Ruppert Musical Instruments Basswitch IQ DI

The Ruppert Musical Instruments Basswitch IQ DI is a preamp, dual effects looper, A/B switcher and DI pedal for bass, built in Germany by Lehle on behalf of RMI¹². Introduced in January 2011, it was designed as a central controller for a bass rig: No Treble described it as serving as "an A/B input switcher, a preamp, a clean booster, a parametric EQ, an FX loop switcher, and a D.I. box"³. Production ended after Jacques Ruppert retired at the end of 2019, so the unit is now discontinued².

What it does for a bass player

The idea behind the Basswitch IQ DI is to put the whole front end of a bass rig in one box. Two inputs feed channels A and B, so you can plug in two basses with separate settings dialed in simultaneously, or use one bass and jump to channel B for a quick boost or a different EQ and effects setting for another playing style¹⁵. Channel A routes through a high-end preamp with a four-band EQ designed specifically for bass, while Input B bypasses both the preamp and EQ sections⁶. A balanced XLR DI output connects straight to a mixing desk⁶¹.

Premier Guitar's reviewer found the sound "clean and surprisingly warm for its solid-state components"¹.

The controls: two channels, four-band EQ and three footswitches

Channel A carries the preamp and a four-band EQ with a knob for each frequency range, boasting double parametric mids: bass, parametric low-mid, parametric high-mid and treble, plus a volume control¹⁷⁵. Channel A also has a cut and boost level control for balancing volume between the two inputs⁴.

Eric Parsons, reviewing for Bass Musician Magazine, was emphatic about the EQ:

There are three footswitches: an A/B selector to toggle between the two inputs, a large mute button front and center, and a mix loop/boost button⁶¹. The switches are not typical stompbox buttons. Each uses a mushroom-shaped button mechanically and electrically isolated from the internal circuit board, a design Lehle claims gives each switch a lifecycle of 2 million clicks, compared to about twenty thousand for a garden-variety stompbox switch. Parsons found them "dead silent in their operation with no pops or clicks when activated"⁶.

One quirk worth knowing: the EQ knobs sit in the reverse order of what many players expect, with the highs on the left and the lows on the right. Premier Guitar's reviewer noted the inverted controls take some getting used to, but called it "a small price to pay for the peace of mind the Basswitch delivers"¹. The knobs are also flush with the top of the unit, with one side receded into the structure to reduce the possibility of damage⁶.

Power and connections

The Basswitch IQ DI accepts any power supply delivering 9 to 20 volts, AC or DC, at a minimum of 130 mA⁴. The manual explains that polarity is not relevant because the supply is internally rectified, filtered, stabilized and brought to 18V inside the unit⁸. No power supply is included⁶.

Other published specifications from the launch coverage include a frequency range of 20 Hz to 100 kHz, maximum level of 5V RMS (approximately 16 dBu), maximum gain of +/- 15 dB, distortion of 0.005 percent, and a signal-to-noise ratio of -94 dB at 1 kHz, 0 dBu (A weighted)³. Output impedance is listed as 150 Ohms³.

Physically, it is relatively thin, about an inch and a half at its thickest, and about as wide as three Boss pedals placed side by side, weighing just a hair over three pounds¹. The bottom is completely flat with four sturdy rubber feet that can easily be popped in or out¹.

Effects loops: a serial loop and a blendable mix loop

The unit carries two effects loops. One is a passive serial loop for effects like compressors that you may want engaged all the time¹. The second is a switchable loop with a Mix control that lets you blend an effect in with the clean tone, with settings from 0 percent (dry) to 100 percent (wet)¹⁴. If no effects are placed in the mix loop, its switch can function as a clean boost⁶.

The mix loop section adds two problem-solving switches:

• Pre/Post: lets you send the clean tone to the DI while you listen to the effected tone through your amp or headphones¹
• Phase: inverts the phase when the clean signal and the effect return signal cancel each other out¹

History: Jacques Ruppert, Lehle and the end of production

The concept came from Jacques Ruppert, head of RMI in Luxembourg, who was searching for a company to realize his vision of an all-in-one bass preamp. Lehle calls the result a "swiss army knife for bassplayers": the concept was Ruppert's, while the technical part was realized at Lehle True Sound Technology, which manufactured the unit in Germany on behalf of RMI²⁴. Vintage Guitar reported on the launch under the Lehle banner, noting its high-grade components⁷.

The Basswitch IQ DI came out of a collaboration: Jacques Ruppert, head of RMI (Ruppert Musical Instruments), supplied the concept for what one source called a "swiss army knife for bassplayers," while the technical part was realized at Lehle, which manufactured the pedal in Germany on RMI's behalf⁴. Ruppert had been searching for a company to realize his vision of an all-in-one bass preamp, and the design combined his work with independent design by Simon Busse and Lehle True Sound Technology². Production ended when Ruppert retired at the end of 2019, and the pedal is now discontinued².

Production was discontinued due to Jacques Ruppert's retirement at the end of 2019². Lehle's product page now lists the RMI Basswitch IQ DI as discontinued⁴.

What reviewers said

Published reviewers were positive across the board. Premier Guitar's reviewer found the footswitches "very solid and ready to take a healthy dose of not-so-delicate switching," and suggested one improvement: marking the knobs with the same glow-in-the-dark paint used for the Basswitch logo would help in low-light situations¹. Parsons praised the switches, the EQ and the flexibility, noting a street price of about $600⁶, matching the $599 street price Premier Guitar listed¹.

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