The VCO has a range of about 12 octaves, and produces four waveforms simultaneously: pulse (rectangle), sawtooth, triangle and sine waves.
The VCO's frequency is determined by the position of the range switch, tune and fine tune controls, and the voltage at the two pitch CV inputs, CV 1 and CV 2. Footage (the octave of the fundamental) is set by the Range control, which has seven octave steps.
The Tune control is used for coarse tuning, and the Fine control for fine tuning of the VCO pitch.
The A-111 can be modulated by both exponential and linear FM (frequency modulation).
You can control the pulse width of the square wave either by hand, or by voltage control - Pulse Width Modulation, or PWM for short. The A-111 also has inputs for Hard Sync and Soft Sync.
As the special circuit CEM3340 used in this module is no longer available the module has to be discontinued.
After some questions in the Yahoo Doepfer A-100 Usergroup, Dieter had a bit more info about the new modules:
" Currently we have prototypes of three totally different types of thru-zero VCOs to be in the starting blocks:
A quadrature version with sine/cosine outputs (prefect sine/cosine outputs, much better than sine waveshapers): A-110-4
A triangle core version (with waveshapers for saw, rectangle and sine): A-110-3
A trapezoid core version (with waveshapers, based on Don Tillman's idea and with his permission): A-110-5 (?)
The A-110-4 will be manufactured early in 2015. We still have some problems with the A-110-3 and A-110-5 because the prototypes produced so far behave a bit different and we still have to find out the reason and fix the problems.
A-110-2 (final version), A-110-3 and A-110-4 will be introduced at NAMM in January (as well as A-147-2, A-138u, A-160-2, final versions of A-101-6, A-190-5 and A-157, and maybe some more). "
I do have to dig a bit deeper into this module before i completely understand it, but here is the text from the Doepfer website, where they will soon have audio examples and oscilloscope views available...
Doepfer A-110-4
Thru Zero Quadrature VCO
" The term "quadrature" means in this connection that the oscillator outputs sine and cosine waveforms simultaneously.
The term "Thru-Zero" means that even "negative" frequencies are generated.
This can be a bit of a misleading term as negative frequencies do not really exist.
"Negative" means in this connection simply that the sine/cosine waves will stop when the linear control voltage reaches 0V and continue with the opposite direction as the linear control voltage becomes negative and vice versa.
The module has two control sections: linear and a exponential.
The exponential section consists of the XTune control, the 1V/Oct input and the XFM input with the corresponding attenuator XFM.
The exponential control voltage is the sum of these three voltages.
The linear section consists of the LTune control and the LFM input with the corresponding attenuator LFM.
The linear control voltage is the sum of these two voltages.
A dual color LED is used to display the polarity of the linear control voltage (green = positive, red = negative).
The resultion pitch of the sine/cosine outputs is determined by the resulting control voltages of both sections. The linear section is used to control the pitch in a linear manner.
When the LTune control (LTune means Linear Tune) is fully CW the module works like a normal Quadrature VCO (e.g. like the A-143-9) and the LED lights green.
The pitch is then controlled by the exponential section with the manual Tune control and the exponential frequency control inputs 1V/Oct and XFM. 1V/Oct is used to control the pitch by a 1V/Oct CV source (e.g. sequencer or Midi/USB-to-CV interface).
XFM is used to apply an exponential frequency modulation with adjustable depth (e.g. from an LFO or another VCO).
As the LTune control is turned counterclockwise starting from the fully CW position the frequency is lowered in a linear manner until the sine/cosine waves stop near the center position of LTune (provided that no LFM signal is present).
As the LTune control is moved from the center towards the CCW position the waves start again but into reverse direction and the LED turns red.
When the fully CCW position of LTune is reached the module works again like a normal Quadrature VCO.
But much more exciting is the usage of the LFM input to modify the linear control voltage by an external control voltage (typically another VCO).
Linear modulation by another oscillator using the thru zero feature generates audio spectra than cannot be obtained from an oscillator without the thru zero function.
The reason is that a "normal" VCO will simply stop as the linear control voltage becomes zero or negative.
But a thru zero VCO will start again with "negative" frequencies as the the linear control voltage becomes negative.
The main advantage of the A-110-4 compared to other Thru Zero VCOs is that the design used a sine/cosine core. The sine/cosine waves are not derived from other waveforms (e.g. sawtooth or triangle) by means of waveshaping.
Rather the sine and cosine waves are the core of the VCO which results in very pure waves with a minimum of distortion and overtones."
The A-110-4 is planned for early 2015, price ~ Euro 120.00
rezfilter made a nice video demonstrating the features of the 38HP wide Medic Modules Cranial Saw.
The Cranial Saw is a dual VCO
with Glide, Sync, Sub Oscillator, Pulse Width Modulation, Mixer and Cross Modulator.
