Cwejman VCO-2RM Dual Oscillator Review + Demo (Youtube Video)

Cwejman modules have gained the status of the holy grail of modular synthesis over the past few years. Recently I was offered to buy a VCO-2RM second hand for an OK price so jumped the opportunity and got my hands on it. I had tried some Cwejman modules before (including the VCO-2RM) at Schneiders in Berlin and was always intrigued by their classy and beautiful sound. I had read lots of good things about Cwejman stuff on the internet as well. Some critical voices tend to nitpick about the Cwejman sound being too sterile or clinical. I can understand what this criticism is about, as Cwejman really sounds very "precise" but I never saw this as a problem. If you want warm/fuzzy/overdriven sound you can still mangle your audio signal with distortion or waveshapers or whatever is available (and that's a lot!).

Briefly going through the VCO-2RM's features, it is a dual VCO with a wide frequency range (there is also an LFO mode available for both oscillators), 3 FM inputs for each oscillator (exponential FM only!), PWM, sync and a ring modulator. Since the ring modulator is  DC-coupled it can be used with CV signals, making it a VCA. Yes, you can use the VCO-2RM's ring modulator as a full-fledged audio VCA! I tried it, it works. Each VCO has 7 selectable waveforms available (everything from sine to pulse including some odd mixed waveforms). Each VCO can only output one waveform at a time. 

Cwejman VCO-2RM Dual Oscillator

So how does it sound? Well, compared to the vintage oscillators I have experience with (Moog, ARP, Octave, Roland etc.) it strikes me as being "on the spot" as opposed to "warm and organic". So, depending on what you are after it might indeed be a touch "too controllable". Obviously the components Cwejman uses for his modules are so well-selected and precise that there is hardly any room for tolerances or random fluctuations. For me the VCO-2RM really shines once you start modulating it. Feed it with CVs from various sources, amplitude-modulate these CVs with VCAs, sequence everything, well... you will see (and hear) that the VCO-2RM really begs to be modulated, and the sonic possibilities opening up are infinite. As you tweak the VCO-2RM's knobs even a tiny bit of change can make a huge difference in timbre. What I love about it is that it covers everything from classical subtractive to experimental sounds. And did I mention the VCO-2RM tracks like a champ? Tune both oscillators to a specific interval and play them across multiple octaves. Voila! Stays in tune.
For my demo video I used both VCOs and the ring modulator sequenced and modulated by Doepfer A-155 sequencer, A-145 LFO, A-143-9 VC Quadrature LFO, A-140 Envelope Generator, A-149-1 Quantized/Stored Random Voltages, A-133 Dual VC Polarizer and A-183-2 offset generator. The mixed output of the VCO-2RM runs through a STG Soundlabs Sea Devils filter and in part through a Synthrotek Echo. Enjoy!

Modular EBM Drum Patch (Doepfer + MFB)

Play MP3 clip: Modular_EBM_(Doepfer_+_MFB).mp3

Recently I asked myself if you could use a A-149-1 Quantized/Stored Random Voltages module as a noise source for audio. Answer: Yes, you can! But wait, what do random voltages have to do with noise? Well, noise is nothing but random sonic events spread out over the audible range. The A-149-1 spits out random CVs in sync with an external clock that can be way up in the audio range. However, at a certain point when the clock signal gets too fast the A-149-1 stops operating. But still it is fast enough to create some nice lofi-ish digital noise timbres. I used the lower "stored random voltages" section since here the distribution of values is more wide-spread than in the upper half. So, what can you do with noise? Make a snare drum for example. I quickly came up with a snare drum patch sounding pretty much sick & destroyed, using only an MFB Megazwerg AHDSR Envelope and a Doepfer A-133 Dual VC Polarizer serving as VCA.

Doepfer A-149-1 + A-149-2

Now that we have a snare drum, why not make a bass drum as well? For this I used a Doepfer A-143-9 VC Quadrature LFO as a sine oscillator providing the body of the kick. To achieve the clicking attack sound I layered two envelopes modulating the snare drum's VCA: Doepfer A-171-2 VC Slew generator provides a decay while a Doepfer A-140 Envelope acts as a bread-and-butter ADSR. Now to add some more spice I utilized a Doepfer A-149-2 Digital Random Gate module to randomly open up the VCA in addition to the envelope. The A-149-2 is an expansion to the A-149-1 described above. It outputs random high and low voltage states synced to the upper half of the A-149-1. A great combo by the way! The result is a sine sub-bass that comes in randomly between the bass drum hits. I also added some random pitch changes to the sine wave via the Doepfer-A149-1's upper half which provides voltages that are quantized to semitones. Very handy.

MFB Drum-07 Hihat / Cymbal module

For hihats and cymbals I used the MFB Drum-07 module which is the modular version of the MFB-522's hihat and cymbal section with some slight changes plus CV-able parameters. It has been discontinued and I highly recommend you pick one up if you can find it as it makes some wonderful sounds. I treated the hihat with some Doepfer A-114 ring modulation and the cymbals with bandpass filtering using MFB Megazwerg's multimode filter. 

MFB Kraftzwerg

Chiming in later we have some delay via MFB Megazwerg with CVed delay time and random freezes. Last not least you'll hear a bassline coming out of good ol' MFB Kraftzwerg. Nothing like a rough EBM bassline going along with your modular drumset. Enjoy!

Doepfer A-110-2 Basic VCO Demo

Warning: This is a hardcore technical modular synth post! I recently got my hands on the first copy of a Doepfer A-110-2 Basic VCO Eurorack module that was ever sold worldwide. It showed up at Schneidersladen in Berlin and I was the lucky one, the first one!

