinued: production ended with Jacques Ruppert's retirement at the end of 2019²⁴.

The concept, which Lehle's product page calls a "swiss army knife for bassplayers," came from Ruppert, while the technical side was realized at Lehle using LEHLE True Sound Technology². No Treble's Damian Erskine noted the same idea in his review, calling it a "Swiss Army Knife for Bass Players"⁵.

A bass preamp, A/B switcher and DI in one box

The Basswitch IQ DI has two inputs, feeding channels A and B, so a player can keep two basses plugged in with separate settings dialed in simultaneously⁶¹. Channel A routes through a high-end preamp with a four-band EQ designed specifically for bass⁷. Channel B is a second, independent path, and the unit switches between them, which makes it useful both as a standalone DI and as the master controller of a pedalboard⁶.

The DI section is studio grade, with a pad switch, a pre/post switch and a ground lift switch, and it uses a LEHLE LTMZ transformer for galvanic isolation². The balanced XLR output can go straight to a mixing desk⁶⁷. Premier Guitar's reviewer found it "a cool option for bassists who want to take control of their sound in a variety of situations," whether used standalone or at the heart of a board⁶.

The EQ and level controls

Channel A's EQ is a four-band design with double parametric mids: a knob for each frequency range, plus a volume control⁶⁵. Channel A also has a cut and boost level control for matching volume between the two inputs².

The Mix control blends the FX loop's return with the clean tone, from fully dry to fully wet². Premier Guitar highlighted this as "a Mix control that allows you to blend in an effect with the clean tone," useful for keeping low end clean under a distortion or filter effect⁶. The front panel also carries a large mute button⁶.

Power: 9 to 20V AC or DC

The Basswitch IQ DI accepts any power supply delivering 9 to 20 volts, AC or DC, and polarity is not relevant². Internally the supply is rectified, filtered, stabilized and brought to 18V³. It requires at least 130 mA, and no power supply is included with the unit²⁷.

Pickups, inputs and specifications

Channel A is designed to accommodate both traditional electromagnetic and piezo pickups²¹⁷. Bass Musician Magazine's Eric Parsons noted the switch "to accommodate both traditional electromagnetic or piezo pickups"⁷. Channel B serves as a second input for the instrument¹.

Other published specifications include distortion of 0.005% and a maximum level of 5V RMS (approx. 16 dBu)¹. The manual lists a maximum gain of +/- 15 dB³.

Who made it and who designed it

The Basswitch IQ DI comes from a collaboration. Jacques Ruppert from Luxembourg, head of RMI, was searching for a company to realize his vision of an all-in-one bass preamp, and the technical part was realized at Lehle, combined with independent design by Simon Busse and Lehle True Sound Technology²⁴. Lehle manufactures, assembles and tests the unit in Germany on behalf of RMI²³. Premier Guitar's review also noted the unit carries "Lehle switching technology to boot"⁶.

RMI and Ruppert Musical Instruments are the same company: RMI is the abbreviation, and Ruppert Musical Instruments is the full name used in the press coverage and the manual⁶¹³. Lehle is the German manufacturer behind the build quality and switching.

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