Thursday, November 1, 2012

The White Dwarf hybrid modular synthesizer

Here's the latest iteration of my Eurorack modular, named The White Dwarf :

During the last months, my White Dwarf has undergone a quite significant downsizing.
The complete system (including the FriFri Deluxe patch matrix) once culminated at a (too) massive 1176hp.

I've now brought back the hp count to a mere 252, parting with some modules that didn't get much use and thus redefined the instrument, focussing on simplicity, efficiency, ergonomics and playability, limiting functionality to the essential. 
No more dedicated sequencing modules as I prefer to articulate my pieces using modulators only (mainly envelopes, LFOs and random CV sources).
Analogue oscillators (Plan B M15, Analogue Systems RS95e (x3) and Pittsburgh Modular Generator) were replaced by digital audio sources and processors. Still, I'm planning to extend the actual system with some complex analogue oscillators (considering Make Noise's DPO, Intellijel's Rubicon, SDIY, ...) in a not too distant future.

Here's a shot of a friend of mine playing The White Dwarf :

And here's a close-up :

Top row :
- Synthesis Technology E560 Deflector Shield
- Synthesis Technology E350 Morphing Terrarium
- SDIY expander for two E350s
- Synthesis Technology E350 Morphing Terrarium
- Synthesis Technology E340 Cloud Generator
- Synthesis Technology E580 Resampling Mini Delay

Central row :
- Make Noise/Wiard Wogglebug
- STG Soundlabs Post-Lawsuit Filter
- Doepfer A-156 Dual Quantizer
- Make Noise Maths
- STG Soundlabs Sea Devil Filter
- Synthesis Technology E355 Morphing Dual LFO

Bottom row :
- Plan B M9 Mixer/Attenuator
- Plan B M10 Polyphonic Envelope
- Oakley Sound Systems Classic Ring Mod
- Pittsburgh Modular Analog Delay
- Pittsburgh Modular Dual Index
- Plan B M10 Polyphonic Envelope
- Plan B M9 Mixer/Attenuator

This selection of modules provides a good balance between audio sources, processors and modulators to form a coherent, self contained, flexible, versatile and powerful yet compact modular instrument with a strong and unique sonic footprint. Like this, it is perfectly matching my own personal needs, production techniques, patching methods and it is delivering the sonic aesthetics I'm currently after. 

Module layout is optimized for visual symmetry, maximum ease of use and comfortable patching.
Visual unity and coherence is enhanced by reknobbing some modules.
Three types of knobs were selected :
Volcano knob VC-MINI 

As mentioned earlier, this 9U synth is to be further extended with another 3U for a total of 12U.
Once the last 3U will be filled up, I'll make a nice portable cab for the system so that I can easily take it on the road for performances. Maybe at a later stage I'll add some sort of skiff with controllers and performance tools...

Stay tuned !

Saturday, October 6, 2012

The Micro Mammoth

It is obvious that my main 5U system, the Baby Mammoth, is sedentary by nature, designed to be in the studio and remain there.
As I occasionally perform outside my little cocoon, I begun to think about a portable solution to take a selection of Hordijk modules on the road. I wanted something elegant, compact, ergonomic and comfortable to work with.

So, I designed this little cabinet, perhaps the world's first DIY portable 5U skiff with detachable lid :

It's made of beautiful European walnut and coated with natural, clear, outdoor varnish.
I had it cut and assembled at a local wood workshop, because I don't have the tools and the space to work with the kind of precision I had in mind. I did the sanding, coating and mounted the hardware.
There are strips of felt in between the lid and the base to protect the wood and to prevent dust or moisture to enter the cab when it is closed.

I wanted the modules to be mounted at an angle, not straight up or flat, so that the instrument can be played standing or seated in an equally comfortable and ergonomic way :

I incorporated an IEC connector with a power-on switch and a fuse :

Inside is the power supply and the power distribution board :

Ok, so we can fill her up now :

The cab is designed to hold up to 8 single Hordijk modules (equivalent to 16MU wide), and for this particular selection I chose to integrate the Mini Matrix / Node Processor combo as the hart of the system.

