The Source Audio Programmable EQ is a compact, DSP-driven digital equalizer pedal released by Source Audio in 20111. It gives the player hands-free access to four user-programmed EQ settings, a +/-18dB range over seven frequency bands, and up to 12dB of clean boost, all in a cast aluminum housing about the size of an MXR Phase 9023. Premier Guitar described it as "a 56-bit, DSP-driven, MIDI-capable digital equalizer pedal that enables you to save up to four footswitch-selectable settings and an output control that works as a clean boost"4.
It was designed for both bass and guitar, with an Octave Extend function that adds a band at 62Hz to accommodate bass frequencies2. Over time it became one of Source Audio's most successful products5, landing on the boards of pro guitarists including David Gilmour, Steven Wilson and John Mayer6. In 2020 it was succeeded by the Source Audio EQ2 Programmable EQ1.
What it is and what it does
The Programmable EQ is an EQ pedal built around what No Treble called "a proprietary 56-bit Digital Signal Processor, the SA601 and crystal-clear 24-bit converters"4. Performer Mag noted at the time that "EQ pedals are nothing new to guitar or bass players, but Source Audio's new pedal allows for storable presets, while still maintaining a simple interface in a small package"3.
In use it works like a programmable graphic EQ: you dial in a curve, save it to one of four preset slots, and recall it from the footswitch. The output control doubles as a clean boost of up to 12dB, and Premier Guitar noted that the knob "glows brighter the more you crank it up"4. Performer Mag found that "dialing in various EQ settings gives the desired effect, from a deep 'V' midrange scoop, to boosting specific frequencies to add more 'presence' in a live setting"3.
Beyond straight equalization, the pedal has two unusual functions:
- Octave Extension (OE): a parameter well-suited for bass that manipulates an extra frequency of 62Hz, one octave below 125Hz, and remains accessible after exiting Backpage mode4.
- Auto-Scroll (AE): continually scrolls through all saved settings, which can produce sounds like a tremolo-meets-sequencer-meets-ring modulator depending on how extreme the presets are. Its speed is set by the Switching Speed (SW) parameter, and faster settings give more extreme results4.
The controls
| Control | What it does |
|---|---|
| Band-select buttons (pair) | Scroll to the desired frequency; pressing both simultaneously zeroes all bands4 |
| Encoder knob (large, center) | Adjusts the amount of boost or cut on the selected band43 |
| LED display | Shows the EQ bands, with lights indicating the levels43 |
| Output knob | Sets clean boost up to 12dB, backlit by a blue LED3 |
| Save button | Stores a preset EQ3 |
| Select button | Toggles through the four presets3 |
| Footswitch | True bypass on/off; holding it down scrolls through the presets3 |
The interface keeps deep editing out of the way: Performer Mag highlighted that the left and right cursors "allow the user to scroll back and forth through the bandwidths easily"3.
Power, MIDI and connections
The pedal runs on a 9V battery, included in the box, or an external power supply, which is not included3. It has a MIDI input for recalling presets or engaging and bypassing the effect remotely from a MIDI controller3. The hardwire true bypass "utilizes a small-signal relay for improved reliability and remote switching capabilities"2.
Unlike its successor, the original Programmable EQ runs on a battery. The EQ2 moved to a 9V DC adaptor only, drawing 180mA7.
History: from the Programmable EQ to the EQ2
Source Audio released the Programmable EQ in 2011, adding it to their line of bass pedals as "a compact, cast aluminum stompbox offering hands-free access to four unique and user-programmed EQ settings"12. It gradually became one of the company's most successful products5, a "tremendously popular pedal that landed on the boards of numerous pro guitarists"6. Pete Thorn, reviewing the EQ2 on his YouTube channel in 2020, recalled:
"i first noticed this pedal actually on gilmore's pedal board it was actually the first version of the source audio programmable eq on david's board"
The EQ2 Programmable Equalizer, the second generation of Source Audio's equalizer pedal, was presented at NAMM 2020 and released on May 22, 2020 at a $269 street price95110. It expands the concept to 10 fully adjustable bands, stereo inputs and outputs, up to 128 presets, full MIDI compatibility with five-pin MIDI DIN input and thru jacks, an onboard noise gate, dynamic limiter and chromatic tuner571.
