E.W.S. Tri-Logic Bass Preamp II

E.W.S.’S UPDATED TAKE ON THE discontinued Xotic Tri-Logic Bass Preamp, the Tri-Logic Bass Preamp II, is an active 3-band EQ with 20dB of boost.



E.W.S.’S UPDATED TAKE ON THE discontinued Xotic Tri-Logic Bass Preamp, the Tri-Logic Bass Preamp II, is an active 3-band EQ with 20dB of boost. In addition to controls for VOLUME, GAIN, and three bands of EQ (all with center detents), this small stompbox features switches on the sides for adjusting impedance and selecting midrange frequencies. The Tri-Logic isn’t a preamp in the literal sense; it just doesn’t have enough juice to properly drive a power amp, making it best suited as the first device in a bass’s signal chain.

In hand, the pedal feels solid, especially for its size. As a pedal builder and tinkerer myself, my first move was to look inside. The Tri-Logic’s guts are a modern feat of pedal engineering. The pots, jacks, and switches are all mounted directly to the enclosure. The circuit board, which is tiny and efficient, it also mounted to the case with a metal standoff. This is a nice touch, especially in a world where many pedal makers attach the circuit board with adhesive, or worse, just leave them hanging in the case, barely supported by wiring. Somehow, the pedal also fits two 9-volt batteries. The Tri-Logic can also operate with a 9-volt AC adapter, but 18 volts (battery or DC) provides the pedal increased headroom.

On the less flattering side, the knobs feel a bit cheap, and the power jack is on the side below the instrument input, a layout I feel makes for poor ergonomics. A final nit pick: the Comic Sans font. Come on—this isn’t announcing a Friday-afternoon party on the office bulletin board, this is for musicians. We’re still supposed to be cool, right?

Of course, the most important consideration is sound. This is a very clean and classy pedal, with an EQ voiced at pleasant frequencies. Except with the treble at extremely high settings, I didn’t hear any unwanted noise. Though it got a little rough around the edges when set high, the GAIN control is not a distortion or overdrive; it’s perhaps better thought of as “boost” or “warmth.” The VOLUME control reached unity gain between 3 and 5 o’clock when GAIN was all the way down.

With a Fender Deluxe Active Jazz Bass, the pedal’s EQ seemed to be a duplication of the bass’s internal EQ. It this case, I had fun using the pedal to engage temporary EQ shifts. It worked for special-effect dub sounds and mid boosts for leads or lines I wanted to pop out. When I plugged in a passive bass (an old Hagstrom), the pedal functioned wonderfully as outboard active electronics, lending an otherwise dull bass a clear punch. This pedal could be a secret weapon to breathe life into a less-thanstellar instrument, or to add some zazz when playing through a mediocre amp. I also hooked up the Tri-Logic to an upright with an under-bridge pickup, running direct to a PA. It performed very well, and was perhaps my favorite application of this pedal. I’d wager it would also sound great for acoustic guitar or clean electric guitar.

The E.W.S. Tri-Logic Bass Preamp II is not the kind of pedal everyone needs, but anyone looking for a musical, clean, and robust active EQ and boost should give it a spin.


E.W.S. Tri-Logic Bass Preamp II
Street $152
Pros Super clean; very musical EQ; excellent build quality
Cons Won’t work direct into a power amp

Controls VOLUME, GAIN (+20dB boost), BASS (±15dB @ 90Hz), MIDDLE (HI: ±10dB @ 800Hz, LOW: ±12dB @400Hz) TREBLE (±13dB @ 10kHz), PASSIVE/ACTIVE switch, HI/LOW midrange switch
Switch True bypass
Power 9–18 volts DC, or two 9 volt batteries
Input impedance Passive: 1 MΩ, active: 100 kΩ

Made in Japan
Warranty One year limited
Contact www.ews-us.com