From left to right :
Triple LF-VCO
Mini Matrix / Node Processor
Dual Env
Dual Phaser
Dual Fader

I thought this selection to have the right balance between audio sources, CV sources and processors to be able to produce interesting enough sounds to perform solo improvisations.
For this time, the Dual Phaser was prefered over the Triple Input Filter for various reasons, but this can easily be changed.

I deliberately chose to have the cabinet set up in one single row because of the grid layout of the Rob Hordijk modules, like that of MOTM modules, with all jacks at the bottom of the modules. This way, all modules can be fully patched up without having patch cords running all over the controls and thus freeing access to those very sensitive knobs.

The lid can be left attached to the base and thus being used to hold patchcords during performance. Also, the synth can be left patched up with the lid closed.

Ready to Roll

Friday, October 5, 2012

Baby Mammoth is now fully mature

My 5U modular synthesizer system, named the Baby Mammoth, is now up to completion :

The system is dual brand, consisting of 2 rows of 12MU each of Mos-Lab modules (faithful reproductions of the original Moog modules) :

2x CP-10 mixer
1x 992 controls to oscillator
1x 921-A oscillator driver
3x 921-B oscillator
2x 995 attenuators
1x 911 envelope generator
2x 902 voltage controlled amplifier
1x 904-A voltage controlled low pass filter
1x 904-B voltage controlled high pass filter
1x 904-C filter coupler
2x 905 reverberation unit

The bottom two rows are occupied by Original Rob Hordijk Design modules :

1x Dual phaser
1x Triple Input Filter
1x Dual Fader
1x Rungler
1x Triple LF-VCO
2x Dual Env
1x Mini Matrix / Node Processor combo

Last weekend I had Rob Hordijk coming over to my place to deliver the latest additions to the system, the two Dual Env, the third VCO HRM and the Dual Phaser :

The Dual Env, as it's name suggests, consits of two voltage controlable envelope generators.
Both share the same Gate input.
The first one is of the ADBDR type (Attack, Decay I, Break, Decay II, Release).
Each stage has its own control voltage input (unattenuated), except for the Break parameter.
The second envelope is a simple voltage controlled Decay with direct output and polarized output.
In addition, there is a S&H circuit that can be used indepently .
When self-patched or cross-patched with a Triple LF-VCO, the Dual Env proves to be very effective at creating complex, polyrhythmic modulations.
Here's the block diagram and panel layout of the Dual Env:

And here's a more detailed description of the module :

"The Dual Envelope module (DUAL ENV) is a fully voltage controlled envelope generator specifically designed to be used with sequenced music. There are two different types of envelopes available, one is a four stage (attack, decay1, break level, decay2, release) envelope and the second is a one stage envelope (decay only). Both envelope generators share the same gate input, meaning that they can not be triggered separately. Triggering treshold is at roughly 100mV above ground and also accepts e.g. triangle waves. The ADBDR envelope is primarily intended to be used for volume envelopes. When the decay2 knob on the first envelope generator is fully open the decay2 acts like the sustain that you find on most of the traditional envelope generators. In this case the break control will act like the sustain level. There are CV inputs for the attack, decay1, decay2 and release rates. The CV for the attack is inversed, so increasing the CV level will shorten the attack time while increasing the decay times for the decay1, decay2 and release. This means that when e.g. the key velocity voltage is used a higher velocity will shorten the attack and increase the other decay times. Rate settings can be from really snappy to pretty slow. Care was taken that you still have good control over the rates when in the snappy range. The second envelope generator is intended as a modulation envelope generator to e.g. sweep a filter or control the harmonic waveshaping of an OSC HRM module. It has an extra output that is controlled by a bipolar mix knob that can invert the envelope shape and also gives some extra overall ‘sink’ or ‘lift’ when the output level is increased. Rate can be set from a glitch to about a minute. When modulating decay times with control voltages it is good advise to keep the voltage fixed while the envelope is developing. E.g. trying to modulate the decay time with an audio rate signal does in general not produce sensible results. A S&H is integrated into the module to sample the decaytime modulation input signal for the second envelope generator on every new gate trigger. This way the modulation amount will stay fixed until the module is triggered again by a new gate pulse. The sampled signal is also brought out on a connector, so it can be routed to a CV input on the first ADBDR envelope generator. Or be used in any other S&H application. The ADBDR envelope is designed in a way that is hás to finish its attack phase to reach its peak level before it can be retriggered. When used for sequencing this allows for complex envelope shapes that give interesting rhythmic effects, but when used for keyboard play it might feel a bit strange to play the module with long attack times and fast play. Note that there are no attenuator knobs to set the amount of modulation for the ADBDR envelope CV inputs, these inputs are at full sensitivity. They can be connected directly to e.g. the velocity CV or CC# CV outputs of a MIDItoCV converter, but when modulated from other sources one might need an extra CV mixer module to set the modulation levels properly."

