Synthesizers.com Q106 User manual

Q106 Oscillator
Jun 2014
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.
The frequency (pitch) of the oscillator is controlled manually, by voltages
from other modules, and by voltages from controllers such as keyboards.
Both linear and standard 1-volt-per-octave exponential voltage inputs are
provided - each scalable by panel controls.
Five waveforms are available simultaneously - Sine, Triangle, Sawtooth,
Ramp and Pulse. The Pulse waveform is adjustable manually and may be
modulated via external voltage control.
A Hard-Sync input allows synchronization between oscillators.
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.
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.

Q106 Oscillator
Jun 2014
Range Switch
Low=LFO rates Fine frequency
adjustment
+/- 1/2 octave
Waveform outputs
10v p-p
Hard Sync input
Use Saw from
another oscillator
Linear
input adjust
Pulse width
modulation
input
variable
1V/Octave
input adjust
1V/Octave
voltage control
inputs
Manual pulse
width adjust

Q106 Oscillator
Jun 2014
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.
Waveforms

Q106 Oscillator
Jun 2014
Specifications
Panel Size: Dual width 4.25"w x 8.75"h.
Response: 1/V-per-Octave
Frequency Range: .05hz to 20khz
Power: +15V@30ma, -15V@30ma, +5@5ma.
Output Waveforms: Sine, Triangle, Saw, Ramp, Pulse.
Waveform Levels: 10V PP
Sine Waveform THD: 3%
Pulse Waveform Duty Cycle: 5% to 95%
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.
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 oscilla-
tor.
Test Equipment Used (all have recent calibration):
HP 5335a 9 Digit Frequency Counter
Fluke 3330b Voltage Calibrator
Desired Actual % Error
32Hz 32.07hz +0.22
64hz 64.16hz +.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
Please see the website for
additional performance tests.

Jun 2014
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 addi-
tional 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 adjust-
able 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 an-
other 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 am-
plifier (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 synchro-
nize 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 re-
sponse connector or the linear response connector and completely change the waveform. You can see
what’s happening with an oscilloscope. Almost any type of waveform can be produced this way.
1V/Oct Jacks
When J17 is jumpered at 1-2 then the 2 1V/Oct Jacks are independent, when set to 2-3 they are con-
nected to allow daisy-chaining multiple modules to eases patching.
Q106 Oscillator

Jun 2014
PC Board Layout
Q106 Oscillator
Calibration and Testing
1. Apply power for 10 minutes to warm up circuit.
2. Attach a frequency counter to the Sine output.
3. Attach a voltage calibrator to the far left 1V/Octave input.
4. Set the frequency Range knob on the front panel to 32' and the frequency knob to center (0).
Make sure not to bump the frequency knob on the front panel during this procedure.
5. Center the base frequency and high frequency pots.
6. ADJUSTING V/OCTAVE - Critical for tracking accuracy. (This can take about 5 min).
a. Set the calibrator to 0V.
b. Adjust the base frequency trim pot to 32hz exactly. Something like 32.03
c. Set the calibrator to 1.000V.
d. Adjust the V/Octave trim pot to get 64hz. Something like 64.06 (double the previous reading)
* Turning the V/Octave trim pot clockwise will widen the tracking.
* You will have to change the base frequency trim pot to get back to 32hz after each adjustment.
* Switch between 0V and 1.000V and adjust the trim pot to get the two frequencies exactly double.
7. HIGH FREQUENCY ADJUSTMENT
a. Set the voltage calibrator to 7.000V and set the high frequency trim pot for 4096hz
b. Go back and check for 32, 64, 128, 256.....4096, which should be within .2%-.3%
c. 8192 may be off as much as 1% (82hz) and 16384 may be off 3% (492hz).