TLBX

Pindsvik Audio 2HP
UTILITY MULT MIXER BUFFER

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2HP precision toolbox: a 1-to-2 buffered mult, a 2-to-1 mix/adder, and a 2-to-2 adder/subtractor. Sections cascade through normalization, turning the module into a mult, mixer, 2x/1.5x/3x/6x voltage multiplier, octave transposer, range converter or comparator.

Patch Ideas · 6

★ Reference calibrator
Use TLBX as a bench reference: 1V on OUT1 tunes a VCO to an octave, 5V on OUT2 acts as a trusted source for attenuverter/offset calibration.
Walkthrough
  1. Leave MULT IN unpatched so the references are active.
  2. Patch MULT OUT1 (1V) into your VCO's V/Oct input.
  3. Play the VCO against a tuner and adjust the coarse knob until it sits exactly one octave above its 0V pitch.
  4. Swap the cable to MULT OUT2 (5V) to verify five octaves — if it drifts, recalibrate TLBX's trimmer as shown in the manual.
Signal out MULT OUT1 — rock-steady 1V; MULT OUT2 — rock-steady 5V (DC reference).
Listen for Silent DC. You'll see the VCO jump up exactly one octave (then five octaves) with no drift over time.
▸ Show diagram
Patch diagramPatch diagram with 3 modules and 2 connections. Modules: TLBX, VCO, Output. Signals: 1 audio, 1 pitch.TLBXVCOOutputMULT OUT11v/octV/Oct1v/octOutaudioInaudioaudiopitch
3x voltage multiplier (0-5V LFO becomes 0-15V)
Route a signal through MULT -> MIX -> DIFF and take A+B to triple the amplitude of a modulation source.
Walkthrough
  1. Patch your LFO or envelope into MULT IN.
  2. Leave MULT OUT1, MULT OUT2, MIX IN1, MIX IN2, MIX OUT, DIFF A and DIFF B all unpatched so every normalization cascades downstream.
  3. Take DIFF A+B as the output.
Signal out DIFF A+B — the input signal multiplied by 3 (clipping at the +/-12V rails if you push too hard).
Listen for A slow LFO going 0-5V will now swing 0-15V (rail-limited). Great for dramatic filter sweeps from gentle modulators.
▸ Show diagram
Patch diagramPatch diagram with 3 modules and 2 connections. Modules: TLBX, LFO, VCF. Signals: 2 pitch.TLBXLFOVCFMULT IN1v/octDIFF A+B1v/octOut1v/octCutoff1v/octpitch
One-octave transposer
Add the 1V reference to a V/Oct line on DIFF A+B (up an octave) while DIFF A-B gives the same line transposed one octave down.
Walkthrough
  1. Leave MULT IN unpatched so OUT1 reads 1V.
  2. Patch MULT OUT1 (1V) into DIFF B.
  3. Patch your sequencer's V/Oct into DIFF A.
  4. Patch DIFF A+B to one VCO for the up-octave voice.
  5. Patch DIFF A-B to a second VCO for the down-octave voice.
Signal out DIFF A+B — original pitch +1 octave; DIFF A-B — original pitch -1 octave.
Listen for A melody layered across three octaves with perfect tuning. Unpatch DIFF B to collapse both voices back to unison.
▸ Show diagram
Patch diagramPatch diagram with 5 modules and 6 connections. Modules: TLBX, Sequencer, VCO 1, VCO 2, Mixer. Signals: 2 audio, 4 pitch.TLBXSequencerVCO 1VCO 2MixerDIFF A1v/octDIFF B1v/octMULT OUT11v/octDIFF A+B1v/octDIFF A-B1v/octV/Oct1v/octV/Oct1v/octOutaudioV/Oct1v/octOutaudioInaudioaudiopitch
★ Bipolar to unipolar range converter
Turn a -5..+5V LFO into a clean 0-5V modulator for a unipolar destination by adding 5V and halving via MIX+DIFF.
Walkthrough
  1. Leave MULT IN unpatched so OUT2 is 5V.
  2. Patch MULT OUT2 (5V) into MIX IN1 — this adds 5V to the signal.
  3. Patch your bipolar LFO into MIX IN2.
  4. Leave MIX OUT unpatched so the sum cascades into DIFF.
  5. Patch DIFF A-B (which receives MIX OUT halved) to your destination.
Signal out DIFF A-B — a clean 0-5V version of a -5..+5V input.
Listen for A bipolar LFO now sweeps a filter or wavefolder that only responds to positive CV without clipping the bottom half.
▸ Show diagram
Patch diagramPatch diagram with 3 modules and 3 connections. Modules: TLBX, LFO, VCF. Signals: 3 pitch.TLBXLFOVCFMIX IN11v/octMIX IN21v/octMULT OUT21v/octDIFF A-B1v/octOut1v/octCutoff1v/octpitch
★ 5-channel mixer
Exploit every normalization to sum up to five CV or audio sources on DIFF A+B (with IN1 running at +6dB, the other four at unity).
Walkthrough
  1. Patch sources 1 and 2 into MULT IN and MULT OUT1 is left open (signal cascades into MIX).
  2. Patch sources into MULT IN, MIX IN1, MIX IN2, DIFF A and DIFF B — one per jack.
  3. Leave MULT OUT1/OUT2 and MIX OUT unpatched so the cascade sums everything through to DIFF.
  4. Take DIFF A+B as the master mix. MULT IN appears at roughly 2x, the other four at unity — attenuate source 1 upstream if you want unity gain on it too.
Signal out DIFF A+B — single mono sum of up to five inputs, DC-coupled so it works for audio or CV.
Listen for A full mini-mixer in 2HP. Pull any cable to that section's output to break its branch out of the mix.
▸ Show diagram
Patch diagramPatch diagram with 7 modules and 6 connections. Signals: 6 audio.TLBXSrc 1Src 2Src 3Src 4Src 5OutputMULT INaudioMIX IN1audioMIX IN2audioDIFF AaudioDIFF BaudioDIFF A+BaudioOutaudioOutaudioOutaudioOutaudioOutaudioInaudioaudio
CV comparator (zero-crossing gate)
Feed MIX OUT back into MIX IN2 to create a high-gain loop that slams to the rails, converting a bipolar CV into a hard +/-10V gate at each zero-crossing.
Walkthrough
  1. Patch your bipolar CV source (LFO, VCO, slow envelope) into MIX IN1.
  2. Use a short cable to patch MIX OUT back into MIX IN2.
  3. Take MIX OUT (or its doubled version on DIFF A+B) to your gate destination.
Signal out MIX OUT — approximately +10V when the input is above 0V, -10V when below 0V.
Listen for A smooth LFO becomes a square-wave gate. Slow LFOs produce long trigger windows; audio-rate inputs produce a squared-up sub-octave.
▸ Show diagram
Patch diagramPatch diagram with 3 modules and 3 connections. Modules: TLBX, LFO, Envelope. Signals: 2 audio, 1 pitch.TLBXLFOEnvelopeMIX IN11v/octMIX IN2audioMIX OUTaudioOut1v/octGateaudioaudiopitch