The Dual Phaser is more of a complex multiple filter system than your average, bread & butter phaser. The two phase shifters are independent and can be used separately or can be used in parallel or series. The sound is lush, precise, punchy, crispy, deep and organic. It delivers wonderfully at the classic sweep on the pad/noise patches, but also gives more unusual vocal, liquid and percussive sounds when patched in a less conventional way.

Here's a more detailed description, along with the panel layout :

"The internal CV voltage scale is 1V/Oct. Each phaser has a reasonably accurate one volt per octave direct control input that can track the keyboard voltage. Normalization is used, routing the V/Oct input signal of phaser1 into phaser2 when the phaser2 V/Oct input is left unplugged. Total control range is about 18 octaves. The Frq knob goes over the top 9 octaves of this range. Through the V/Oct and Modulation inputs you can go deeper, but you get into the LFO range and audible phasing effects would disappear. It is however possible to use the phasing effect on LFO control signals in the 1Hz to 10Hz range by supplying the V/Oct with e.g. a fixed -5V control signal, which can create quite interesting LFO effects on e.g. drones. All inputs and outputs are DC coupled, so CV signals can pass the module equally well as audio signals. Only the internal resonance is AC coupled, so resonance drops off below roughly 10Hz. Additionally each phaser has a modulation input, also at 1V/Oct when the mode is set to sweep. When the mode is set to spread it behaves like the modulation sensitivity is halved, also when it is in half mode where only half of the poles in each phaser are modulated by this input. These inputs are not normalized, in fact if no plug is connected the modulation level knobs receive a fixed voltage so a manual spread value can be set. Audio input is maximum 12V peak/peak before clipping occurs and there is 6dB attenuation from input to output to enable resonance peaks without clipping. Audio routing is as follows: If a jack is connected to input1, and if input2 is unconnected, then the audio will route into both phasers. In this mode you can use the two phaser outputs as a stereo signal. Connecting a jack to input2 will override this internal input1->input2 connection and separate both phasers. If audio is routed into input1 and if input2 is left unconnected, and if a jack is connected into ónly output2, then the two phasers are automatically set to "inverse parallel" mode. Meaning that if both phasers are set to exactly the same knob settings the phaser outputs would be in exact reverse phase and thus result in almost silence. If audio is routed into input1, and if output1 is connected with a short cable to input2, and if output2 is taken as the overall output, the two phasers are in series and thus result in one 16-pole phaser. To summarize: you can use the phasers fully separated, parallel with two (stereo) outputs on one input signal, parallel with mono output but with one phaser in reversed phase before the mixing of the outputs of the phasers take place on output2, or in series. All this is accomplished by the internal switches in the connectors and only depends on which inputs and outputs have a plug."

Another very interesting module, which I haven't covered before, is the Mini Matrix / Node Processor combo.

This combo can be associated to a Triple LF-VCO, a Dual Env or a Rungler in a triple panel.
The Mini Matrix is a buffered 6 inputs and 4 outputs routing and mixing system using TRS jacks.
Each row of the matrix can be used as a simple 4-way buffered multi when inserting mono jacks in the row's nodes.
Multiple inputs can be routed/mixed to one output using TRS jacks (with shorted tip-ring, or with a resistor between tip and ring for attenuation). The matrix comes with some ready-made shorting jacks with a female banana socket to interface with other systems using banana plugs.

