Eurorack Reference / modules /endorphin-es/grand-terminal audit site v0.1 — milestone 3
endorphin-es/grand-terminal

Grand Terminal

Endorphin.es

Dual multi-mode filter (8 types per channel), dual looping/AD/ASR envelope generator, and stereo 16-effect FX processor (Cabin Pressure). Operates as a complete synthesizer voice when paired with an oscillator.481

Capabilities 15

Bandpass Filterbandpass-filter
481
Comb Filtercomb-filter
481
Delaydelay
Stereo FX processor includes Ping-Pong Delay and Tape Echo Delay effects among 16 total effects.481
Diode Ladderdiode-ladder
481
Envelope Generatorenvelope-generator
Dual independent looping/AD/ASR envelope generators (called 'Airplanes') with bipolar and unipolar outputs; can function as LFOs in loop mode.481
Highpass Filterhighpass-filter
481
Lowpass Filterlowpass-filter
481
Lowpass Gatelowpass-gate
Two of the eight filter modes (Vactrol LPG and Resonant Vactrol LPG) implement Buchla-style low-pass gate behavior with vactrol emulation.481
Multimode Filtermultimode-filter
Eight selectable digital filter types per each of two filter channels (A and B), selectable via MODE button presses.481
Reverbreverb
Stereo FX processor includes Hall, Shimmer, Room, Plate, Spring, Gated, and Reversed reverb types among 16 total effects.481
Stereo Processorstereo-processor
Stereo 'Cabin Pressure' FX section with 16 effects in two banks (Airways and Darkwaves); separate stereo line output and mono modular output.481
Synth Voice Coresynth-voice
Functions as a complete modular synthesizer voice when combined with an oscillator, providing dual envelopes, dual filters, and stereo FX.481
Transistor Laddertransistor-ladder
481
Vactrol-basedvactrol
Vactrol LPG and Resonant Vactrol LPG modes emulate opto-coupler (vactrol) behavior in a Sallen-Key filter topology.481
Vcfvcf
481

Jacks 18 — 10 in / 8 out

NameSignalVoltageDescription
Inputs (10)
Airplane A Check-Ingate—481
Airplane B Check-Ingate—481
Cabin Fever CVcv—481
Cabin Pressure CVcv-5V to 5VBipolar CV input for the FX dry/wet (Cabin Pressure) parameter. Cabin Pressure knob acts as attenuator when CV is present. Also becomes effect-select CV in Cabin Pressure Scan mode (-5V to +5V, 8 zones).481
Gate A Inaudio—AC-coupled audio input for filter channel A. Accepts modular level (+/-5V) at full CCW trim, or line level (~1Vpp) at full CW trim. Stereo jack; ring passes right channel to filter B when stereo cable used.481
Gate B Inaudio—481
X CV Acv0V to 5VUnipolar CV input for filter A's X parameter (typically cutoff frequency). Knob acts as attenuator when CV is present.481
X CV Bcv0V to 5V481
Y CV Acv0V to 5V481
Y CV Bcv0V to 5V481
Outputs (8)
Airplane A Bipolar Outcv-5V to 5V481
Airplane A End-of-Stage Outtrigger0V to 6V481
Airplane A Unipolar Outcv0V to 8V481
Airplane B Bipolar Outcv-5V to 5V481
Airplane B End-of-Stage Outtrigger—481
Airplane B Unipolar Outcv0V to 8V481
Mono Outaudio-5V to 5VModular-level mono output (~+/-5V) where left and right channels are summed together.481
Stereo Outaudio—True stereo line output. Approx. 1Vpp (0dBu) at normal volume, up to 3Vpp (+4dBu) at maximum. Can drive headphones directly. Left and right channels mixed for mono output.481

