The Lehle RMI Clean Boost is a compact preamp pedal that combines the boost function of the Basswitch IQ DI with a 3-band EQ voiced especially for a clean sound. Lehle specifies a gain adjustment of plus or minus 15 dB, so it can lift a solo or trim a hot signal, and the treble control combines passive high frequency reduction with an active high frequency boost. Lehle lists the pedal as discontinued on its own product page.1
What it does to your sound
Lehle describes the pedal as consigning "a wonderfully tidy soundscape and your instrument will receive a new sonic shine."1 The 3-band EQ is voiced for a clean sound, and the treble control works in two directions at once: passive high frequency reduction and active high frequency boost.1 Because the gain stage covers plus and minus 15 dB, the pedal can sit on a board as a level set and tone shaper as well as a solo booster, which places it among boost pedals with onboard equalization.1
Bass Musician Magazine's review of the RMI pedals says of the Classic Boost: "Like all the RMI pedals, the Classic Boost offers a wide range of tones available via the 3 band EQ and the gain control."2
Circuit and switching
Lehle describes the signal path as running "from the discrete JFET input stage, up to the switching via gold-plated relais," using the company's LEHLE True Sound Technology.1 Wolf's review puts the same features in a player's terms: "Gold plated relays, loss-free silent footswitches, ultra smooth taper pots, and a discrete JFET input stage" all contribute to the design.2 Relay switching of this kind is also found on switching pedals, where silent, loss-free switching is the main selling point.
The design elements Lehle and Wolf both point to:
- Discrete JFET input stage12
- Switching via gold-plated relays12
- Loss-free silent footswitches2
- Ultra smooth taper pots2
- LEHLE True Sound Technology1
Power
The pedal is unusual in accepting AC as well as DC. Lehle says it "works internally with 18 V, but is content with all power supplies between 9 - 15 V AC or DC."1 Wolf's review explains the reason for the internal voltage: "The pedals will accept any 9-15 volt AC or DC power supply, but internally, the voltage is rectified up to 18V, for better headroom."2
The pedal is discontinued, so it turns up on the used market rather than as new stock. Check the power requirement marked on the unit before pairing it with a supply, since it differs from a standard pedal supply.1
Related Lehle pedals
The RMI Clean Boost is designed to work alongside other gear in the range: Lehle says it "can be teamed up with the BASSWITCH IQ DI for more options or work as a compact standalone preamp."1 Related pedals in the company's lineup include the Lehle Basswitch Clean Boost, the Lehle RMI Basswitch Classic Boost and the Lehle Julian.3
Questions
Is the Lehle RMI Clean Boost discontinued?
Yes. Lehle's own product page lists the RMI Clean Boost as discontinued. The company describes it as a compact preamp that combines the boost function of the Basswitch IQ DI with a 3-band EQ voiced for a clean sound, and it can still be found secondhand. Players looking at current Lehle boost options can look at related pedals such as the Basswitch Clean Boost or the Lehle Julian.
How much boost does the Lehle RMI Clean Boost give?
Lehle specifies a gain adjustment of plus or minus 15 dB, so the pedal can cut as well as boost. That range comes from the Basswitch Clean Boost circuit on which the pedal is based. Reviewing the related RMI pedals for Bass Musician Magazine, Jake Wolf noted that the 3-band EQ and gain control together offer a wide range of tones.
Can the Lehle RMI Clean Boost run on AC power?
Yes. Lehle says the pedal works internally with 18 V but is content with any power supply between 9 and 15 V, AC or DC. The AC option is unusual among compact pedals and means many standard DC supplies will also work. Jake Wolf's review of the RMI pedals explains that the incoming voltage is rectified internally up to 18 V for better headroom.
How is the Lehle RMI Clean Boost related to the Basswitch IQ?
Lehle describes the RMI Clean Boost as combining the boost function of the Basswitch IQ DI with a 3-band EQ that has been especially voiced for a clean sound. The pedal can be teamed up with the Basswitch IQ DI for more options or work as a compact standalone preamp in front of an active setup.
Does the Lehle RMI Clean Boost use a JFET input stage?
Yes. Lehle's product page describes a signal path starting from a discrete JFET input stage, up to switching via gold-plated relays, using the company's LEHLE True Sound Technology. Jake Wolf's review of the RMI pedals adds that gold-plated relays, loss-free silent footswitches, ultra smooth taper pots and the discrete JFET input stage all contribute to the design.
Sources (3)
- RMI CLEAN BOOST (DISCONTINUED), Lehle GmbH
- RMI Sonic Spark, Clean Boost, and Classic Boost Reviews, Bass Musician Magazine, 2016-07-17
- Lehle Releases the Julian Parametric Booster, premierguitar.com, 2013-10-04