Here's a more detailed description of the matrix system :

"The Active Matrix module is a fully buffered six by four matrix where any one of six input signals (rows) can be added to any one of four outputs (columns). By using ¼-inch tip-ring-sleeve insert jacks for the matrix nodes (equal to stereo jacks) a whole range of applications become possible. First the row input signal is buffered and then routed to the tips of the nodes in that row. The ring signals of the nodes are basically summing inputs and summed to the final output signals at the ends of the columns. By connecting a stereo jack where the tip and the ring are connected directly together, a connection with unity gain is made from a row input to a column output. If the tip-ring connection in the jack goes through a resistor an additional attenuation can be accomplished. E.g. a 30k resistor will attenuate by 6dB and a 91k resistor by 12dB. When a stereo audio cable is soldered to a jack plug and on the other side of the cable a potentiometer is attached, the potentiometer will act like a pot on the node, enabling to set the mix level by the pot. Basically each node is an insert, just like the inserts on a mixing desk. And can thus be used in the same way. So, using a jack with a pot means to ‘insert’ the pot into the signal path. This means that you can insert any other external device in the signal path by using an insert cable with a stereo jack on one side and two mono jacks on the other, provided signal levels match of course (e.g. 5V pp oscillator output signals will severely overload line level inputs on e.g. a digital effects rack or the guitar input of a stompbox). One could also connect a resistive sensor like a light dependent resistor (LDR) to a jack and make the node light sensitive. Each row also acts like a multiple. When a mono jack is connected into a node it will pick up the row input signal from the tip. But the ring input is now short circuited to the ground through the sleeve of the mono jack and will so disable any input from this particular node to the column output. This will not interfere with any other nodes in the same row or column, because of the full buffering of both the row inputs and column outputs. So, any node that is not used to route a signal to a column output can be used as a multiple output. Meaning that the matrix is also six multiples with one buffered input and four buffered outputs on each multiple."

Now for the Node Processor :
It consists of a quantizer with independant range and scale control,  a Gain pot that provides up to 20dB boost, a bi-polar offset generator (-5V -> +5V), two voltage controlled bi-polar VCAs and two audio tapers. In addition to the Node Processor I/O jacks, there's a Transpose input.
Node Processor functions are simply inserted into the nodes of the matrix by using stereo (TRS) patch cables.

The Mini Matrix / Node Processor combo is a crucial addition to any small to medium sized system with little or no dedicated utilities and/or mixers.

Here you can download the manual : Working with the Mini Matrix and Node Processor
All these together add up to form a powerful, flexible and versatile yet compact modular system with bags of character, attitude and loads of creative potential ... Thank you Mr. Hordijk !

Tuesday, August 7, 2012

Synthé modulaire 2012 - free compilation

Artwork by ReNédesFlammes

The French speaking forum on modular synthesis,  Synthé modulaire , is proud to present the second annual compilation of pieces produced by active members of the forum.
For this year's compilation, the name of the game was "collaboration", in opposition to last year's solo works only.
This is to expand each participant's approach to modular synthesis by putting together his own and other people's methods, to explore new creational paths and bring together people with sometimes different mindsets for a common project. We wanted to develop plurality over individuality.
Strong artistic personalities sometimes clash but also sometimes can create beautiful things in joining forces for an even stronger output.

Mainly two different approaches were used for these creations.

One method is physical, very intuitive, where the performers meet physically for instantaneous, spontaneous and common output. Working towards that "magical" moment when it all fits together, generating happy accidents whilst freely improvising, without any frame or prepared basis. This can be hazardous when in a live performance context but here it was done in a familiar environment with only the other party as audience. Improvisation on modular synthesizers is a very demanding affair in terms of concentration (as it is the case with all types of instruments) and discipline, especially when there's more than one player... One has to pay attention to what he's doing but also needs to listen very carefully to what the other(s) is/are doing. It helps when the players know each-other well but it can be interesting to discover new or unknown aspects in each player's output.

The other method is virtual and differed in the sense that individual tracks are exchanged and that the pieces are built up gradually, layer by layer. Each one providing material that can be reworked and/or complemented by the other. This way of working obviously relies less on immediacy but is in no way less valid. Time is taken to refine details and to explore all available options. Validation of the material by all implied parties is essential. Results of this methodology are obviously more controlled, perhaps but not necessarily less intuitive and also very interesting. This production technique is more natural to artists that are geographically set apart or have differing schedules.

All in all, I think the pieces for this year's compilation are a little "wilder", more loose and more adventurous than the ones on the previous set. I guess this is inherent to the creational processes described earlier and in that respect I think the initial goals are reached.

