joranalogue Dual Gated Precision Control Voltage Processor User Guide
- June 7, 2024
- joranalogue
Table of Contents
SELECT 2
DUAL GATED PRECISION CONTROL VOLTAGE PROCESSOR
INTRODUCTION
A ‘Swiss Army knife for your modular system, Select 2 provides two highly accurate gate-controlled voltage processors in 6 HP. These allow you to create, switch, mute, hold, invert, attenuate, offset, add/mix and subtract voltages, from slow control voltages (CVs) up to audio frequencies. Each processor features two signal inputs, with the left input used by default. A gate on the ‘select’ input switches to the right signal input instead. The signal inputs are normalised to the precision +5 V reference (left) and 0 V (right). Following the input section is a hold circuit. A rising edge on the ‘hold’ input freezes the input voltage at that moment until the gate input goes low again. While most sample/track-and-hold modules only manage a few seconds, Select 2’s ‘low droop’ design enables it to store a held voltage accurately for several minutes. The end of the signal path consists of a gated polariser/attenuverter. Using the knob, the voltage at the output can be attenuated and/or inverted: the gain is −1 (inverted) at the minimum setting, 0 at the centre and +1 (unity gain) at the maximum. The polariser can be disabled using the ‘unity’ gate input. This unique ability enables a variety of interesting gate-controlled signal modulations. Dual-colour LEDs show the output voltage of each processor. Finally, if the A output socket is left unused, the signal is mixed together with the B output. This enables signal offsetting, CV mixing, pitch transposing etc.
CONTENTS
In the Select 2 box, you’ll find:
- Product card, stating serial number and production batch.
- 16-to-10-pin Eurorack power cable.
- Mounting hardware: two black M3 x 6 mm hex screws, two black nylon washers and a hex key.
- The Select 2 module itself, in a protective cotton bag.
If any of these items are missing, please contact your dealer or support@joranalogue.com.
CONTROLS & CONNECTIONS
1. POLARISER KNOBS
Each of the identical voltage processors features a knob to control the
polariser. The signal is inverted at the minimum setting, fully attenuated (0
V) at the centre and remains unity gain at maximum.
2. OUTPUT LEDS
These bi-colour LEDs visualise the processor output voltages in real-time:
blue for negative, red for positive.
3. SIGNAL INPUTS
There are two analogue signal inputs for each processor, with the left input
being used by default. For constant voltage generation, simply leave all input
sockets unused: the left signal input is normalised to +5 V.
4. OUTPUTS
Each processor has an accurate, impedance compensated signal output. If
nothing is plugged into the A output socket, its output signal is mixed
together with the B output. This allows you to apply an offset to a signal,
mix two signals etc.
5. HOLD GATE INPUTS
Apply a gate signal to the hold input to ‘freeze’ the input voltage. While the
hold gate is high, any changes in the signal inputs are ignored. When the gate
goes low again, the circuit snaps back to the voltage at the currently
selected input. Each processor can thus function as a track-and-hold for both
CV and audio. However, the exceptionally low leakage rate also allows minutes-
long storage of pitch-accurate CVs. All of Select 2’s gate inputs are uniquely
designed to be driven reliably even from weak, slow, bipolar signals. They
feature Schmitt action, with a +2 V low and +3 V high logic threshold.
6. SELECT GATE INPUTS
This gate input selects between the processor’s signal inputs: if unused or
low, the left signal input is selected. A high gate signal selects the right
input instead. Apart from selecting between two inputs, this gated selector
switch also allows you to create gate-activated constant voltages or to mute
signals.
7. UNITY GATE INPUTS
The unity gate input is used to disable the polariser. When disabled, the
output signal simply remains at unity gain, as if the polariser knob would be
set to the maximum position.
PATCH IDEAS
GATED CONSTANT VOLTAGE GENERATOR
If none of a processor’s signal or gate inputs is used, the +5 V reference
voltage is sent to the polariser. Use the knob to generate a manually variable
voltage between −5 V and +5 V at the polariser’s output. This is useful for
controlling CV inputs without dedicated knobs.
This constant voltage can be disabled (switched to 0 V) using the select gate
input. When the select gate is active, the right signal input is selected,
which is 0 V by default. The output signal can also be switched to +5 V using
the unity gate input, which disables the polariser.
