PHENOL - Patchable Analog Synthesizer

Portable, patchable, powerful modular-inspired synthesizer.

Price and Availability | Accessories | PHENOL Manual | Sounds | Videos | PHENOL FAQ

The PHENOL Kickstarter was a success! Thank you to all backers who supported the project!

PHENOL is a new type of electronic instrument from Kilpatrick Audio. Inspired by modular synthesizers, PHENOL offers the creative potential, sound and hands-on experience of a modular synth, in a sleek, compact and affordable package. And best of all, PHENOL is compatible with modular systems because it uses the same voltages and banana connectors as the Kilpatrick Format and similar modular synthesizers.

Whether you already love modular synthesizers and want a smaller instrument for portability, or whether you've heard about modular synths and want to get your feet wet, PHENOL offers an amazing instrument at a great price.

Features and Specs

  • Banana patch system with colour-coded jacks and voltages compatible with Kilpatrick Format and other modular systems - PHENOL Panel Layout
  • Two analog VCOs - triangle, ramp and pulse outputs
  • Two analog filters - low pass and band pass (formerly labeled high pass)
  • Two analog VCAs with level control
  • Two envelope generator / LFO combos with many unique features (digital)
  • An LFO with sine and random output (digital)
  • Internal MIDI to CV converter with DIN and USB MIDI interfaces
  • Built-in MIDI sequencer / looper
  • Compact mixer with digital delay (330ms of delay time)
  • Digital pulse divider - divide MIDI clock, LFOs or audio signals into useful musical divisions
  • Buffered analog mixer / mult / inverter with level control
  • Two external audio inputs buffer and amplify line-level signals - process drum machine or other audio sources through the system
  • Rear panel connections / controls:
    • USB-B port for USB MIDI connection to a PC / Mac
    • Headphone and line outputs (1/4" jacks)
    • Power button
    • DC power input - 2.1mm coax - centre positive 24VDC
    • Ground banana jack
    • External input (1/4" jacks)
  • Power input: 24VDC @ 250mA (500mA regulated supply required)
  • Operating temperature: 15C to 30C (59F to 86F)
  • Storage temperature: -10C to 45C (14F to 113F)
  • Dimensions: 15.8"W x 8.8"L x 2.5"H (including feet and knobs)
  • Weight: 5lbs (2.27kg)
  • Universal input power supply (100-240V) included with plugs for most countries
  • Designed and made in Canada using high quality parts
  • Warranty: 1 year (30 day warranty on cables)
  • Comes packaged with 10x banana cables.

Price and Availability


PHENOL on Grass




Enjoy using your PHENOL anywhere with the PHENOLgo! USB to 24V power supply for PHENOL!


  • Converts 5V USB power to 24V required by PHENOL
  • Works with USB power banks, solar panels, etc.
  • Over-current protected and >90% efficient
  • Includes integrated 8" USB cable and 6' 24V cable with 2.1mm plug

Price: $69 USD

Buy Now

Banana Cables

Banana Cables - 10 pack

Each 10-pack includes:

  • 2x black 12" cables
  • 2x red 12" cables
  • 3x green 18" cables
  • 3x yellow 18" cables

Price: $55 USD

Buy Now

Banana Mini Pink Banana Mini Red/White Banana Mini Red/White/Blue

Banana to Minijack Adapter Kit

This kit allows you to connect PHENOL or another banana jack synth to Eurorack or other synths that use 3.5mm minijacks. Available in three colour combinations!

Each kit includes:

  • 5x banana (M) to minijack (F) signal adapters (150mm / 6")
  • 1x banana (M) to minijack (F) ground adapter (150mm / 6")

Price: $39 USD

Buy Now

International PSU

International Power Supply

If you have a Kickstarter Edition or a PHENOL purchased from a US dealer, your PHENOL came supplied with a 100-240V input power supply with a US-style plug. We now offer a high quality power supply that comes with US, UK, EU and Australian plugs. Avoid having to use a plug-changing adapter.

Price: $25 USD

Buy Now


All PHENOL documentation is available online. Click here for the full PHENOL manual with links to demonstration videos.