The pieces on this compilation are not copyrighted and are free for you to enjoy. Please don't make any commercial use of these pieces without explicit consent of their creators.

No normalization or mastering has been applied to this compilation, so there are some significant differences in average output levels of the individual tracks.

You can download or listen to it on Bandcamp, here

Track listing :
1. Zeitdehner Vs ReNédesFlammes : Nonexistent colours surrounding the subject
2. Yohda Vs MechaSeb : Under the lightning wall
3. Zeitdehner Vs Phisynth : A machine, made entirely from ice, still detecting the remnants of galaxies
4. Phisynth Vs Trap&Zoid : Smells like a Burned Pizzeria
5. Trap&Zoid Vs RenéDesFlammes : Les Zombelges
6. Zeitdehner Vs Trap&Zoid : Sponge
7. Protofrangiste Vs Fréquence absurde : ProtoZap
8. [Djo] Vs MechaSeb : Recitify the parallax 

Tuesday, June 5, 2012

Synthé modulaire 2011 - free compilation back online

Well, here it is again !

After the demise of Megaupload, the 2011 free compilation produced by members of the French speaking  forum "Synthé modulaire" is back online, free for you to download and enjoy.

Click here to get it now on our Bandcamp page !

Watch these pages as the new 2012 compilation is coming up shortly... full of exciting collaborations and fresh modular sounds !

Thursday, May 17, 2012

Zeitdehner goes BIGGER

When I first thought of my Mos-Lab system, which is quite basic, the intention was to expand its capabilities with the Eurorack system I have and to afterwards complete it with some other 5U modules to obtain a self contained, cohesive, versatile and powerful system. The problem with 5U is that if you want such a versatile and powerful system you easily end up with a huge system, at least with Mos-Lab/ COTK/Dotcom type of Moog clones, just because of the basic nature of the modules... the one (huge) module = one (simple) function syndrome.
Whilst remaining in the MU format, I went looking for modules with much higher functional density and I found some interesting options in Oakley or SDIY, but still, I wanted something else, with a different design philosophy and overall character. That's exactly what I found with the Original Rob Hordijk Designs modules.

So, I settled for a six module combination to start with : a Rungler, a Triple LF-VCO, two OSC HRM, a Triple Input Filter and a Dual Fader. This little set of modules is already very powerful all by itself and contains no less than 7 VCOs, 3 VCFs and 5 VCAs (without counting the numerous CV controls with attenuators) !
Later on I will add another row of Hordijk modules to eventually get an instrument consisting of two rows of 12 MU each of Mos-Lab modules and two rows of 12 MU each of Hordijk modules. This is still quite "reasonable" in terms of size and cost.
This is how the mixed system looks for now, in its home made wooden cab :

The Baby Mammoth modular synthesizer

Before I get to single module descriptions, I would like to share some insight to the philosophy behind Rob's designs. In the process of designing a module, the first constrain is that of the format of the module. For that matter Rob has settled for two units wide MU (Moog Unit) panels. He then sees what maximum functionality can be fit into that finite three dimensional space, i.e. one can only fit that much components onto x square centimeter of PCB, and one can only fit 8 potentiometers and 10 jack connectors (maybe a very few leds and a switch...) while still retaining comfortable ergonomics with clear and logical control layout. This space equation is the main driver behind the engineering choices that have to be made, i.e. can I have voltage control with attenuation over that parameter or not, or would another feature be more useful or more interesting. No guesswork here, it's all about pure engineering skills Rob has developed over many many years working in the electronics industry. Every single feature is thought out carefully, as every single electro mechanical part and component is carefully selected for maximum performance and reliability.
Also notable is the fact Rob has total control over the whole conception and building process. He makes his own PCBs, he stuffs and wires them manually, he cuts and drills his own panels, labeling of the panels is done in house as well as assembly,  trimming and calibration of the finished modules. He does it all by himself ... well, almost, as he has the precious help of his friend and associate Richard. Impressive ! Even more impressive are the resulting qualities of the modules. We all know perfection does not exist, but Rob's modules are getting damn close to that ! Rob puts all his heart, his knowledge, his experience and his skills in his designs. Everything is relevant, every feature is useful and will be used, no flashy, trendy bells & whistles, no useless space filling or price boosting gadgets ... just wonderfully crafted tools with huge creative potential, that perfectly fit his conception of an analogue modular synthesizer system.

