Pittsburgh Modular Taiga Desktop Analogue Semi-Modular Synth

The Digital Control Functions built into the Taiga include a MIDI-to-CV converter, tap-tempo clock source, octave shifting, a 32-step sequencer/arpeggiator, and a multifunction modulation tool with a clock synced LFO, decay envelope, and random voltage generator.

• The sounds generated by the three Taiga oscillators are the culmination of years of research and design. The cascading wave shaping circuitry we have created is the foundation of our organic analog synthesis concept.
• The unique sound of Taiga starts with a refined version of Pittsburgh's temperature stabilized, analog VCA saw-wave oscillator core. The internal signal path of the Taiga oscillators passes the core saw waveform through up to 4 additive wave shapers before reaching the output. Waveform names should be thought of as more of a guide to harmonic density than the definitive shape of the output wave. During the design phase, we began calling the initial clean geometric waveforms (sine, triangle, saw, pulse) seed waves because the shapes of the waveforms available at the output are very different than the internal source wave. As an example, if all the wave shaping is turned down, the output of the triangle wave looks more like a sine wave from the output of the sine wave on an oscilloscope. Because of the intensive wave shaping, the seed wave is simply one of several factors that determine the shape and sound of the output.
• The internal signal path of the Taiga oscillators is more complex than typical oscillators. The waveform passes through up to 4 wave shapers on its way to the output. All of the wave shapers before the wave folder circuit are designed to manipulate the waveform in ways that allow it to interact with the wavefolder in different ways.

• The dual mixer section is deeper and more useful than it may appear. It is a 2 channel mixer and a 3 channel mixer joined together and capable of mixing both audio or control voltages.
• The preamp uses a high gain, soft clipping overdrive limiter circuit to increase the level of audio signals. The preamp can be used to cleanly increase the level of external audio to internal signal levels, or it can be used as an overdrive/limiter for internal signals.

LFO

• The LFO module is an analog, dual-range, low-frequency oscillator with +/-5 volt triangle and square wave outputs. Perfect for long sweeps or audio-rate frequency modulation.
• LFO Ranges: High: 2 Hz to 500 Hz, Low: 41 seconds to 5 Hz

Noise

• The transistor core analog noise source is pitched somewhere between pure white and pink noise. Perfect for percussion or adding a bit of edge to a sound.

Sample & Hold

• The Sample & Hold circuit samples the voltage patched to the [Sample and Hold input jack and outputs that voltage until a new sample voltage is taken. A sample is taken when the Sample and Hold input jack receives a positive gate or trigger. The sample source can be audio or cv. The output is sent to the Sample and Hold output jack.

Mixer/Splitter

• The Mixer/Splitter section offers both mixing and signal splitting with a two-channel unity gain mixer and a set of individually buffered outputs. This section can be used as a two channel mixer, buffered signal splitter, or both.

A distinct sound that has been tweaked to perfection. It offers a warm, organic sweep through the full frequency range. The lowpass filter is gummy and relaxed while the highpass is clean and defined. The goal was to produce a filter that did not have a dead spot, where every turn of the frequency knob produces something interesting.

Filter Response

• The PGH Filter module is a voltage controlled, analog, 2-pole, 12 dB state-variable filter. State variable topology offers several filter output responses, high-pass, band-pass, low-pass, and notch.

Filter Resonance

• One of the more interesting aspects of a state-variable filter is the ability to offer near-infinite resonance without self-oscillating by amplifying a narrow band of frequencies around the filter Cutoff frequency. This helps to shape the smooth, musical sound of the PGH Filter. The amount of resonance available is headroom dependent. Smaller incoming audio signals allow more headroom for resonance and larger incoming audio signals allow less headroom for resonance.

• The ADSR modules are a pair of four-stage ADSR envelope generators that smooth the shape of the incoming gates and triggers to produce a more expressive instrument. The envelope outputs can be used to control the amplitude of an oscillator, the cutoff frequency of a filter or any other function on a module that accepts control voltages.
• The envelopes in Taiga are based on the Lifeforms SV-1 ADSR and are designed to be snappy and percussive. Small adjustments to the [ADSR Attack Knob] will reduce this effect and smooth out the sharp attack.

The Dynamics module plays a large part in shaping the output of Taiga by utilizing a unique processing circuit that adds dimension to the sound. The Dynamics circuit is unique in the way that it simulates the characteristics of the natural world. When used in lowpass gate mode, louder sounds contain more harmonic content and quieter sounds contain less harmonic content. This is not the case when using VCA mode. VCA mode simply changes the loudness of the sound without modifying the harmonic content. There is no reason that synthesizers need to simulate the real world but because of how it affects the harmonic content of sound, a low-pass gate sounds more organic or natural compared to a standard VCA.

• The Echos module utilizes a pair of 4096-stage BBD chips to produce a voltage controllable analog delay signal. Clean delay time can vary from 16 to 250 ms. The maximum delay time can be increased using the Echos Time CV input jack. The delay time maxes out at 500 ms but the increased time comes at the cost of fidelity and high-frequency clock-noise bleed.
• The name BBD stands for bucket-brigade device in reference to a line of people passing buckets of water to quickly extinguish a fire. Each stage of a BBD chip contains a single capacitor. Pairing two chips together creates a chain of 8192 capacitors. Like the water buckets, an audio signal is passed from capacitor to capacitor within the BBD chips once every clock step. A slower clock produces a longer delay and a faster clock produces a shorter delay.

Line level and headphone outputs. The line level output is monophonic. The headphone output is dual monophonic with the same monophonic signal routed into both the left and right channels.