" It features two discrete component VCOs based on early 1970s circuits so they sound very vintage and are full of character.
The dual VCO performs best in mid to low range, and combined with the Sub-Osc, produces huge, powerful sounds. The main pitch CV input goes through a Glide / portamento circuit. There are modulation CV inputs with attenuators. Also, VCO2 has its own CV Mod input. Each VCO has a Pulse Width slider and PWM CV input sockets. The VCOs also have Sync.
Cross modulation is possible by taking the output of say VCO1 and patching this to VCO2’s Mod CV input. The built in mixer allows the two VCOs and the Sub-Osc to be mixed via their own attenuators.
The mixer has its own audio output of course, but the VCOs and Sub-Osc also have pre-mixer, fixed level individual outputs. The two VCOs each can be switched between Saw or Square waveforms.
VCO1 can be set to ‘Freerun’.
This means it will not track the incoming pitch CV. VCO1 can be disconnected from the Glide circuit. Features such as Freerun, and the Glide disconnect of VCO1, as well as individual Mod CV for VCO2, allow a great range of sounds and weird effects to be produced when cross mod is patched, or Sync used.
A lot of thought has been put into all this. Please take a look at the videos on Analogue Solutions web site and YouTube channel for examples. The idea is to allow production of a wide range of VCO sound effects with the minimum amount of patched, though, of course, patching can be done. All sliders incorporate a LED in their shafts. The Tune slider will flash in accordance to the pitch of VCO1."
" The Cranial Saw is an advanced VCO / SUB eurorack module with glide, featuring a whole range of flexible modulation possibilities to appease even the most demanding musicians and euro enthusiasts."
Electronic Music Analog Synthesizer shop Les Indes from Berlin uploaded this long (almost 13 minutes) demo to YouTube.
The video mainly shows off the A-111 VCO and the (discontinued) Doepfer A-121 Multimode Filter...
Video: DOEPFER A-100 Modular System w Legacy Filter
" Featuring: High End VCO A-111 (running out of production), Multimode Filter A-121 (discontinued)"
Always nice, those unexpected new module announcements.
Doepfer announced the A-110-2 on their site recently, a low cost VCO, similar to A-110, but sawtooth, triangle and rectangle with PWM only.
The module will have a 3-position octave switch (instead of the rotary switch of A-110), Soft and Hard Sync inputs, linear FM input.
This should all fit on a 8 HP front panel, the 'original' A-110 is 10 HP wide.
The module is planned for fall 2014 and will be priced at around Euro 110.00
(The A-110 costs 140 Euro's)
Power consumption:
- 150 mA +12V
- 150 mA -12V
- 50 mm Depth
Update Oktober 13, 2014: Dieter Doepfer in the A-100 Usergroup "...the A-110-2 is planned still for this year. I hope the first units will be available end of November.
An interesting topic popped up on the A-100 Facebook Group recently;
" How do you guys trigger your analogue synths sounds on live gigs? "
I do change my setup from time to time, but i do have some kind of basic setup for my live-sets and jams.
I have a total of 5 VCO's in my A-100 system, and i try hard to get the most out of it every time i play.
Elektron SPS-1 Machinedrum
At the heart of my setup there is a drum-section, consisting of a Roland R-8 and an Elektron SPS-1 Machinedrum. The Electron is a perfect machine with plenty of electronic drum sounds, i use the R-8 for the more 'organic' drumsounds.
MSY-2 MIDI-to-SYNC Converter
Synchronizing over MIDI is controlled by the R-8, through the Machinedrum and through a Doepfer MSY-2 MIDI-to-SYNC converter straight into the MAQ 16/3 Sequencer.
The MSY-2 is used to keep my TB-303 basslines in sync with the rest.
I also use the CV and Gate outputs from the TB, i get back on this later.
The MAQ 16/3 is Doepfer's MIDI Analog Sequencer.
It has 3 sequencer rows of 16 steps with Gate and CV outputs, i mainly use the top 2 rows for programming loops and basslines. From the MAQ 16/3 it all turns analog and goes right into my A-100 system.
MAQ 16/3 main controls
Row 1: main row, usually a 16 step pattern;
The first row's CV goes through an A-180 multiple into two separate A-110 VCO's (with sometimes a slight de-tuning involved )
I often turn one of the VCO's 3 or 4 octaves up and send one of its output waves through an A-115 Audio Divider to add some extra (sub) bass.
These layers all mixed together with an A-138 mixer can be send from here to any other kind of filter or effect module, ending in an A-130 VCA somewhere.
The first row's Gate signal goes into input 1 of my A-143-2 Quad ADSR, that contains 4 independent ADSR-type envelope generators.
Gate input 1 is automatically connected to the switching contacts of the Gate input sockets 2, so from that single input i can retrieve 2 different envelopes.