Doepfer A-110-2 Basic VCO and friends

The A-110-2 is the follow-up to the A-110-1 which has been selling for many years now. The A-110-2's basic features: Three waveforms (saw, square and triangle), 3-way octave switch, exponential FM (with attenuator), linear FM (without attenuator), pulsewidth modulation (with attenuator), hard and soft sync. It is only 8 units wide which is really cool. I decided to make a demo showcasing the basic and raw oscillator sound as well as two more musical snippets demonstrating various features of the A-110-2. In all examples whenever all three waveforms are presented they appear with their original volume in relation to one another. Warning: The audio files are big! Format: 44.1kHz, 16 Bit mono.

Let's start with the basic waveforms. You are hearing saw, square (50% duty cycle) and triangle in a range of 7.5 octaves. For pitch I used a Doepfer A-145 LFO (triangle waveform) through a Doepfer A-156 quantizer, set to output only 5ths and octaves:

Doepfer_A-110-2_Waveforms_Saw_Square_Tri.wav

Now let's add some pulse width modulation to the square wave. PWM source is a slowly moving sine wave LFO:

Doepfer_A-110-2_PWM.wav

The A-110-2 has a nice feature: Linear FM. In this patch a Doepfer A-171-2 VC Slew Processor serves as the source for the modulation with a frequency modulated sawish triangle waveform. The result is not as dramatic as with Exp FM. Again saw, square and triangle:

Doepfer_A-110-2_LinFM_Saw_Square_Tri.wav

Now for exponential FM. Modulation source is the Doepfer A-171-2 with the same configuration as in the Linear FM patch above:

Doepfer_A-110-2_ExpFM_Saw_Square_Tri.wav

Let's take a look at hard sync. With each of the 3 waveforms (saw, square and triangle) you first hear the A-110-2 slaved to a steady-pitch master oscillator while being pitch-modulated by an EHX 8-step sequencer. After a few seconds I add some LFO modulation via the EXP FM input. You can hear the timbre of the slaved oscillator changing along with the LFO swings:

Doepfer_A-110-2_HardSync_Saw_Square_Tri.wav

Now it's soft sync. I must admit that I haven't managed to fully wrap my head around the theoretical implications of soft vs. hard sync. All I can say is that soft sync does not reset the waveform to 0 when the master oscillator finishes a cycle (unlike hard sync) so you won't get any such dramatic changes in timbre as in hard sync. Interestingly modulating the slaved oscillator's frequency does change the perceived pitch as well (again unlike hard sync). Same modulation as in the previous clip:

Doepfer_A-110-2_SoftSync_Saw_Square_Tri.wav

Now let's go "all in". I have put together two patches that are more musical than the above examples to showcase what the A-110-2 can do if you combine all those nifty features. What you hear in clip 1 is all three waveforms cycled through a Doepfer A-152 quad sequential switch (accounting for some clicking audio glitches here and there) with some random resetting. I have added PWM, Lin FM and Exp FM from various sources as well as hard sync. No filtering, just some amplitude modulation via MFB Megazwerg VCA (AHDSR modulated):

Doepfer_A-110-2_All_In_1.wav

The following patch circumvents the VCA completely. However, there is some amplitude modulation on the saw wave. Later in the clip I start tweaking some of the parameters. Again, no filtering:

Doepfer_A-110-2_All_In_2.wav

I hope I have managed to give you a good overview of the Doepfer A-110-2 basic sound and its most important features. Enjoy the demos!

Korg Mono/Poly vs. EHX 8-Step Sequencer & Doepfer Modular Skiff (Youtube video)

Today I wanted to try out how I could spice up a simple 3-note arpeggio on my Korg Mono/Poly by sending some CV modulation to its filter CV input. So what you are hearing here is the Mono/Poly with its lowpass filter cutoff frequency being externally modulated by a small modular rig. I just added some delay and reverb from the Korg SDD-1000 and Dynacord DRP-20.

Running on its internal arpeggiator the Mono/Poly sends out a gate signal for every note. I took this gate signal and used it as a clock source to synchronize an Electro Harmonix 8-Step Program analog sequencer and a Pittsburgh Modular Cell 48 case with 5 Doepfer Eurorack modules.

Korg Mono/Poly

Electro Harmonix 8-Step Program Sequencer

Doepfer A-143-9, A-151, A-138m, A-133 and A-140

My latest modular acquisition is the Doepfer A-138m 4x4 matrix mixer. It really doesn't look flashy at all nor does it have a fancy name. But looks can be deceiving. This IS a highly versatile and mighty tool. What does it do? Well, the principle is simple: It has 4 inputs and 4 outputs. You can route any input (arranged in horizontal rows) to any output (arranged in vertical columns) with whatever level you like. One really useful feature is that you can set each output column to "bipolar mode", meaning you can turn each level knob to the center position for no signal or clockwise for positive and counter-clockwise for negative (inverted) signal. That's a great thing for CV signals, but you can also use it for audio signals for example in order to change the characteristics of a filter or for M/S processing of a stereo audio signal.

So here you can see (and hear) the A-138m in action. The A-143-9 VC Quadrature LFO is providing the Mono/Poly's filter with some nice audio-rate FM while the A-140 ADSR Envelope Generator modulates the amount of LFO signal going through the A-133 Dual VC Polarizer. You can clearly spot the effect of the ADSR in the youtube clip as it creates those "a-u" and "u-a" vowel sounds. The A-151 Sequential Switch is a real funky tool, too. It can be used to cycle through 4 independent signals by routing 4 inputs to 1 output or 1 input to 4 outputs at a time, making for some very interesting rhythmical modulations. You can use it both on CV and audio signals. Hey, you can even build a sequencer with it but I will go into this another time.
This skiff really is a fun little toolbox with lots of functionality in such a small space. Enjoy the demo!