The Stereo Effect Project - Gate In
All sounds except the drums are made with PHENOL. Thanks to Keith Murray for putting PHENOL through its paces and making this excellent track!

PHENOL Prototype - Jam 1
A very early recording of the prototype PHENOL unit in the studio!

PHENOL Prototype - Jam 2
(Random Transfer at the controls)


PHENOL Modular Synth

Spotlight: Tom Third

Spotlight: Kat Burns

Spotlight: Carl Didur and Andrew Dordevic

The Stereo Effect Project - Gate In

Circuits - PHENOL Demo

Mini Sequencer Demo

Banana to Minijack Cables

Experimental Demo

More Experiments


What about S&H and Stepped LFO Outputs?

Although PHENOL doesn't have a dedicated sample and hold circuit, you can create some of the same effects with the LFO Random output. If you want those stepped random filter cutoff sounds, or just some crazy pitches that go all over the place... this is already possible.

Another common use of a sample and hold is to make stepped voltages from LFOs. Don't worry, because we have you covered here too. Both envelope sections have a Steps mode where you can quantize the output. You can go from 2 steps (lowest voltage / highest voltage) all the way up to a perfectly smooth linear ramp. There are 16 distinct settings.

How do the Envelopes work? They look like they have a lot of modes.

The envelopes are some of the most powerful features of PHENOL. They have three dedicated control buttons which select from three modes each as follows:

Envelope Type

This setting affects the overall behaviour of the envelope.

  • Attack / Hold / Release - Envelope mode mostly for regular note amplitudes. The envelope will ramp up to the maximum level, hold as long as the gate is applied, and then fall back to the minimum value when the gate is release. The up and down times can be controlled separately.
  • Attack / Release - For percussive sounds or snappy bass sounds, when triggered the envelope will ramp up to the maximum value and then immediately start ramping back down to the minimum value. Holding the gate has no effect.
  • Oscillator Mode - This mode works as a low frequency oscillator. The first control affects the speed, and the second control affects the amplitude. When the mode is switched on the gate is latched so that it runs all the time. If you apply a gate you can operate the oscillator in a momentary mode.

Modulation Control

This setting affects the function of the third control pot.

  • Steps - The third control affects the smoothness of the envelope or oscillator shape. The control can be set from 2 levels (lowest / highest) all the way up to the smoothest value. Various useful divisions can be made.
  • Arp - The third control affects which arpeggio is applied to the output. Instead of equally-spaced intervals like in steps mode, a number of different musical arpeggios are selectable.
  • Gate Delay - The third control affects the delay of the gate when turning on. This allows effects such as a filter envelope or modulation to start after a delay.

Output Control

This setting affects the output signal.

  • Normal - The output ramps from the lowest to the highest value.
  • Invert - The output is inverted and ramps from the highest value to the lowest value.
  • Absolute - The output ramps from the centre point and goes positive only. The range is reduced to half.

More Tech Details

PHENOL is based on the Kilpatrick Format modular synth released by Andrew Kilpatrick in 2012. Specs for this system designed for DIY and commercial makers to use are freely available: Kilpatrick Format Technical Specifications

The use of banana jacks makes it really easy to interface PHENOL with other gear, even your own projects. The jacks are inexpensive and easy to build into nice looking weekend DIY projects. If enough people are interested we'll dedicate a section of our site to feature interesting things you can build to add on to your PHENOL!

  • Gate / Pulse Signals - A gate or pulse signal is 0V when off and 5V when on. These are output on red banana jacks and input on white jacks. Input trigger when the voltage rises above about 1V.
  • Audio / CV Signals - Audio and CV signals range from about -5V to +5V. These signals are output on grey banana jacks and input on black jacks. Envelopes and VCAs use the full range of control from -5V to +5V. All signals are intercompatible.
  • Pitch CV Signals - Pitch signals calibrated to musical pitch are specified as 1V/octave. When disconnected (0V) oscillators should be in the centre of their range.
  • Impedances - As a general rule: CV outputs are 1K impedance (100 ohms for pitch CV) and 20K or more input. (100K for pitch CV)


We publish some mods you can make to your PHENOL if you have some technical skills.