Rob, just like Seb from Mos-Lab, builds on demand, no stocking items... with that difference that Rob works fast : delivery of my modules was just about a month and a half away from the moment I confirmed my order.
I personally went to The Hague to pick up the modules at Rob's workshop. This gave me the opportunity to meet him, to learn about his modules as a system, to discuss possible evolutions of the system (he's developing some multi panels, integrating 3 individual modules with some normalizations)  and to discuss analogue modular synthesis in general. In short, I had a great time.
Even more so now that I'm enjoying working with his modules.

Every single module is packed with some clever features, some quite unique. This makes them obviously more complex, with a steeper learning curve  than the average and it takes many many hours of practice to get the full grasp, to understand fully the logic behind certain functions, even for a "seasoned" amateur like myself. It's all about trial and error, happy accidents due to the lack of user manuals and the scarce information being available. Fortunately, Rob is always happy to provide detailed explanations and flow charts. Also, some general information can be found over here : Rob Hordijk Designs Wiki page

The Rungler :

This is a special circuit that is based on two oscillators combined with a shift register. These two wide range oscillators (not compliant to the 1V/Oct standard response) can cross-modulate and/or can be modulated by external signals. Oscillator A produces a Sine wave and provides clocking for the shift register. Oscillator B produces a Triangle wave and provides the material for the shift register. A special Fluctuation modulation signal derived from oscillator B provides combined AM and FM to oscillator A and can be replaced by an external signal. Oscillators A & B are available as direct outputs. The output of the shift register can be applied to oscillator A in Stepped, Smoothed and Pulsed modes simultaneously. These Stepped, Smoothed and Pulsed signals are also available as direct outputs. Clock In & Out makes syncing to other modules possible.
The Rungler has different operational modes that can be selected with a Switch. This module is a unique source of audio and modulation signals, that produces unusual, unpredictable, organic, chaotic or subtly shifting noise, tones, melodic and rhythmic patterns. A microcosmic source of infinitely varying automatic electronic music.

Here's a video of Rob explaining the Rungler module:

The Triple LF-VCO

This module sports three independent low frequency voltage controlled oscillators that can also be synced and cross-modulate.

LF-VCO A provides a Sine wave similar to that of VCO A of the Rungler. It has a wide frequency range going from quite slow to well into the audio frequency band, so it can be used as a sound source as well as a modulator. This LFO is tied internally to LF-VCO C, the latter will modulate the former in FM and in combined FM-AM with the Fluct control (similar to that found on the Rungler). LF-VCO A can  also modulate the frequency of LF-VCO C for cross-modulation. Naturally, that normalization can be replaced by external modulation signals when inserting cables in the respective CV inputs.

LF-VCO B produces Pulse and Triangle/Saw/Ramp waves with variable wave shape which are simultaneously available as direct outputs. The wave shaping is set manually. This one has its frequency range set lower than that of LF-VCO A.
The frequency of LF-VCO B can be modulated internally by LF-VCO C or by an external signal.

LF-VCO C produces Triangle waves in a frequency range set similar to that of LF-VCO B but lower, for really slow oscillations. Next to the normal Triangle direct output, there's also an inverted Triangle direct output.

Three LEDs give visual feedback of the activity of the three LFOs

The Triple LF-VCO has three operating modes, selectable with a switch :

1° MODE : the three LFOs are free running
2° SYNC : LF-VCO B is synced to LF-VCO C or to an external signal
3° HALT : LF-VCO B oscillates at a frequency set by its Rate control during the Rise of the Triangle wave of LF-VCO C and will "freeze" during the Fall of the Triangle wave of LF-VCO C. LF-VCO B will restart with the next cycle of LF-VCO C. When "frozen", LF-VCO B will output a fixed, momentary voltage.

