Source Audio C4 Synth

Source Audio C4 Synth


Out of stock

The C4 Synt

The C4 Synth unites all the sound creation tools of a classic Eurorack modular synthesizer and packages them in a compact and easy-to-use effects pedal for guitar or bass. Out of the box the C4 offers six dynamic synth tones that range from vintage analog to the thoroughly modern. It is essentially a modular synth in a small pedal with unprecedented tracking abilities, lightning-fast response, and countless sound options. With the addition of the Neuro Desktop Editor (a free download for Mac and Windows machines) and Mobile App. (for iPhone and Android) it’s easy to browse from the ever-growing library of highly-inspired presets created by the Source Audio crew and the expanding community of C4 enthusiasts.

​It’s that easy. When you’re ready to explore beyond the C4’s six onboard presets simply jump to the Neuro Desktop’s Cloud tab or the Neuro Mobile App’s Browse function and check out all the available presets created by the Neuro Community and the Source Audio team. We’ve got a huge and growing-huger collection of vintage and contemporary synth effects that are guaranteed to amaze. When you find that mind-blowing tone that you can’t live without, simply click the BURN icon and upload the preset directly to your C4 – it will be waiting for you at the next gig.

On the surface, the C4 features a simple 4-knob interface and a choice of six amazing guitar/bass synthesizer effects – just plug-in and play. If you want to take things to take things a bit further, we urge that you connect the C4 to our Neuro Preset Editing & Browsing tools. The Neuro Mobile App is available for free at the App Store (iOS) and Google Play (Android). The Neuro Desktop Editor is available as a free download for Mac or Windows systems on our Downloads page. Inside Neuro you will find the tools to personally create your own synth utopia. Use the C4’s collection of four parallel voices, three oscillator wave shapes, ten-plus envelope followers, twenty-plus modulating filters, distortion, tremolo, pitch shifting, intelligent harmonization, FM synthesis, two programmable sequencers and more to dial in that perfect tone.



INPUT (the Primary(Default) Parameter): Adjusts the volume level of the input signal. Given the reactive nature of the C4’s pitch detectors and envelope followers and the varying output levels of different instruments and their passive or active pickups, it is important to set the level of the signal going to the processor. The C4 also includes a simple process for calibrating your instrument to the INPUT level (go to the INPUT/SENSE Knob section for calibration instructions)in the manual. • SENSITIVITY (the Alternate Parameter):Adjusts how reactive the envelope filter is to the incoming signal. If you like to play hard, but still want a smoother, more relaxed envelope filter, you should turn down the SENSITIVITY. For a sharper response to lighter playing, turn up the SENSITIVITY.
MIX (the Primary (Default) Parameter): Adjusts the balance between the natural dry tone of the instrument and affected wet signal. A 50/50 mix of wet dry signal resides at roughly 12 o’clock on the knob. VOLUME (the Alternate Parameter) Adjusts the master VOLUME/Output of the pedal. Keep in mind that the overall VOLUME will likely vary depending on the signal density of the preset.
The functions of these knobs vary depending on the selected synth engine.
Effect Selector Toggle Switch
Use the C4’s three-position toggle switch and two preset banks to easily access six different presets. First Preset Bank (Indicated by the green center LED): default the center toggle switch selects between three presets stored in the first bank of presets. Second Preset Bank (Indicated by the red center LED): Pressing the ALT button on the topside of the pedal opens access to the second bank of presets . After pressing the ALT button the small LED at the top of the pedal’s face will start to blink, indicating that the second preset bank is accessible with the toggle switch. Upon moving the toggle switch the center LED will turn red indicating the current preset is drawn from the second bank
Enables or bypasses the effect. Also, pressing and holding the footswitch from the bypassed state toggles between the first and second preset banks.
ALT (Alternate Function)Button
The smallblack button located on the topside of the pedal next to the CONTROL INPUT jack. Pressing the ALT button temporarily puts the pedal into Alternate Control Mode (indicated by the blinking top center LED). Alternate Control Mode switches from the Primary to Secondary function of the INPUT/SENS and MIX/VOL knobs. Also moving the center toggle switch will switch between the Green and Red Preset Banks (go to the Preset Banks section for more info)in the manual.

Toggle switches

Hold to access Alt Functions
Alt Functions are only accessible when this button is held
Press to Select Synth mode
(Press to Select Synth Mode) Poly: Multi-Voice Synthesizer with polyphonic chord tracking Mono: Single Voice Dual Osc Synth w/monophonic tracking Arp: Turns your chords into sequenced patterns linked to the tap tempo Dry: Disables the Synth. Allows the filter, delay and pitch shift to be applied to the input signal


Tap Switch
Sets the time for the delay line and arpeggiated Synth Alt Function: Envelope Type Changes the Filter Envelope from Triggered Envelope to Envelope Follower Hold Tap: Momentarily turns Delay Feedback to max
Disables processing and passes the input through to the output Alt Function: Synth Waveshape Changes the Synth waveshape from Sawtooth to Square


Premium analog signal path and 24-bit AD/DA w/32 bit floating point DSP
Selectable True Bypass (Relay) or Analog Buffered Bypass


10.8cm x 11.4cm x 5cm
0.41 kg


9V DC center-negative, 150mA, 2.1mm jack
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