Voltage Compatibility with Other Systems

Many people have asked about the compatibility between PHENOL and other modular formats. As was stated above, PHENOL uses the same voltage standards as the Kilpatrick Format modular system which will hopefully be adapted as an industry format within the coming years. It solves a number of existing problems with most modular systems both electrically and mechanically.

Specific compatibility notes:

  • All CV and audio signals range from -5V to +5V. Pitch uses the industry standard 1V/octave.
  • Pulse and gate signals use 0V = off, and +5V = on. This is pretty much the standard on most systems. PHENOL pulse/gate inputs will activate with voltages above about 1V.
  • The main difference with Kilpatrick Format / PHENOL is that envelopes and VCAs use the entire voltage range, instead of simply positive-only voltages which are often used on other systems for envelopes, VCAs and some digital modules like MIDI to CV converters. You might need to boost an external signal (with the ADDER section) or attenuate a signal leaving PHENOL (with the input control on the other module) to make them interface perfectly.
  • The use of fully bipolar voltages for all CV signals means that every output and input is compatible and you never have to wonder if the range of signal will be right. Additionally, always using bipolar voltages means that the local control such as tuning, cutoff, etc. is generally at the middle of its range and the CV input simple adds or subtracts to the existing setting. This makes logical sense and works better when patching and unpatching on the fly.
  • Conversion to/from other cable types such as minijack (1/8" or 3.5mm) or 1/4" can be easily accomplished by making a small razorout box or just making cables that have a banana plug on one end and the other type of plug on the other end. The only important concern is that you must connect the ground of your other system to the front panel ground connection on PHENOL before patching. You can use a minijack / banana cable plugged into an unused jack on your other system to ensure the ground is connected all the time. PHENOL provides a dedicated ground jack for this purpose.


We often get many of the same questions from people, so here are some of the most common questions and answers.

How can PHENOL be connected to other synths?

PHENOL uses voltages which are compatible with most synths including Eurorack as well as stand-alone synths. For synths which use banana cables such as Buchla, Serge, Fenix, etc. you can simply use the included patch cables. For Eurorack and synths which use minijacks, we make convenient adapter cable kits which are available through dealers or through our online store.

Tell me about grounding PHENOL with other devices

Because PHENOL uses banana patch cables, if you are going to patch the CV or audio signals from the top panel to other gear, there needs to be a common ground between them. This can be accomplished in a few different ways:

  • In our banana to minijack cable kits, an extra audio cable is supplied, Connect it to any of the rear panel audio connectors (we recommend one of the EXT IN jacks) and plug it into an unused port on your other synth.
  • If both synths are connected to the same audio mixer or sound card, the ground is probably already connected. In most cases this will be enough.
  • If you run audio through another synth or vice versa using the audio connections, the ground is already connected.

There is no need to worry about ground when dealing with the rear panel 1/4" audio jacks, USB or MIDI connections.

Can I process audio signals with PHENOL?

Yes, PHENOL has two external audio inputs that can be used to bring in audio from line level sources such as mixers, drum machines, other synths, etc. Simply patch in a 1/4" cable and the signal will appear on the top panel in one of the oscillator sections. You can patch it just like any other signal in the system. There is no need to ground your audio source to PHENOL other than using the audio cable.

The sound is gritty / noisy, how can I make it cleaner?

Just like with audio mixers, in a modular synth there are many places where the audio signal can be amplified and attenuated. It's important to keep a hot signal throughout as much of the signal path as possible. One common mistake that people make is by running the VCA too low. When you are controlling the VCA with an envelope signal or LFO, the proper setting for the AMP control is at about 12 o'clock. The general rule of thumb is that the input LEDs on the mixer should be blinking periodically or steadily on. If you never see them, check your settings throughout the patch.

When using PHENOL with headphones, the MASTER level setting will be determined by the type of headphones. However in a setup with a mixer, you should run the MASTER control so that the master LEDs are blinking as well. If the signal is too hot for your mixer, adjust the input gain / trim knob to accommodate the hotter signal. Running the hottest signal throughout the entire signal path will result in the best sound, regardless of whether the equipment is analog or digital.