GATED ATTENUATOR/POLARISER AND MUTER
Similar to the gated constant voltage generator, except in this application an
external signal is connected to the left signal input. Now the knob attenuates
and polarizes the signal. Mute it with a select gate, and disable the
polariser using the unity gate input.
RING MODULATOR
Select 2 can be used to create classic ring modulator tones. Set the knob to
the minimum setting and connect your audio-rate carrier and modulator signals
to the left signal and unity gate inputs respectively. The modulator should be
a square or pulse wave for the best result, as this is a logic input. Use the
knob to control the depth of the ring modulator effect.
AUDIO TRACK-AND-HOLD
Another classic synthesiser audio effect is the track-and-hold, creating
digital-sounding ‘downsample’ tones using analogue circuitry. Patch Select 2
like the ring modulator, except the modulator, is sent to the hold input.
While the hold input is high, the carrier signal is ‘frozen’. Once the hold
goes low again, the output snaps to follow the carrier input. Vary the pulse-
width of the modulator to sweep from a subtle effect to full-on sample-and-
hold.
VARIABLE WAVEMORPHER
Connect two different waveshapes from an oscillator (for example, sine and
saw) to the two signal inputs, and the oscillator’s pulse output to the select
gate input. The result is a morphed signal, where each waveshape makes up part
of the total period. By adjusting the oscillator’s pulse-width parameter, the
morphing can be varied.
SEQUENCE SELECTOR
Patch two CV sequences to both signal inputs, and a gate sequence to the
select gate input, all driven from the same clock. Now the gate sequence
selects between both CV sequences: left when low, right when high. Easily
create new hybrid melodies just by changing the gate sequence.
ATTENUATOR/POLARIZER AND OFFSET
Thanks to the mixing feature, both sections can be used together to both
attenuate/polarise and offset a signal. Simply plug your signal into the left
B input. The A knob controls the −5 V to +5 V offset, while the B knob
controls the attenuation and polarisation. This method also allows −10 V to
+10 V constant voltages to be generated from the bottom processor, when all
inputs are unused.
GATE-TO-AUDIO CONVERTER
If you have an audio-rate gate signal (switching between 0 V and +5 V), you
can convert it to a standard zero-centred 10 Vpp (−5 to +5 V) signal using
Select 2. Set one of the knobs to the minimum setting, plug your signal into
the corresponding unity gate input, and leave all other inputs on that section
unused. The output signal is a 10 Vpp square wave, not inverted with respect
to the original gate signal.
SPECIFICATIONS
MODULE FORMAT
Doepfer A-100 ‘Eurorack’ compatible module
3 U, 6 HP, 30 mm deep (inc. power cable)
Milled 2 mm aluminium front panel with nonerasable graphics
MAXIMUM CURRENT DRAW
+12 V: 25 mA
−12 V: 25 mA
POWER PROTECTION
Reverse polarity (MOSFET)
I/O IMPEDANCE
All inputs: 100 kΩ
All outputs: 0 Ω (compensated)
DC VOLTAGE ERROR
0.3 % maximum
BANDWIDTH
25 kHz (−1 dB)
OUTER DIMENSIONS
128.5 x 30 x 43 mm (H x W x D)
MASS
Module: 80g
Including packaging and accessories: 165g
SUPPORT
As all Joranalogue Audio Design products, Select 2 is designed, manufactured
and tested with the highest standards, to provide the performance and
reliability music professionals expect.
In case your module isn’t functioning as it should, make sure to check your
Eurorack power supply and all connections first. If the problem persists,
contact your dealer or send an email to
support@joranalogue.com. Please mention your
serial number, which can be found on the product card or on the module’s rear
side.
REVISION HISTORY
Revision E: no functional changes.
Revision D: initial release.
With compliments to the following fine people,
who helped to make Select 2 a reality!
Ben ‘DivKid’ Wilson Björn Jauss
Boris Uytterhaegen Gregory Delabelle
Jan D’Hooghe Jens Van Daele
Lieven Stockx Sebastiaan Tulkens
Everyone at Wired Electronics
Select 2 User Manual
version 2019-07-15
21 st Century Analogue Synthesis—Made in Belgium
© 2018—2019
info@joranalogue.com
https://joranalogue.com/
References
Read User Manual Online (PDF format)
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