What reviewers said
Premier Guitar's reviewer praised the pedal's transparency: "I was struck by the Programmable EQ's transparency, which means you can finetune the sound of your rig to a room or a musical environment without sacrificing any character"4. The review summed up its strengths as "excellent and easy to use tone-sculpting options"4.
Performer Mag's Chris Devine found that "sound-wise it's great (no added noise or hiss when engaged), but like on any EQ, maxing out settings can bring some hiss into the mix, depending on the frequencies"3.
Later coverage of the EQ2 has looked back on the original as the pedal that made the line what it is. Guitar World's Trevor Curwen, reviewing the EQ2, noted that its predecessor's four-preset, MIDI-controllable format was what "landed on the boards of numerous pro guitarists"1, and gearnews.com's 2025 EQ pedal guide described the EQ2 as "far more than a graphic EQ" with 128 presets, full MIDI control and an expression input for sweeping between settings11.
Players who used it
The original Programmable EQ is documented on the boards of David Gilmour, Steven Wilson and John Mayer6. Pete Thorn noted that Gilmour ran the first version of the pedal on his board alongside a number of fuzz and overdrive pedals8.
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Questions
Is the Source Audio EQ2 analog or digital?
Digital. The EQ2 leans on its digital architecture to perform a wide range of EQ tasks, and it connects to Source Audio's Neuro Desktop Editor over USB for advanced editing and firmware updates. The original Programmable EQ was likewise a DSP-driven digital pedal, built around a proprietary 56-bit processor with 24-bit converters.
Is the EQ2 true bypass or buffered?
Both, selectable. Source Audio calls it Universal Bypass: you choose between high-quality signal relays for true bypass and transparent buffers for analog bypass. The original Programmable EQ used a hardwire true bypass design with a small-signal relay for reliability and remote switching.
How many presets does the Source Audio EQ2 hold?
Up to 128. The maker lists 4 onboard presets, 8 in Preset Extension Mode, or 128 by turning the encoder while holding the Preset Select button. Presets can also be recalled with MIDI PC messages. The original Programmable EQ held four footswitch-selectable presets.
Does the Source Audio EQ2 have a tuner?
Yes. The EQ2 includes an onboard chromatic tuner, which Source Audio describes as adding to the pedal's flexibility and feature set. The tuner can also be reached from an expression or tap switch connected to the control input.
Can the EQ2 run different EQ settings on left and right outputs?
Yes. In Split Mode the EQ2 can split the signal and simultaneously run two discrete EQ presets, one for each stereo output, with routing options including mono to stereo and stereo to stereo. Each channel also has an independent output gain control.
How much boost and cut does each band of the EQ2 give?
Each of the EQ2's 10 bands offers up to +/-18dB of boost or cut, and each band can be placed anywhere from 20Hz to 20kHz with an adjustable Q, up to 10 times narrower. A master volume adds up to 12dB of clean boost on top.
Sources (11)
- Source Audio Announces the EQ2 Programmable Equalizer, Premier Guitar, 2020-05-22
- Source Audio Releases Compact Programmable EQ Pedal, No Treble, 2011-10-05
- GEAR REVIEW: Source Audio Programmable EQ Pedal, Performer Mag, 2012-01-17
- Source Audio Programmable EQ Pedal Review, Premier Guitar, 2012-04-06
- Source Audio EQ2 Programable Equalizer, Delicious Audio, 2025-05-09
- Source Audio EQ2 Programmable Equalizer, Pedal of the Day, 2023-09-07
- Source Audio EQ2 Programmable EQ review, MusicRadar, 2022-03-06
- THE TONE SWISS ARMY KNIFE! Source Audio EQ2 Programmable Dual EQ, youtube.com, 2020-07-28
- Source Audio Unveils the EQ2 Programmable Equalizer Pedal, No Treble, 2020-03-08
- EQ2 Programmable Equalizer: Source Audio releases The Ultimate Tone Sculpting Machine, MusicPlayers.com, 2020-05-20
- The 7 Best EQ Pedals for Every Budget: Shape Your Tone in Seconds!, gearnews.com, 2025-09-15
Pete Thorn