A little illustration of the Halt function :

And the Master himself explaining this module :


This is a fully featured, wide range, voltage controlled oscillator with simultaneous dynamic control over pitch, timbre (harmonic content) and amplitude ! The core is Sine & Cosine based.
It has a 1V/Oct control input, duplicated on the Chain Out connector to be able to distribute the same pitch control signal to several oscillators, and an attenuated frequency control input.
There's a built in VCA with manual initial gain control and an attenuated CV input.
VCA output and direct oscillator output (Full out) are doubled for convenient patching to two destinations (i.e. to have two separate signal paths sourcing from one oscillator).
Dynamic wave shaping is available through the ODD HRM & ALL HRM controls.
ODD HRM morphs the Sine output to a Square wave under manual and voltage control (without attenuation).
ALL HRM morphs from Inverted Saw (manual control fully anti clockwise) through to Sine (manual control set to noon) to Saw (manual control fully clockwise). The HRM MOD CV input has an attenuator.

Here's what Rob has to say about his oscillator module :

The Triple Input Filter :

This is a  4 pole (24dB) multi mode VCF with an unusual topology in that it doesn't have separate outputs for its different responses (LP, HP and BP), but instead it has three inputs and one mixed output. The three inputs are placed upfront of the filters and each input has a Level control that determines the amount of signal that goes into each filter. This way one can dial in specific responses by setting the levels of the respective inputs. This is valid for a single sound applied at the LP input, because this is normalized to the HP and BP inputs. But, one could also input a signal to the LP input, another signal to the HP input and a third signal to the BP input. The output would then be a blend of the first signal treated by the LP filter, the second signal treated by the HP filter and the third signal treated by the BP filter.
The LP, HP & BP inputs are DC-coupled so that also CV signals can be processed.
Both Cutoff frequency and resonance are under manual and CV control. There's a 1V/Oct CV input to the Cutoff frequency and two supplementary FM inputs with attenuators. When no CV is input to the MOD II control, it acts as an overdrive of the resonant peak,  putting emphasis on the harmonics of that peak, delivering a smooth, subtle and very natural distortion effect. Naturally, this works best at higher resonance settings.
This filter will not go into self oscillation. 
Next to the main filter output there's also a VCA output for amplitude modulation of the filter (unattenuated CV input to the VCA and no control over initial gain of the VCA).

Again, some more explanations by Rob :

The Dual Fader :

The Dual Fader is really a very versatile and handy module, that can be used in various ways and at different points in your patches. It has two independent crossfaders/panners with two inputs and two outputs each. Inputs are DC coupled which means it will process CV signals as well as audio signals.

In a two inputs - one output configuration, the channels will act as individually voltage controlled faders.
In a one input - two outputs configuration, the channels will act as individually voltage controlled panners with "energy loss compensation" set at -3dB with the control centered.

You could have one channel set up as a fader for CV signals and the other as a panner for audio signals.

The product of FADER A can be injected into FADER B with the AX TO B LEVEL control so that, for example, you could have a submix of FADER A mixed into FADER B. Depending on the setting of the mode selector switch, the AX TO B signal will be inverted or not.

This AX TO B feature is essential to use the Dual Fader as a ring modulator.
Here's how to set it up as such :
-Put the switch in the AX RM position.
-Patch your carrier signal to A1 IN and open AX TO B LEVEL (your carrier signal can also be a composite signal of A1 and A2).
-Patch your modulator signal into MOD B IN and open the FADE B MOD control.
-Center the FADE B control to cancel out the carrier signal.
-Take output of the ring modulated signal at BX/L OUT.

Each channel has a 20dB boost available to, for example, adapt external line level signals to the signal levels inside the modular. This 20dB boost is applied to the A2 & B2 inputs. A1 & B1 inputs are normalized to the A2 & B2 inputs respectively, so that when no jack is inserted in the inputs A2 & B2, the signals present at A1 & B1 are duplicated and can benefit of the 20dB boost.
Channel B has manual initial gain control over its B1 input.

Examples of use of the Dual Fader :

The above discussed modules together in a compact system provide amazing creative potential, unrivaled by any other MU - 5U manufacturers (exeption made for the Modcan B series). Also, integration of the Hordijk system with my Mos-Lab system is seamless and the resulting instrument performs way above my wildest expectations. Both systems complement each other very well and the Hordijk system breathes new life into my "dusty, old" Mos-Lab which comes out with new attitudes and unheard sounds.

Only one more row in the cab to fill with some Hordijk modules... quite soon, hopefully...

Stay tuned !