Eurorack Thru Zero Oscillator

GB Volt Age Electronic Musical Instruments introduces Osi-Op      11/08/22

The first company to produce synthesizers and electronic musical instruments for commercial purposes in Turkey, VAEMI (Volt Age Electronic Musical Instruments) has introduced Osi-Op, which they say is the first Eurorack module with high-quality Thru Zero FM and a different Waveshape feature. Here's more details in their own words...

This module is made by combining through-hole quality components and it is handmade. Osi-OP, which we regard as an analog reflection of the new era of digital electronic music, is an analog and voltage-controlled oscillator module. It was designed in Eurorack format and it has a width of 14hp. It has Thru Zero FM Input and a Waveshape Output, which can be used for morphing, and these are two of the most important features of this product. From a first impression, it may look like an oscillator that is appropriate for subtractive synthesis. However, it was actually designed to be used for additive synthesis. Thanks to Thru Zero FM, this oscillator can regard oscillators with Sine Wave as analog operators.

You can even prepare your synthesizer patch without using the classic subtractive resonant filter. The most important aspect of Thru Zero FM is that there is no tune drift when you increase the modulation rate. For this reason, Thru Zero attenuator (TZ FM potentiometer) can almost be used like a filter itself. In addition to Square, Saw, Triangle, and Square Sub oscillator outputs, it has a Sine Wave Output, which was designed with JFET transistors and has a very low distortion rate, and a Waveshape Output, which was designed with Sine-Triangle and can be used for morphing. It also has a Wave Shape Input. It is connected to this input via the Triangle Wave circuit board inside.

Sine Wave is fixed on Wave Shape but you can forward it to the other WS Input by patching other waveforms, and you can morph between two waveforms. The pulse width of the Square Wave can be adjusted. The same knob is the morphing knob of the Waveshape Output. Since the oscillator has tempco, there is a 1V/OCT calibrated CV Input that is sensitive to heat. It can perfectly stay in tune up to 3.5 octaves. In addition, for FM, there are two separate CV Inputs, Exponential and Thru Zero. While Exponential FM CV Input can take all types of DC and AC voltages, Thru Zero FM CV Input can only be used for AC audio rate signals. Also, when you enter a waveform on Thru Zero FM CV Input, oscillators are soft-synced automatically. With 1V/OCT CV Input, you can adjust the frequency of the oscillator; and with Exponential FM CV Input, you can easily add an LFO or Envelope Generator. Square Wave Sub OSC Output, which is completely synced with fundamental frequency and can give an octave lower than the fundamental, will help you a lot to create strong modern synth-bass sounds. It is made with NOS integrated. When the oscillator is FM modulated, the Sub OSC never gets negatively affected by this modulation; and it can maintain giving the frequency clearly. You can also switch the oscillator to the LFO mode. You can create subtractive syntheses by using two or more of these oscillators or by mixing these waveforms.

The main reason why this oscillator was designed, as its name shows, is to enable the creation of complex FM patches and sounds by using 2-3 or more of these oscillators, just like Operator FM. While Thru Zero FM increases the modulation, it can maintain giving the same frequency without losing the adjusted frequency; and you can add harmonics to the sound musically. The module has 5 knob controls, 4 CV Inputs, an input for Waveshaper, and 6 ±5V waveform outputs. Osi-OP, which is handmade and produced with the help of Through Hole technology, is a product consisting of electronic components that are carefully tested.

Technical Specifications

Knob 1 - Tune
Knob 2 - Fine Tune
Knob 3 - Thru Zero FM
Knob 4 - Exponential FM
Knob 5 - Pulse Width Modulation / Waveshape Morphing

Tune Range 3.5hz - 7khz
1V/OCT CV Input (±8V)
Exponential CV Input (±8V)
Thru Zero FM Input (±8V) (AC Coupled)
PWM / WS Morphing CV Input (±5V)
WS Morphing Wave Input
Sine Wave Output (±5V / 10Vpp) (1k ohm)
Triangle Wave Output (±5V / 10Vpp) (1k ohm)
Sawtooth Wave Output (±5V / 10Vpp) (1k ohm)
Square Wave Output (±5V / 10Vpp) (1k ohm)
Square Sub OSC Output (10Vpp) (1k ohm)
Waveshape Output (±5V / 10Vpp) (1k ohm)
LFO / OSC Switch
+12v 45mA
-12v 35mA
Derinlik 40mm (from panel to ribbon cable (including ribbon cable size)

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