ALM Busy Circuits TAZM-O

Analog Thru-Zero Oscillator with Dynamic FM - 12HP

• Triangular-wave-based analog oscillator with thru-zero FM
• FM modulation index controllable manually and via voltage
• Continuous waveform morphing inspired by the Serge NTO: sine, triangle, sawtooth, pulse, and square
• Dual SH-101-style sub-1 and -2 octave outputs with variable pulse width
• Integrated output VCA on the main output
• Voltage-controlled octave transposition (0, +1, +2 octaves), hard sync, and LFO mode
• Compact 12 HP format, suitable for skiff cases

The ALM Busy Circuits TAZM-O is a triangular-core analog oscillator with thru-zero frequency modulation, bringing together some of the most beloved features of classic VCOs in a single 12 HP module. The continuous waveform morphing is inspired by the Serge NTO, the sub-octave outputs are modeled after the Roland SH-101, the voltage-controlled FM index draws from large, complex oscillators, and the CV-controlled octave transposition echoes the multipliers found in Akemie’s Castle, ALM’s digital FM VCO. The result is a versatile main oscillator, capable of shifting from classic timbres to rich, metallic FM textures.

Serge NTO-style continuous waveform

The main output freely switches between sine, triangle, sawtooth, pulse, and square waves, with both manual and voltage-controlled adjustment. By modulating the “shape” parameter, you achieve a continuous timbral evolution, which keeps the sound alive even with a minimalist patch. The signal then passes through the built-in output VCA, allowing for level control directly on the module.

Direct Outputs and SH-101-Style Dual Sub-Octave Outputs

In addition to the main output, there are dedicated outputs for sine, triangle, sawtooth, and square waves, plus two sub-octave outputs at -1 and -2 octaves with variable pulse width in the style of the SH-101. This offers the flexibility of traditional VCOs, ideal for full-bodied bass sounds and for summing waveforms in an external mixer.

Through-zero FM with voltage-controlled modulation index

The thru-zero FM input features both manual and voltage-controlled modulation index. By pairing the TAZM-O with a second oscillator as a modulator, you can quickly and easily achieve FM timbres that remain in tune even at high modulation indices—a hallmark of thru-zero FM. By modulating the modulation index over time, the FM becomes dynamic: from clean sounds to bells, all the way to rough and complex textures.

CV Octave Transposition and Hard Sync

The octave transposition CV input shifts the oscillator by 0, +1, or +2 octaves—a unique solution for crisp melodic leaps and sequencer-driven arpeggios. The V/oct input covers approximately 8 octaves, while the hard sync input unlocks classic aggressive sync timbres.

12 HP Eurorack Main Oscillator

Designed to be the main VCO of your system, the TAZM-O offers a wide range of timbres and great patching flexibility in a relatively compact format. The LFO mode with bipolar LED indication also transforms it into a modulation source, while the rear switches allow you to select the Sub-2’s pulse width and choose between sine or triangle waveforms.

Technical Specifications

• Brand: ALM Busy Circuits
• Model: TAZM-O
• Type: analog oscillator for Eurorack
• Core: analog, triangular
• Main Waveform: Continuous morphing between sine, triangle, sawtooth, pulse, and square waves, with manual and voltage-controlled adjustment
• FM: thru-zero, manual and voltage-controlled modulation depth
• Dedicated outputs: sine or triangle, sawtooth, square, sub-1 octave, sub-2 octaves
• Main output with integrated level VCA
• V/oct input: approximately 8 octaves of range
• Octave transposition CV input: 0, +1, +2 octaves
• Hard sync input
• LFO mode with bipolar LED indicator
• Rear panel switches: Sub-2 pulse width, sine or triangle wave selection
• Power supply: +12 V 70 mA, -12 V 60 mA
• Dimensions: 12 HP
• Depth: 38 mm, suitable for skiff cases
• Reverse polarity protection
• Made in England