alm-busy-circuits-tazm-o

ALM Busy Circuits TAZM-O

Analog thru-zero FM oscillator with morphing shape and sub octaves

12 HP Eurorack module

The TAZM-O is an analog triangle core oscillator featuring through-zero frequency modulation. It combines a continuous morphing wave shape control (inspired by the Serge NTO), dual SH-101 style sub octave outputs, voltage controlled FM Index, a built-in output VCA, and voltage controlled octave transposition. The primary shape output morphs between sine/triangle, saw, and pulse waves before passing through the integrated VCA. Additional dedicated outputs provide direct sine (or triangle), saw, and two sub-octave pulse signals. An LFO mode lowers the frequency range for modulation duties.

Features

  • Analog triangle core oscillator with through-zero frequency modulation
  • Continuous morphing wave shape: sine/triangle → saw → variable pulse (10-90% duty cycle)
  • Shape control inspired by the Serge NTO
  • Built-in linear output VCA with CV control on the primary Shape output
  • Dedicated simultaneous outputs: sine (or triangle), saw, sub-1, sub-2, and shape
  • Dual sub-octave pulse outputs (SH-101 style): Sub-1 at -1 oct, Sub-2 at -2 oct
  • Voltage controlled FM Index for easy dynamic FM patching
  • Octave transpose CV input (0/+1/+2 octaves, similar to Akemie's Castle)
  • Hard sync input for classic timbral effects
  • LFO mode (0.1Hz-30Hz) with bipolar LED indication
  • Rear PCB switches: sine/triangle selection, Sub-2 duty cycle (50%/75%)
  • V/Oct tracking across ~8 octaves with rear calibration trimpots

Controls & Jacks (22)

  • V/Oct— 1V/octave pitch CV input, ~8 octave range
  • Coarse Tune— Coarse frequency control, ~7 octave range
  • LFO LED Green— Indicates negative sine polarity in LFO mode
  • LFO LED Red— Indicates positive sine polarity in LFO mode
  • LFO— Latching button to activate LFO mode (0.1Hz-30Hz range)
  • TZFM— Through-zero frequency modulation input, routed via internal index VCA
  • Fine Tune— Fine frequency control, ~1 octave range
  • FM Index— Controls depth of through-zero FM via internal VCA
  • Shape— Continuous morphing: sine/triangle → saw → pulse (10-90% duty cycle)
  • FM Index CV In— CV input for FM index depth (0-5V), with attenuator
  • FM Index CV Attenuator— Attenuator for FM Index CV input (0-5V)
  • Shape CV Attenuator— Attenuator for Shape CV input (0-5V)
  • Level— Controls built-in linear output VCA level; functions as attenuator when CV patched
  • Oct— Octave transpose CV input: ~1V = +1 oct, ~3V = +2 oct
  • Sync— Hard sync input, resets oscillator core on rising edge
  • Shape CV In— CV input for waveform shape modulation (0-5V), with attenuator
  • Level CV In— CV input for output VCA level (0-5V)
  • Sine Out— Dedicated sine (or triangle, via rear switch) output
  • Sub-1 Out— Sub octave -1, fixed 50% duty cycle pulse
  • Sub-2 Out— Sub octave -2 pulse, 50%/75% duty cycle via rear switch
  • Saw Out— Dedicated sawtooth wave output
  • Shape Out— Primary morphing waveform output through built-in VCA

How-To Guides

  • Basic Pulse Width Modulation
  • Dual Oscillator FM Voice
  • Self-Patched Shape Modulation
  • Self-Patched Amplitude Modulation
  • Hard Sync Timbral Sweep

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

8c571ce