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Q106 Oscillator (VCO)

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Q106 Oscillator Module

The Q106 Oscillator is the foundation of any synthesizer providing the basic waveforms used to construct sounds. With a total range of .05hz to 20kHz+, the Q106 operates as a powerful audio oscillator and a full-featured LFO.

  • Precise tracking with temperature compensation
  • Pure analog circuitry
  • Rock solid stability
  • Sine, triangle, saw, ramp, pulse outputs
  • 2 fixed 1V/Octave control inputs and 1 variable
  • Variable linear control input
  • Manual and voltage controlled pulse width (PWM)
  • Quick, precise range switching
  • Hard sync
  • Add soft sync, waveform switching, inversion and attenuating with the Q141 Aid module
  • Add waveform mixing with the Q161 Mixer module
Q161 Oscillator Mixer Q141 Oscillator Aid

Add waveform switching, variable output, and soft-sync with the Q141 Oscillator Aid Module, and waveform mixing with the Q161 Module.

CRS - The Q106 now includes the CRS (Calibrated Range Switch) which use to be optional.

$225.00 USD
  • RD Wrote: Beautiful Roger!! I have posted this Many Times In many Forums. You will Not find a better sounding MORE STABLE VCO than the Q106 at ANY PRICE!!!!
  • VCO hard sync with modulation of sync amount & reverb q106t.mp3, Patch
  • Slew to VCO sine to ladder filter w/vibrato & reverb q106k.mp3, Patch
  • Saw to ladder filter like trumpet q106q.mp3
  • Slew to VCO pulse w/vibrato no filter q106p.mp3
  • VCO hard sync with repeating sequence w/sweeping sync q106u.mp3, Patch
  • Terje Wrote: I just wanted to tell you that the dotcom VCO stayed right in tune and scaling all through the shipment, setup, soundcheck, waiting and concert. As I had a total of 18 VCOs from 8 different manufacturers to tune (and I had to re-scale some), I was quite thankful for the dotcom stability.
  • Panel Size:  Dual width 4.25"w x 8.75"h
  • Response:  1/V per Octave
  • Frequency Range:  .05hz to 20khz
  • Output Waveforms:  Sine, Triangle, Saw, Ramp, Pulse
  • Waveform Levels:  10V PP
  • Sine Waveform THD:  3%
  • Pulse Waveform Duty Cycle:  5% to 95%
  • Power:  +15V@30ma, -15V@30ma, +5@5ma.
  • Bernie Wrote: Q106/Q141 VCOs have excellent rise times with no ring or overshoot which make for very crisp clear tone and they track like a bloodhound to boot.

Oscillators are the main source of sound in a synthesizer. The waveforms are then routed to filters and other modules for modification. Oscillators can also be used to modulate other module's parameters or to trigger envelope generators and sequencers.

Exponential Pitch Control
Pitch of the oscillator is usually controlled by a keyboard but can also be controlled by a sequencer or any module's output. Normally pitch is controlled by a keyboard that produces 1 volt per octave. Each additional volt results in a 2x increase in pitch (frequency). This is called exponential or 1V/Octave response. The main reason for this is to allow controllers to produce the entire audio range of frequencies with lower voltages. A 10 octave range requires only 10 volts of control voltage. If the response was linear then 10 octaves of range would require 512 volts of control signal. There are a total of 3 exponential pitch control connectors on the oscillator and one has an adjustable response. All of these inputs can be used at the same time if needed. In most cases you will simply connect the output from your keyboard into one of the 2 non-adjustable 1V/Octave inputs. It's also common to modulate from another oscillator into the adjustable exponential control connector.

Linear Pitch Control
There is also a pitch control connector which has a linear response. This is normally used to produce vibrato which is a modulation of pitch. The amount of the affect of the modulation signal upon pitch can be adjusted with the front panel control.

Pulse Width Modulation
The width of the pulse waveform can be adjusted manually or from an external control signal such as another oscillator. This produces interesting effects similar to a violin. You'll have to experiment to see how this sounds.

Using the Oscillator to Modulate
The Q106 Oscillator is designed to produce both audio signals and slow moving signals to modulate other modules. Normally this will be done using the 'Low' range which will give you frequencies below 32hz. All of the output waveforms are available and can be used to control an oscillator's pitch (vibrato), an amplifier (tremolo), or a filter's cutoff frequency or resonance. You can also use the oscillator to trigger an envelope generator or to start and stop a sequencer.

All outputs are available at the same time and can be patched anywhere you like. Use a Q125 Signal Processor to attenuate, amplify, invert or offset any waveform from the oscillator.

The Oscillator has a Hard Sync input which is used to synchronize multiple oscillators. Use the pulse waveform from a slower oscillator into the Hard Sync inputs on higher frequency oscillators to synchronize them. This will eliminate beating. Strange effects can be created by synchronizing oscillators at non-multiple frequencies.

You can take one of the outputs from the oscillator and patch it back into the adjustable exponential response connector or the linear response connector and completely change the waveform. If you have an oscilloscope you can see exactly what's happening. Almost any type of waveform can be produced this way.


The following tests were done on a Q106 Oscillator taken right off the production line. No special calibration, parts, procedures, or modifications were used.

Tracking Accuracy
Tracking accuracy determines how closely your oscillators track the keyboard. Human hearing is very sensitive to pitch and some people can discern differences as low as .2%. Tracking is most important on frequencies from 32hz to 4096hz (7 octaves). We think this is the most important parameter of an oscillator.

Test Equipment Used (all have recent calibration):
   HP 5335a 9 Digit Frequency Counter
   Fluke 3330b Voltage Calibrator

Q106 Tracking Accuracy
DesiredActual% Error

Temperature Drift
When using your synthesizers in a hot environment temperature drift can be a problem. The Q106 Oscillator has special circuitry to compensate for this drift.

Test Equipment Used (all have recent calibration):
   HP 5335a 9 Digit Frequency Counter
   Ransco CC-580 Digital Oven

Q106 Temperature Drift
Freq/Temp #1Freq/Temp #2% Error

Waveform Purity
Analog waveforms are not supposed to be perfect but we don't want strange artifacts that add unwanted harmonics or ones that can be heard when modulating at low frequencies.

Test Equipment Used (all have recent calibration):
   HP 5335a 9 Digit Frequency Counter
   HP 8903b Audio Analyzer
   Fluke 3330b Voltage Calibrator

Q106 Sine Distortion
Freq% Distortion

Power Supply Rejection
You don't want your oscillator pitch changing when the system's power supply voltages vary. The Q106 uses precision voltage references instead of relying on the system's power supply voltages.

Test Equipment Used (all have recent calibration):
   HP 5335a 9 Digit Frequency Counter
   HP 3455a 6.5 Digit Voltmeter

Q106 Power Supply Rejection
+15 Voltage RailPitch
-15 Voltage RailPitch
  • John Wrote: If there is one thing I love about this synth (there are several, actually) it is the oscillators. Record. Turn off synth. Come back next day. Turn on synth. Record. No need to retune in nearly every case.

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