Parameters 19

NameTypeRangeBehavior
A Trimknob—Input gain trim for filter channel A. Full CCW = modular level (+/-5V). Full CW = ~10x gain for line-level sources (~1Vpp). Signals exceeding ~+/-6.9V are soft-clipped.481
B Trimknob—Input gain trim for filter channel B. Full CCW = modular level (+/-5V). Full CW = ~10x gain for line-level sources. Signals exceeding ~+/-6.9V are soft-clipped.481
Cabin Feverknob—Primary and secondary effect parameter knob. Assignment depends on the effect selected. Short press TAP for >1 second switches to secondary mode (controls a different parameter per effect). Each effect's memory stores the knob value.481
Cabin Pressureknob0% – 100%Controls the dry/wet mix for the FX processor. Full CCW = dry only; full CW = 100% wet. In Cabin Pressure Scan mode, becomes a manual dry/wet control only. Corresponding CV jack accepts bipolar -5V...+5V with knob acting as attenuator.481
Final Volumeknob—Controls the volume of both the stereo line output and the mono modular output. Blue knob at top center of module.481
Landing (Decay/Release) Aknob1ms – 10000msControls the decay/release (landing) duration of envelope A from 1ms to 10 seconds. When no CV patched, knob sets curve shape (CCW=exp, center=linear, CW=log). With CV, acts as attenuverter.481
Landing (Decay/Release) Bknob1ms – 10000ms481
MODE A (Follow Me)button—Short press cycles through 8 filter types for channel A. Hold >1 second accesses secondary functions (panning and volume) for channel A.481
MODE B (Follow Me)button—Short press cycles through 8 filter types for channel B. Hold >1 second accesses secondary functions (panning and volume) for channel B.481
TAPbutton—Tap tempo input for delay effects; spring pluck trigger for Spring Reverb; hold >1 second to toggle Cabin Fever secondary mode; hold 5 seconds to switch FX bypass channel.481
TYPE (Cabin Pressure)button—Short press cycles through 16 effect types (two banks of 8). Long press (>1 second) toggles FX bypass for the selected channel (Gate A by default; holding TAP for 5 seconds switches bypass to Gate B).481
Take Off (Attack) Aknob1ms – 10000msControls the attack (take-off) duration of envelope A from 1ms to 10 seconds. When no CV is patched, knob sets curve shape: full CCW = exponential, center = linear, full CW = logarithmic. When CV is patched, knob acts as attenuverter.481
Take Off (Attack) Bknob1ms – 10000ms481
Trip Selector Aswitch—Three-position switch selecting envelope A mode: far right = Cruise (AR/ASR), middle = Transient (AD), far left = Loop (LFO).481
Trip Selector Bswitch—Three-position switch selecting envelope B mode: far right = Cruise (AR/ASR), middle = Transient (AD), far left = Loop (LFO).481
X Aknob—Controls filter A's X parameter (typically cutoff frequency). Acts as CV attenuator when CV is plugged into the X CV jack. In secondary mode (held MODE button), controls panning.481
X Bknob—Controls filter B's X parameter (typically cutoff frequency). Acts as CV attenuator when CV is plugged into the X CV B jack.481
Y Aknob—Controls filter A's Y parameter (typically resonance). Alternative assignments: vactrol decay time (#3), bandwidth (#7). In secondary mode, controls channel volume with extra gain/distortion above ~2 o'clock.481
Y Bknob—Controls filter B's Y parameter (typically resonance). Alternative assignments: vactrol decay time (#3), bandwidth (#7). In secondary mode, controls channel volume.481

Firmware history 4 versions

VersionReleasedNotes
42021-05-20Major firmware update titled 'Total Nightmare'. Manual cover indicates V.4 TOTAL NIGHTMARE / 03.02.2021.481
1.62017-02-26CV sampling frequency for X/Y jacks doubled; transistor ladder filter resonance improved; vactrol filter shortest decay time shortened; resonant vactrol filter improved; SVF high-pass bleed removed; exponential curve for Cabin Pressure knob; audio firmware update via Gate A input added; plate reverb hi-pass fixed and pre-delay secondary parameter added; VCF/VCFA mode revised.481
1.52016-12-29Filter ranges adjusted for #1/#5/#6 (now close fully); SVF #5-#7 glitches removed; VCFA mode volumes improved; resonant vactrol filter resonance glitch fixed; Tape Echo Cabin Fever inverted; logarithmic resonance/Y feel improved; improved VU meter logarithmic view; Silent Reset added (all 4 buttons >3s); Serial Mode and Stereo Mode improved.481
1.42016-11-25481

References 2

  1. [481]
    Endorphin.es Grand Terminal Manualmanual
    source 481 canonical ↗ archived ↗
    ● verified 2026-05-17
  2. [482]
    Endorphin.es Grand Terminal product pageproduct_page
    source 482 canonical ↗ archived ↗
    ● verified 2026-05-17