Premier Guitar features affiliate links to help support our content. We may earn a commission on any affiliated purchases.

Electro-Harmonix Bass Mono Synth Review

Electro-Harmonix Bass Mono Synth Review

Big, warm, analog synth sounds for your low go.

Recorded direct into Avid Mbox into Logic X using Sandberg T5 with both pickups engaged.
Clip 1: Synth type set to Twin. Dry control at noon, synth control at 2 o’clock, sensitivity at noon, and ctrl knob at 11 o’clock. 80 Hz boosted.
Clip 2: Synth type set to Oblivion. Dry control at noon, synth control at 2 o’clock, sensitivity at noon, and ctrl knob at 11 o’clock. 50 Hz cut and 2 kHz boosted.


Several usable sounds. Basic programmability. Compatibility with an expression pedal.

Slightly picky with tracking.


Electro-Harmonix Bass Mono Synth


Ease of Use:



Reproducing classic analog synth sounds on an electric bass is something I dreamed of as a kid, during my first years as a bassist. But the pedals available at the time never quite hit the spot. I felt they had tracking issues, added lag to the attack, or simply muddied up the tone—the things actual keyboards don’t do. Even though I’ve had some synth pedals that raised my eyebrows and made their way to my pedalboards for various amounts of time, I haven’t found one that stuck. It’s usually only one or two of the preset modes that are even remotely useable, so I usually end up using my “faux” synth-bass chain consisting of a fretless bass, octave pedal, and an envelope filter. So, yes, it was with some skepticism that I checked out the new Bass Mono Synth from EHX, but the majority of my concerns were quickly erased.

Lay It Out
The pedal has an attractive exterior with an original color scheme. The large, cream-white controls are an instant win and their positioning just plain makes sense, with the dry control far to the left. The neighboring “synth” control regulates the level of the synth-y goodness. The sensitivity control operates in conjunction with the LED light to assist a player in getting to a good input level. Many of the 11 synth presets available require the input signal strength to be just right when hitting the effects processor for the pedal to do its best work. The control dial affects a different parameter for each synth type, which is clearly explained in the well-written manual. A custom, programmable user patch is also available foreach of the 11 synth variations available by changing the “type” control.

The moment I plugged my Sandberg TM5 into the pedal and started scrolling through presets and turning knobs, a smile spread across my face.

Zero to Grin in Two Seconds
The moment I plugged my Sandberg TM5 into the pedal and started scrolling through presets and turning knobs, a smile spread across my face. Right away this pedal made me want to play classic, big, simple lines. The “oblivion” setting treated me to a large, all-frequency-filling, vintage-yet-modern sound that can be very useful for EDM-leaning material. The “growl” and “acid” presets needed very minimal tweaking to achieve a bubbly, creamy, and chocolate-y sound that made me want to lay into some Gap Band tunes. Behind the “twin” setting hides a punchy, heavily growling tone that would cut through a wall of competing, thick synth patches playing chords in a band setting. The pedal tracks fairly well, but it does demand you play cleanly for its best performance, since it truly is monophonic. In order to help the pedal along, it’s also crucial to place it at the very beginning of a signal chain.

The Verdict
A pedal will never feel like playing a keyboard, but when carefully tweaked, the sounds oozing out of the Bass Mono Synth will get you through a gig when you need to get close to the real thing. If you are new to synth effects, the Bass Mono Synth is a comprehensive but easy-to-navigate starting point, with more than enough gooey Hershey’s syrup to sweeten up your palette.

Featuring FET instrument inputs, "Enhance" switch, and innovative input stage, this pedal is designed to solve challenges like poor feel, setting levels, and ease of use.

Read MoreShow less

Firebirds came stock with a solid G-logo tailpiece, although Bigsby vibratos were often added.

Photo by George Aslaender

The author’s PX-6131 model is an example of vintage-guitar evolution that offers nostalgic appeal in the modern world—and echoes of AC/DC’s Malcolm Young.

An old catchphrase among vintage dealers used to run: “All Gretsches are transition models.” While their near-constant evolution was considered confusing, today their development history is better understood. This guitar however is a true transition model, built just as the Jet line was undergoing major changes in late 1961.

Read MoreShow less

On her new record with her trio, Molly Miller executes a live-feeling work of structural harmony that mirrors her busy life.

Photo by Anna Azarov

The accomplished guitarist and teacher’s new record, like her lifestyle, is taut and exciting—no more, and certainly no less, than is needed.

Molly Miller, a self-described “high-energy person,” is fully charged by the crack of dawn. When Ischeduled our interview, she opted for the very first slot available—8:30 a.m.—just before her 10 a.m. tennis match!

Read MoreShow less
DØVYDAS & John Bohlinger Busk in Downtown Nashville
DØVYDAS & Bohlinger Busk in Downtown Nashville Before We Give Takamine Guitar & Fishman Amp to Local

Then we give a Takamine guitar & Fishman amp to an up-and-coming Nashville musician.

Music City is always swirling with top-notch musicians performing anywhere they can, so Takamine and Fishman challenged PG's John Bohlinger to take his talents downtown to—gig on the street—where he ran into YouTube sensation DØVYDAS and hands over his gear to rising star Tera Lynne Fister.

Read MoreShow less