Behaviors

1V / 5V voltage references leave MULT IN unpatched

MULT OUT1 outputs 1V (<±1mV typ), MULT OUT2 outputs 5V (<±2.5mV typ). Used for tuning VCOs, calibrating attenuverters, driving quantizers to a known octave, or feeding the rest of the module as a DC source. The reference path is excluded from the inter-section normalization.

Section normalization cascade leave a section's output unpatched while its inputs are driven

MULT OUT1 unpatched -> mult signal sums into MIX OUT. MULT OUT2 unpatched -> mult signal sums into both DIFF outs. MIX OUT unpatched -> mix feeds DIFF A+B at x1 and A-B at x0.5. Breaking a cable into a downstream input breaks that section's input normalization.

Precision 2x multiplier (MIX) patch a signal into MIX IN1 only

With MIX IN2 unpatched, IN2 is normalized to IN1 and MIX OUT = 2 x IN1. Combined with the MULT-to-MIX cascade, a single input into MULT IN can reach 3x or 6x at the A+B output.

Adder / subtractor / inverter (DIFF) patch the DIFF section

Both inputs -> A+B is the sum, A-B is the difference. Only A patched -> both outs copy A (doubles as a 1-to-2 mult). Only B patched -> A+B copies B, A-B outputs -B, giving a clean signal inverter.

Octave transposer patch MULT OUT1 (1V ref) into a DIFF input and run V/Oct through the other

Adding or subtracting the calibrated 1V reference transposes a 1V/Oct pitch line by exactly one octave. Using MULT OUT2 (5V) the same way gives 5-octave shifts; doubling via MIX yields 2-octave shifts.

Voltage range conversion combine MIX doubling with a DIFF subtraction of 5V

0-5V -> -5..+5V by doubling then subtracting 5V. -5..+5V -> 0-5V by adding 5V and halving. TLBX replaces a pile of offset and scale utilities for bipolar/unipolar conversions.

Comparator via feedback patch MIX OUT back into MIX IN2 (or similar self-feedback)

DC-coupled, high-gain feedback through the mix path saturates to the op-amp rails, producing roughly +/-10V based on whether the input is above or below 0V. Good for hard thresholding CV into gates.

Controls

I/O

IN · 5

  • MULT IN audio / CV, DC-coupled, 100k input impedance CV
    Input to the 1-to-2 precision multiple. When unpatched, OUT1 and OUT2 become 1V and 5V references.
  • MIX IN1 audio / CV, DC-coupled, 100k input impedance CV
    First mixer input. When left unpatched, MIX OUT copies MULT IN (input normalization from MULT).
  • MIX IN2 audio / CV, DC-coupled, 100k input impedance CV
    Second mixer input. Normalized to IN1 when unpatched, so a signal on IN1 alone appears doubled at MIX OUT (precision 2x).
    NORM → MIX IN1
  • DIFF A audio / CV, DC-coupled, 100k input impedance CV
    First DIFF input. When both DIFF inputs are unpatched, DIFF takes its signal from MIX OUT (input normalization from MIX).
  • DIFF B audio / CV, DC-coupled, 100k input impedance CV
    Second DIFF input. If only DIFF A is patched, A+B copies A and A-B copies A. If only DIFF B is patched, A+B copies B and A-B outputs an inverted copy of B.

OUT · 5

  • MULT OUT1 (1V) buffered, zero-impedance output
    Buffered copy of MULT IN. When MULT IN is unpatched, outputs a 1V reference (typ. <±0.5mV, max <±1mV). If left unpatched while MULT IN is patched, the mult signal is also summed into MIX OUT (output normalization).
  • MULT OUT2 (5V) buffered, zero-impedance output
    Buffered copy of MULT IN. When MULT IN is unpatched, outputs a 5V reference (typ. <±1mV, max <±2.5mV). If left unpatched while MULT IN is patched, the mult signal is summed into both DIFF outputs (output normalization).
  • MIX OUT buffered, zero-impedance output
    Precision sum of MIX IN1 + MIX IN2. If MIX OUT is unpatched, the mix is passed to the DIFF section at full gain into A+B and halved into A-B (output normalization).
  • DIFF A+B buffered, zero-impedance output
    Precision sum of DIFF A and DIFF B.
  • DIFF A-B buffered, zero-impedance output
    Precision difference (A minus B). Combined with A+B gives a 2-to-2 adder/subtractor; can also act as an inverter when only B is patched.