endorphin-es/golden-master

Golden Master

Endorphin.es

Stereo multiband processor combining three-band EQ, three-band compression, and mid/side processing in a compact performance-oriented 6HP module. Inspired by classic studio mastering processors and radio loudness units from the 90s. Features 24-bit/96kHz audio I/O with 32-bit internal processing and a final brickwall limiter.663

Capabilities 5

Brickwall Limiterbrickwall-limiter
1 ms look-ahead brickwall limiter at the end of the signal chain; sets maximum output level.663
Mid/Side Processingmid-side-processing
Independent per-band mid/side processing for LOW, MID, and HIGH. LOW band uses classic M/S narrowing/widening. MID and HIGH bands use decorrelation. HIGH band additionally uses delay-line-based widening with LFO modulation.663
Multiband Compressormultiband-compressor
Three-band stereo compressor with one-knob character control per band and a global IN GAIN/THRESHOLD macro. Includes automatic makeup gain and compressor must be enabled per band via long press.663
Multiband EQmultiband-eq
Three-band stereo equalizer with crossover points at ~300 Hz and ~3 kHz. Each band independently boostable up to +8 dB or cuttable up to -20 dB.663
Voltage-Controlled Amplifiervca
Post-VCA CV input with 0–5V range, placed after VCA and before the VOLUME knob.663

Jacks 5 — 3 in / 2 out

NameSignalVoltageDescription
Inputs (3)
IN LEFTaudio-6.5V to 6.5VLeft (mono) stereo audio input. Normalled to IN RIGHT when no cable is plugged into IN R jack.663
IN RIGHTaudio-6.5V to 6.5V663
VCA CVcv0V to 5VPost-VCA, pre-VOLUME knob CV input. 0V = silence, 5V = full volume.663
Outputs (2)
OUT LEFTaudio—Final left stereo audio output. Supports pseudo-balanced use with 1/8" TRS cables, with ring connected to ground for noise cancellation.663
OUT RIGHTaudio—Final right stereo audio output. Supports pseudo-balanced use with 1/8" TRS cables.663

Parameters 9

NameTypeRangeBehavior
HIGH BANDknob-20dB – 8dBIn EQ mode: adjusts HIGH band gain (-20 dB CCW, +8 dB CW, 100% at center). In COMPRESSOR mode: sets compression character for the HIGH band. In MID/SIDE mode: adjusts stereo width of the HIGH band from mono (CCW) to wide (CW).663
Zones
mid-side
Narrow
Wide
  • Narrow -100–0%Narrows the HIGH band stereo image toward mono. At minimum (full CCW), the band becomes fully mono.663
  • Wide 0–100%Expands HIGH band stereo image using delay-line-based decorrelation with LFO modulation, adding air, shimmer, and animated spaciousness.663
HIGH MUTE/COMPRESSOR ENABLEbutton—Single press: mutes the HIGH band (LED semi-dimmed). Long press (>1.5 s): enables compressor for the HIGH band (LED fully lit).663
IN GAIN / THRESHOLDknob—Global compression depth macro for all three bands. At full CCW, compression is minimal. Turning CW lowers the effective threshold making the compressor work harder. Near full CW, also adds a small amount of digital gain. Works globally regardless of selected MODE.663
Zones
Light
Light/Medium
Medium
  • Light -100–-34%Open, dynamic, lightly processed — compression is minimal.663
  • Light/Medium -34–0%Gentle smoothing and polish.663
  • Medium 0–32%Balanced glue, density, and control.663
LOW BANDknob-20dB – 8dBIn EQ mode: adjusts LOW band gain (-20 dB CCW, +8 dB CW, 100% at center). In COMPRESSOR mode: sets compression character for the LOW band. In MID/SIDE mode: adjusts stereo width of the LOW band from mono (CCW) to wide (CW).663
Zones
mid-side
Narrow
Wide
  • Narrow -100–0%Narrows the stereo image toward mono. At minimum (full CCW), the band becomes fully mono.663
  • Wide 0–100%Expands stereo image using classic mid/side processing with intentionally limited widening range. If the LOW signal has no side component, effect is minimal.663
LOW MUTE/COMPRESSOR ENABLEbutton—Single press: mutes the LOW band (LED semi-dimmed). Long press (>1.5 s): enables compressor for the LOW band (LED fully lit). Compressor parameter editing via the LOW band knob is only possible after enabling via long press.663
MID BANDknob-20dB – 8dBIn EQ mode: adjusts MID band gain (-20 dB CCW, +8 dB CW, 100% at center). In COMPRESSOR mode: sets compression character for the MID band. In MID/SIDE mode: adjusts stereo width of the MID band from mono (CCW) to wide (CW).663
Zones
mid-side
Narrow
Wide
  • Narrow -100–0%Narrows the MID band stereo image toward mono. At minimum (full CCW), the band becomes fully mono.663
  • Wide 0–100%Expands MID band stereo image. First enhances existing side signal; further CW introduces decorrelation of the mono mid to stereo.663
MID MUTE/COMPRESSOR ENABLEbutton—Single press: mutes the MID band (LED semi-dimmed). Long press (>1.5 s): enables compressor for the MID band (LED fully lit).663
MODEbutton—Short press cycles through three editing modes: EQ (blue LED), COMPRESSOR (red LED), and MID/SIDE (red LED). Switching modes changes what the LOW/MID/HIGH knobs edit; all three processing sections remain active simultaneously.663
VOLUMEknob—Final output volume control. Maximum at full CW, silent at full CCW.663

Firmware history 1 version

VersionReleasedNotes
X!2026-04-22IN GAIN knob now works as a global compressor macro control (not just simple input gain), controlling overall compression depth for all three bands at once.663

References 2

  1. [663]
    Endorphin.es Golden Master 3U/1U Manualmanual
    source 663 canonical ↗ archived ↗
    ● verified 2026-05-21
  2. [664]
    Endorphin.es Golden Master product pageproduct_page
    source 664 canonical ↗ archived ↗
    ● verified 2026-05-21