RMI Classic Boost

The RMI Classic Boost is a compact bass preamp that combines the boost circuit from the BASSWITCH IQ DI with a 3-band EQ voiced especially for vintage basses¹. It sits in the boost pedal family, but it is really three tools in one box: a booster with an adjustable EQ, a stand-alone preamp, and a tone shaper for passive instruments. Lehle lists it as discontinued¹.

The design brief was specific. As the maker puts it:

The manual describes the same idea in its own words, calling it a "high-end bass preamp gently voiced for passive P, JJ and PJ type basses"². For a player with a passive Precision or Jazz-style bass looking to add gain and EQ shaping without changing the instrument's basic character, that is the niche this pedal was built for.

What it does and how it sounds

The primary application, per the manual, is as a booster with an adjustable EQ². The gain control adjusts the volume of the unit, boosting or cutting the signal, with a neutral position at 12 o'clock and a maximum of +/-15 dB². The maker also specifies a dynamic range of over 110 dB with very little noise, which it describes as more than studio standard¹.

The EQ is a 3-band design. The bass control gives +15/-11 dB at 45 Hz on a peaking curve²¹. The treble control is unusual: it combines a passive high-frequency reduction with an active high-frequency boost, so it can cut or lift the top end from a single knob¹.

Bass Musician Magazine's Jake Wolf reviewed it in 2016 alongside the RMI Clean Boost and Sonic Spark, and found the Classic Boost had "a little more shape to its tone profile" than the Clean Boost, designed to complement passive or traditional style basses³. He also wrote:

How it compares with other boost pedals

Against a straightforward clean boost like the RMI Clean Boost, the Classic Boost trades some neutrality for EQ shaping, which is the point for passive basses³. Against a guitar-oriented boost with EQ such as the Xotic RC Booster Classic, the differences are clear from the makers' own specs: the Xotic offers a 2-band active EQ of +/-15 dB and a 20 dB+ clean boost⁴, while the RMI gives a 3-band EQ voiced for bass frequencies, with the bass band centered at 45 Hz²¹. The Xotic runs on 9 to 18 V DC only⁵; the RMI accepts AC as well, which matters on boards powered by AC supplies.

Power and connections

The Classic Boost is flexible about power. It works internally at 18 V but accepts any external supply between 9 and 15 V, AC or DC¹. The manual calls for a supply delivering at least 60 mA; the input is internally rectified, filtered, stabilized and brought up to 18 V².

Build and board mounting

The maker describes an extremely robust construction with protected controls and an indestructible switching mechanism, built around LEHLE True Sound Technology with a discrete JFET input stage and gold-plated relay switching¹. For pedalboard use, the manual notes the ultra-flat base and removable rubber feet, which allow the unit to be attached securely with Velcro².

Who makes it

The product page lists Lehle GmbH as the manufacturer¹. The manual carries the name Ruppert Musical Instruments, of Schouweiler, Luxembourg, the builder behind the RMI (Ruppert Musical Instruments) Basswitch line². The two names reflect the same operation as presented in each document.

Questions