One of them is sent to a VCA, the other one often goes to a CV 2 input of one of my filters.
That is basically my first (sequenced) A-100 Audio-source #1.
Row 2: Usually 6, but sometimes even 3, 8 or 12 steps long;
The CV signal from the MAQ's second row goes straight into my third VCO.
One or multiple waveforms can be sent from there and used for various different purposes, filters etc... coming together in A-130 VCA nr 2
Gate 2 goes into the third input channel of the Quad ADSR, i split up this with another multiple so i have 4 identical envelopes for use in the rest of my system. One of them goes to VCA nr. 2
So that's my second (sequenced) A-100 Audio-source #2.
VCO 4 is controlled by the CV coming from my (synced) TB-303.
The 303's gate signal triggers an ADSR for another A-130 VCA envelope.
I can send this audio-signal through all sorts of modules, resulting in A-100 audio-source #3
My 5th VCO ( and my only A-111 High End VCO ) is used for my solo's.
With an A-182-1 Switched Multiples i can easily switch between my MIDI masterkeyboard or my A-198 Ribbon Controller.
More info on this in detail HERE.
The Ribbon Controller CV goes into my A-156 Quantizer and an A-170 Slew Limiter for easier playing and a nice glide effect, as blogged HERE.
The Gate signal from my MAQ's row 3 (max. 16 steps or pauses) is sent to the 4th input of the Quad ADSR.
I like using this programmed (almost arpeggio-like) envelope to open a filter or amplifier with this, watch the video to see what i mean by that.
I have plenty options to do whatever i want with the wave-forms from this 5th VCO, but I like to keep the sawtooth wave for the A-129 Vocoder.
I guess that makes up audiosources #4 (vocoder) and #5 ( the VCO ) then...
What i did not mention here are the various other mixers and multiples used, the added noise, filters and LFO etcetera, but i hope you understand this is just the basic configuration of my A-100.
Video: Just me... and the Music take 1, an older jam by myself (from YouTube)
" Live Electronic Jam by NetPierre.NL feat. Doepfer A100 + Ribbon Controller, TB303, Machinedrum and effects, no post-production, and sadly no compession ) "
Interesting sound-effects can be obtained by the synchronising of (multiple) oscillators.
In a typical setup, one oscillator (master) restarts the cycle-period of the other one (slave) , what results in equal base frequencies on both oscillators. This is called Hard Sync.
The result is an irregular waveform with it's own harmonic spectrum, completely different from 'standard' waveforms
Soft Sync is a more general name for all kinds of oscillator synchronisation. This form is very similar to Hard Sync, but here the slave oscillator is forced to reset to zero with every cycle of the master regardless of position or direction of the slave waveform, which often generates asymmetrical shapes.
In Soft Sync, rather than resetting to zero, the wave is inverted; its direction is reversed. Further variations to the sound can be made by comparing the sounds with different comparison tresholds. For more info see the Wikipedia page on Oscillator Synchronisation Soft Sync sounds smoother and distinctly different from hard-sync.
It is difficult to replicate this effect on digital synths, due to aliasing problems.
Soft Sync-like effects can also be created with other modules, for example a phaser or a Phase Locked Loop (PLL) Module.
The engines or hearts of all modular synthesizers are definetely the VCO's. As main sound source for your patches it seems you never have enough of them.
I own 5 VCO's at the moment, One A-111 High End VCO plus four A-110 Standard VCO's. Ideal for stacking layers of waveforms to make extra- fat sounds, and also very useable for multiple A-100 melodylines
The A-111 is the one i use most because of its extended possibilities.
This VCO has an extended frequency range, improved waveforms, FM and Soft Sync inputs plus an extra fine-tune-controller. Ideal for controllerfreaks like me.
It produces sine, triangle, pulse and sawtooth waveforms, which are all derived from the triangle oscillator, what does make it hard to produce perfect sine-waves ( but a little better as the A-110's sine wave )
One of the best things is that all 4 waveforms are all simultanously available at the outputs for your mixing pleasure.
The much cheaper A-110 has less controls and is based on a sawtooth oscillator. All outcoming waveforms of this module are derived from this sawtooth by internal waveform converters. This module also generates sinewaves that are not completely perfect, but to 'normal' ears this is hardly audible
I never noticed, and i guess most of us don't care and never noticed the imperfect-ness of the sinewaves of both modules.
Even on an oscilloscope it is hardly visible that the sinewaves are nothing more than rounded sawtooth-waves.
For a perfect sine wave Doepfer recommends the A-143-9 Quadrature LFO/VCO, another interesting module, that i will highlight in a future blogpost.
Note: As the special circuit CEM3340 used in the A-111 High End VCO module is no longer available the module has to be discontinued. Sales at Doepfer while stocks last !
