Controls and Connectors

There are 6 sections (listed top to bottom)
- Frequency Range Section
- Hard Sync Section
- Linear Frequency Control Section
- Pulse Width Control Section
- Exponential Frequency Control Section
- Output Section


Frequency Range Section
Frequency Range Control

Selects octaves from 32hz to 512hz with a 'low' setting for modulations.
Accuracy is 1% (Increase to .1% using the Q106CRS)
Frequency Control
Allows fine control of pitch over 1 octave.

Hard Sync Section
Hard Sync Connector

Allows the oscillator to be syncronized with other oscillators to prevent beating and to create strange effects.

Linear Frequency Control Section
Linear Frequency Control Connector

Allows external control of pitch with a linear response.
Linear Frequency Level Control
Determines the amount of affect that the linear control voltage has upon pitch.

Pulse Width Control Section
Pulse Width Control Connector

Allows external control of pulse width.
Pulse Width Level Control
Determines the amount of affect that the pulse width control voltage has.
Pulse Width Control
Allows manual setting of pulse width.

Exponential Frequency Control Section
1V/Octave Connectors (2)

Allows external control of pitch with an exponential response (usually from keyboards)
Adjustable Exponential Connector
Allows external control of pitch with an exponential response.
Exponential Frequency Level Control
Determines the amount of affect that the exponential control voltage has upon pitch.

Output Section
Sine

Pure mellow sounding waveform with almost no harmonics. Flute-like.
Triangle
Mellow sounding waveform with some harmonics.
Saw
Buzzy sounding waveform with many harmonics. Brass horn-like.
Ramp
Inverse of Saw. Sounds the same but useful for modulation.
Pulse
Hollow sounding waveform with many harmonics. Width can be controlled. Woodwind-like.

Q141 Oscillator Aid
Use the Q141 aid module next to your Q106 oscillator for additional functionality including a soft sync input with amount control, waveform selector, amplitude adjustment, and inverted outputs.

Price
$195.00 US.

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.

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.

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.

Waveforms

Performance
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
Desired	Actual	% Error
32hz	32.07hz	+0.22
64hz	64.16hz	+0.25
128hz	128.2hz	+0.16
256hz	256.2hz	+0.08
512hz	511.9hz	-0.02
1,024hz	1023.2hz	-0.08
2,048hz	2046hz	-0.09
4,096hz	4094hz	-0.05
8,192hz	8236hz	+0.5
16,384hz	16778hz	+2.3

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 #1	Freq/Temp #2	% Error
32.03hz@80ºf	32.18hz@100ºf	+0.5
512.3hz@80ºf	512.4hz@100ºf	+0.02

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
64hz	3.31
512hz	3.26
2048hz	3.01

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 Rail	Pitch
+15.027	512.1hz
+14.508	512.1hz
+15.514	512.1hz
-15 Voltage Rail	Pitch
-15.059	512.1hz
-14.556	512.1hz
-15.499	512.1hz

Usage and Patch Tips

Basics
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.

Outputs
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.

Sync
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.

Feedback
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.

Q141 Oscillator Aid

Add features to your Q106 Oscillator by coupling it to the Q141 oscillator aid. Adds:

• Soft Sync input and amount control
• Waveform selector switch
• Square wave (50% duty cycle pulse)
• Waveform attenuator
• Positive and negative waveform outputs

See the Q141 Module Page for more information.

    Maximum Features

Q161 Oscillator Mixer

Add waveform mixing to your Q106 Oscillator by coupling it to the Q161 oscillator mixer. Just dial in the amount of Sine, Triangle, Ramp and Pulse waveforms to create unusual sounds and modulation sources.

See the Q161 Mixer Page for more information.

    Mixing without Cables

Yes, you can use both the Q141 and the Q161 with a Q106 Oscillator at the same time!

Sound Demos
Sine, 4-notes MP3 (138k)
Triangle, 4-notes MP3 (138k)
Saw, 4-notes MP3 (138k)
Ramp, 4-notes MP3 (138k)
Pulse, 4-notes MP3 (138k)
4 ramps in unison, 4 notes MP3 (138k)
4 Oscillators sin,tri,saw,pulse in unison, 4 notes MP3 (138k), Patch
Sine as LFO to another Osc sweeping pulse width MP3 (138k), Patch