toppobrillo-matrixplexer

Toppobrillo Matrixplexer

4x4 2D scanning matrix mixer with axis-independent transit modes.

24 HP Eurorack module

The Matrixplexer is a 24HP active 4-input by 4-output matrix mixer with built-in 2D scanning. Each of the 16 cross-points has its own attenuator and a low-noise linear VCA, so any input can be routed to any output (or to several at once) under CV control. Independent X (row) and Y (column) transit engines move the active scan position around the grid using one of three modes (Scan, Stack, Scroll), with shape control over the crossfade slope between channels. A clock input syncs all motion to your patch.

Features

  • Active 4x4 cross-point matrix with low-noise linear VCAs at every node
  • DC-coupled inputs and outputs (audio and CV both work)
  • Per-output hard-mute switches (the four I/O toggles)
  • Two independent axes (X = rows, Y = columns) each with their own slider, mode switch, shape, CV input and attenuverter
  • Three transit modes per axis: Scan (exclusive), Stack (sequential), Scroll (through-zero LFO)
  • Shape control morphs the cross-point crossfade from hard-switch to linear to gate-all
  • External clock input syncs all transit motion
  • Per-row Row CV inputs gate or offset rows individually
  • Per-column Mix CV inputs gate or offset columns individually
  • Global MIX CV In sums across all four column scan CVs
  • Orange channel-active LED at every cross-point to visualise scan motion
  • Through-zero scroll LFOs run in either direction continuously

Controls & Jacks (51)

  • MIX CV In
  • A Out
  • B Out
  • C Out
  • D Out
  • Y-SHP CV In
  • CLK In
  • A Mix CV In
  • B Mix CV In
  • C Mix CV In
  • Y-SHP
  • Y Mode
  • Y Mode LED
  • Y CV Attenuator
  • IN 4
  • IN 3
  • IN 2
  • IN 1
  • Row 4 CV In
  • Row 3 CV In
  • Row 2 CV In
  • Row 1 CV In
  • A4 Level
  • B4 Level
  • C4 Level
  • D4 Level
  • A3 Level
  • B3 Level
  • C3 Level
  • D3 Level
  • A2 Level
  • B2 Level
  • C2 Level
  • D2 Level
  • A1 Level
  • B1 Level
  • C1 Level
  • D1 Level
  • X-SHP CV In
  • X-SHP
  • X CV Attenuator
  • X CV In
  • Y CV In
  • Mix CVS Mode— Selects how the Mix CV inputs are routed: through (each Mix CV applies only to its labeled output) or summed (all Mix CVs act on every outpu
  • A I/O Mode— Selects whether channel A's column acts as an input column (signal flows down through the matrix) or an output column (signals flow into A O
  • B I/O Mode— Selects whether channel B's column acts as an input column or an output column.
  • C I/O Mode— Selects whether channel C's column acts as an input column or an output column.
  • D I/O Mode— Selects whether channel D's column acts as an input column or an output column.
  • X Mode— Three-position toggle controlling the X fader's crossfade behavior: stepped (snaps to columns), interpolated (smooth crossfade), or single-c
  • X— Horizontal crossfade between matrix columns. Sweeps the active column from A→D continuously (or stepped, per X Mode). Combine with X CV In +
  • Y— Vertical crossfade between matrix rows. Sweeps the active row from 1→4 continuously (or stepped, per Y Mode). Combine with Y CV In + Y CV At

How-To Guides

  • Static 4-to-4 mix
  • Clocked auto-panning
  • 2D morph between four mixes
  • CV-controlled quad send/returns
  • Feedback loop with row gating

Explore the interactive Matrixplexer panel on BleepDex — tap any control to learn what it does.

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