Korora Audio Launches the Merlo Harmonic Tremolo

June 22, 2020 · 3 sources

Korora Audio announced the Merlo, a harmonic tremolo pedal, and said it was available immediately, priced at $249 direct from kororaaudio.com, reverb.com, and select retailers¹. The pedal had first been shown a year earlier: Korora Audio launched it at the Summer show in June 2019 as the company's second effect².

Like traditional harmonic tremolos, Merlo alternates between high-pass and low-pass signals, splitting the guitar's spectrum and sweeping each side against the other rather than simply raising and lowering the overall volume. Beyond that basic behavior, the pedal allows setting the crossover frequency, as well as the resonance and roll-off of the high and low pass filters, giving the player control over how the two bands are voiced¹.

The heart of the pedal is its low frequency oscillator, the circuit that drives the rate and shape of the signal change. Korora Audio says Merlo uses frequency modulation (FM) in the LFO to produce a wider range of musically interesting envelope shapes than a conventional design³. The available shapes include:

• Sine, triangle, and pulse envelopes
• Ramps and other asymmetrical shapes¹

A Shape control allows continuous morphing from one shape to a completely different one, for example from a sine to a ramp¹. On the company's own page for the pedal, the maker described how the shapes interact with the rest of the controls:

Other announced features included tap tempo that glides to the new rate rather than jumping to it, and a soft touch true bypass switch¹. The pedal runs on standard 9V DC power at 180 mA, with the power supply included¹.

In the launch announcement, Korora Audio described the pedal's aim in broad terms, saying it "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"¹.