The PG Korora Merlo review.
RatingsPros:Superb versatility yields a near-infinite variety of lush-sounding tremolos. Cons: Experienced some noise in use, and the rate knob would benefit from a more gradual taper. Street: $249 Korora Audio Merlo Harmonic Tremolo kororaaudio.com | Tones:  Ease of Use:  Build/Design: Value: |
The new Merlo harmonic tremolo pedal comes to us from Korora Audio, a small company in Seattle, Washington, that builds creative stomps like the Spira modulating filter (which won a Premier Gear Award in 2019). The Merlo isn’t inspired by brown-panel Fender or Magnatone tremolo, specifically. But it captures the spirit of the delicious tremolo on those amps while adding versatility, bountiful control, and textures spanning vintage classics and more radical modulations.
Like most harmonic tremolos, Merlo splits the guitar signal and uses LFOs to generate modulation. But in typical Korora style, that’s just the beginning. The EQ control is powerful, and the high- and low-pass filters modulate broader-than-usual frequency bands, emphasizing formant peaks that move with the modulation and create particularly rich, weird, and fine-tuned tremolo effects.
Shape Shifter
Two 3-way toggle switches are key to fine-tuning the Merlo’s voice. The upper toggle is a tone mode switch offering three settings: flat/transparent, mid peak, and warm, high-end roll off. Beneath that, an LFO selector switches between sine, triangle, and square waves. The LFO can be blended between wave shapes by using the, duh, shape knob. The EQ emphasis in a given wave peak can be enhanced with use of the color knob. It shifts the formant peaks, highlighting warmer or brighter tremolo tones and adding phase-like effects depending on the frequency shifts. It’s a powerful tool for shaping precise modulations, and can help achieve interesting blends of soft and hard-pulse textures. The rate and depth controls function as they do on a traditional tremolo, though, as we’ll see, the rate control is pretty range-y.
Dual status LEDs are a nifty visual touch. They pulse alternately in time with the split strands of the signal. If it gets a bit busy for your eyes, there are internal DIP switches to select whether you want the pulsing LEDs on or off. There’s also a DIP switch that determines whether the unit defaults to effect-on or -off on power-up.
Yet another, probably more useful, DIP switch activates a boost that can be set up to 3 dB in 1 dB increments. There are independent soft-relay footswitches for bypass and tap tempo. Input and output jacks are on the crown of the pedal, and Korora Audio recommends an external 9V DC power supply rated for at least 180 mA of current—which they thoughtfully supply in the box.
Pulse by Numbers
Needless to say, the Merlo can make a lot of sounds and bridges the gap between familiar vintage modulations and wilder fare beautifully. But, for me, the most appealing facet of the Merlo is the watery softness of the pulses you can achieve at many settings. Even in extra-choppy square and triangle wave modes, you can use the shape and color knobs to blunt the sharpest peaks while retaining the undulating feel of the more extreme wave shapes. That capability makes the unit feel more musical and flexible. The Merlo is also very responsive. Unlike some trems, it can be tuned to diminish pick attack less—even at extreme settings—and it feels incredibly dynamic at most settings.
The rate knob’s most conventional sounds live almost entirely within the first half of its rotation. Beyond that it tends to accelerate into hyper-speed warble. I’d guess that most players won’t use these speeds much, but the fast pulses are great for designing attention-grabbing passing phrases and solos. Personally, I’d prefer a pot with a more gradual taper and more precise control of traditional sounds. More experimental players might disagree. And, of course, the tap tempo is a very capable tool when you’re matching modulation rate to song tempo. At times, the extra color at many settings also seems to translate to a little extra noise from the pedal. (I used both the supplied adaptor and a Voodoo Lab Pedal Power ISO with isolated outputs.) Here again, though, the less noise-floor-obsessed may consider a little hiss fair trade for a wider range of sounds and EQ options.
The Verdict
The Merlo is a very hip effect and, in my humble opinion, a must-try for tremolo addicts. The harmonic tremolo sounds are complex and easy to tailor in precise ways (though the rate control might be an exception for some). The Merlo also gets a lot of great sounds out of a relatively simple control set. All that flexibility and modulation massaging potential will set you back a fair bit, at almost $250. But Merlo’s impressive performance often justifies the price.
Watch our demo:
A harmonic tremolo that features FM-generated LFO shapes, tap tempo, and three unique voicing modes.
Seattle, WA (June 22, 2020) -- Korora Audio introduces the Merlo harmonic tremolo pedal, featuring a wide palette of tone shaping options, LFO shapes, and tap-tempo rate control.
Like traditional harmonic tremolos, Merlo alternates between high-pass and low-pass signals. Merlo also allows setting the crossover frequency, as well as the resonance and roll-off of the high and low pass filters. It also uses a more complex filter design that adds subtle (and sometimes pronounced) formants to the sound.
Merlo uses frequency modulation (FM) in the LFO to produce a wider range of musically interesting envelope shapes. These include sine, triangle, and pulse envelopes, and also include ramps and other asymmetrical shapes. The Shape control allows continuous morphing from one shape to a completely different one, for example from a sine to a ramp.
Not limited to being a vintage circuit emulation, Merlo provides a range of textures that will boost your creativity in any tremolo situation, or may have you using a tremolo where you never would have before.
Features:
- Three unique tone shaping modes offering a wide palette of tremolo voicings
- FM generated LFO shapes
- Tap tempo that glides to the new rate
- Soft touch true bypass
- Top mounted jacks
- Standard 9V DC power (180 mA), power supply included
Merlo is available now, priced at $249 direct from kororaaudio.com, reverb.com, and select retailers.
Watch the company's video demo:
For more information:
Korora Audio
The 60+ guitars, amps, pedals, basses, and accessories that stood out from the crowd and earned our coveted Premier Gear Award this year.
Carr Telstar
This handwired 17-watt, 1x12 combo employs two familiar power tubes—a 6L6 and an EL84—to produce the presence and immediacy of a great Fender tweed, the thrilling sparkle of Vox overdrive, and a tighter, tougher bass response than you’d expect from a strictly vintage midsized combo. Telstar’s suave spring reverb, strong note fundamentals, articulate attack, and extraordinary touch response caused Joe Gore to exclaim, “I love this frickin’ amp.”Read the review
$2,450 street, carramps.com
Watch the First Look:
Plus! December Premier Gear Award Winners!
Read the full reviews on the pages indicated below!
1. Peavey Invective.MH — $699 street, peavey.com
2. Chase Bliss Dark World — $349 street, chaseblissaudio.com
3. Comins CGS-16 — $2,399 street, cominsguitars.com
4. Ernie Ball Music Man Short-Scale StingRay — $1,999 street, music-man.com
5. EBS MicroBass 3 — $349 street, ebssweden.com