Tenderfoot Electronics – TETRAD
Four-Oscillator Harmonic Digital Voice
TETRAD is a four-oscillator digital voice built to explore the harmonic and subharmonic relationships between frequencies. Starting from a single fundamental pitch, each oscillator can be offset along the harmonic series, the subharmonic series, or by fixed tuning offsets, unlocking everything from rich chords and shimmering arpeggios to dense microtonal clusters and animated super-saws.
With morphable waveshapes, user-editable chord banks, flexible envelope modes, and performance-oriented controls, TETRAD rewards both careful sound design and fearless experimentation. Built-in Wi-Fi editing allows you to customise and save harmonies directly from your browser, while hands-on front-panel editing keeps creative flow uninterrupted during live performance.
Key Features
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Four digital oscillators with harmonic, subharmonic, and detune offset modes
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16 waveshapes (morphable between sine, triangle, saw, and square)
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Harmony dial with 16 slots per bank × 16 banks (user-editable via Wi-Fi or on-panel)
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Chord save/delete functions with non-volatile memory storage
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Flexible envelope section with AR, ASR, and Cycling (LFO) modes
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Unison, Solo, and Round-Robin oscillator triggering modes
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Built-in low-pass filter with lock-mode pitch control
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Mixed single-output design for instant integration into your patch
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16-bit DAC output at 32kHz sample rate
Technical Specifications
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Width: 20 HP
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Depth: 20 mm
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Power Draw: +12 V: 162 mA; +5 V: 0 mA; -12 V: 18 mA
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Output Level: 10 Vpp mono
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CV Inputs: –3 V to +7 V
Manual
Availability
TETRAD is available now from our website and through our network of authorised dealers.
Panel colours may show subtle variations between manufacturing runs.
VideosFirmware:
Latest Firmware version: 1.9.5 - 5/4/2026
1.9.5 Improvements:
- Improved anti-aliasing of all wave tables (preset & user-generated)
- Added phase reset & envelope reset options in wi-fi menu
- Filter resonance setting remains after power cycle
- Added "Auto tuning" mode - frequency selectable via wi-fi menu
- Turn off the tuning lock (LED off), then hold the tuning lock button for 5 seconds until the light comes back on. Your Tetrad will be tuned to your set frequency at 0V.
- Simplified Wi-Fi Activation mode and improved Wi-Fi page interface & loading times
- After update - no need to adjust any dials - hold all 4 buttons for 5 seconds any time during runtime until the LEDs begin to blink rapidly - Wifi mode is now active!