The Carl Martin Ottawa is an analog auto-wah pedal with an optical envelope filter. Instead of being controlled by a foot treadle, the wah effect responds to picking dynamics: soft playing can produce a dark and subdued sound, while a stronger attack opens the filter for a more pronounced, dynamic wah effect. The pedal can be used with both guitar and bass.

Ottawa is suited to guitarists who want wah-like movement without a traditional wah pedal. It can be used for funk-inspired rhythm guitar, expressive solos and experimental filter effects. The Low Pass setting is particularly well suited to bass.

Adjust the wah response to your playing

The Attack control sets the filter's sensitivity to the input attack. A higher setting activates the effect even with light playing, while a lower setting requires a more pronounced attack. This allows the response to be adjusted to both the instrument and playing style.

Q controls the filter's resonance and bandwidth. A wide setting gives a warmer, rounder wah character, while a narrow setting produces a sharper, more focused effect. Tone acts as a high-cut filter that can reduce the high frequencies, while Level lets you match or increase the signal level relative to the bypass signal.

Three filter modes

The Select switch chooses between High Pass, Band Pass and Low Pass. The three modes change the filter's focus and provide different tonal options, from deep and throaty wah sounds to sharper, disco-inspired textures. Attack, Tone and Q can be combined to fine-tune the response.

How the envelope filter works

An envelope filter responds to the strength of the input signal. On the Ottawa, filter movement follows the dynamics of your attack, allowing the wah-wah effect to be created directly with your hands. This is especially useful when rhythm and picking nuances are an active part of the sound.

True bypass and connections

The Ottawa features true bypass, routing the signal around the effect when the pedal is disengaged. It has one 6.35 mm jack input and one 6.35 mm jack output.

Technical specifications

• Effect type: Analog optical envelope filter / auto-wah
• Bypass: True bypass
• Filter modes: High Pass, Band Pass and Low Pass
• Controls: Attack, Tone, Q and Level
• Input impedance: 1 MO
• Output impedance: 330 O
• Signal-to-noise ratio: 56 dB
• Input: 1 x 6.35 mm jack
• Output: 1 x 6.35 mm jack
• Power supply: 9 V DC, regulated, minimum 30 mA, 2.1 mm centre-negative
• Current draw: Max. 14 mA
• Battery operation: Not supported
• Dimensions: 60 x 115 x 50 mm (W x D x H)
• Weight: 340 g

The Carl Martin Ottawa delivers a wah-like effect that follows your attack, allowing the sound to be shaped from warm, broad sweeps to focused funk tones.