Analogue Systems RS-Integrator modular synthesiser with Doepfer sequencing modules.

This is an amazing modular synth made in Cornwall by Bob Williams.

A friend of mine came back from Japan last year with a Roland System 100-M and we used it to make some music at his house. I had read about modular synths but never actually used one. I thought it was amazing, you could just sit and think about synthesis and come up with an idea for a sound and then actually patch it up and hear it. With modular synths you can get right into the nuts and bolts of synthesis without having to actually do any soldering, it's like being able to make a new synth every day in some respects. So after a few months fiddling with the 100-M round at his place, I knew I had to buy a modular. I couldn't really afford the big vintage or new systems and the Doepfer seemed cool but I always like having something a bit different to what everyone else has. Then a small AS modular came up in the Sound On Sound classifieds so my friend with the 100-M drove me up to Reading to pick it up (thanks Nick).
I used it for a while and then I ordered another case from Bob Williams and bought some more modules from the secondhand ads in Sound On Sound. Recently I added a step sequencer from Doepfer which is a lot of fun. MIDI is handled by a Kenton Pro Solo.

What can I say about this synth? I haven't used lots of modulars so I can't really compare, I can just give my impressions:

The oscillators sound good and offer lots of waveshapes, modulation possibilities and hard sync, and they stay in tune over a wide range and can even be used as LFOs.
The 24dB lowpass filter sounds nice and moogy, the multimode filter has a different character that complements it nicely, and both can be overdriven for a nice warm distortion if you want it. There are plenty of inputs and outputs, including a few weird oned like a "RES" output and input on the multimode filter that you can use like an effects send within the filter (I can't explain it but it's interesting).
The LFOs have a wide range up into the audio spectrum (although it's hard to keep them in tune if using them for audio.) Just like the VCOs, they have a CV input and hard sync. The CV is Hz/V instead of V/Oct though which is a bit of a pain.
The comb filter module is fun and aggressive, the fixed 8-band filter is a bit boring but could be useful on occassion; a CV input or two would've made it more fun.
The VCAs, multiples, mixers, adapters and divider work nicely and cleanly.
The envelopes are very fast when you need them to be and have some interesting looping modes - you can use them as LFOs with unusual waveforms among other things.
The noise on the Noise/S&H module is a bit quiet but everything works.
The ring modulator sounds great, very good for Mr Fingers bass sounds!
The envelope follower and pitch-to-voltage module is fun although the pitch to voltage doesn't track very accurately. Bob Williams says he can improve it as mine is quite an early example so I will have to send it in for a service.
The layout of the modules is good, things can get confusing with mini-jack patch leads everywhere and the sockets being quite close together but I think it's a price worth paying for the compactness of the system. Some of the mini-jack connections can be a bit dodgy.

I had a lot of fun using the step sequencer on an EML system so I wanted to have step sequencer for my modular. I decided on the Doepfer A-155 because it works with the Analogue Systems case, and it's cheap! It's not something I see myself using a lot, but it's great fun for coming up with unexpected acid lines and out-of-tune sequences, or hooking up to the Bel Delay for some crazy pitched-echo effects. It has some cool features including sample & hold and glide, and with the A-150 VC switch you can get it to do 16 steps instead of just 8.

Module overview:

AS-15 Case x2
RS-30 Pitch to Voltage / Envelope Follower
RS-170 Multiples x2
RS-95 Oscillator x2
RS-90 Oscillator (almost the same as the RS-95, just a bit less flexible)
RS-200 Divider - useful for sub-octaves a la SH101 or for clock-dividing duties
RS-20 Ring Modulator and Multiples
RS-165 Signal Mixer
RS-40 Noise / S&H
RS-80 LFO x2
RS-100 Low Pass Filter
RS-110 Multimode Filter
RS-120 Comb Filter (Phaser)
RS-210 Fixed Filter (EQ)
RS-60 Envelope x3
RS-180 VCA x2
RS-160 CV Mixer
RS-270 Adapters
Doepfer A-155 Sequencer
Doepfer A-150 Dual Voltage-Controlled Switch - lets you use the A-155 as a 16-step device.
Collapse Of The Wave Function blanking panel!


Some sounds I made using the Analogue Systems modular:

AS01 - single oscillator through the RS-100 filter with velocity controlling the VCA for a pseudo-echo effect (no outboard delay was used).
AS02 - similar to the above patch but with three oscillators in unison.
AS03 - a bass sound using oscillator sync.
AS04 - a sound using oscillator FM. A single oscillator is used and the modulating wave is generated using an octave divider to avoid the inharmonic effects normally caused by oscillator drift when attempting FM on analogue synths.
AS05 - a bass sound using ring modulation played by the Doepfer sequencer with drums from the K2000 sequencer. One step only in the sequence has fairly extreme filter modulation by an LFO.
AS06 - another FM bass sound, this time two oscillators are synced together and the octave divider is used again to avoid tuning inconsistencies. The filter is the RS-110 modulated by sample and hold which is retriggered for each note, and the drums are from the K2000.
AS07 - clocking the sequencer from an oscillator at audio frequencies allows some more digital-sounding waveforms to be made. There is some subtle modulation of the wave shape using sample and hold triggered by each key-press.
AS08 - two oscillators are both synced to a third which is not present in the audio output. The pitches of the two slave oscillators are both modulated by note velocity but for one of them it is inverted. The oscillators are panned hard left and right and I twiddled the tuning knobs while it was playing.
AS09 - there are two sawtooth oscillators tuned a fifth apart and a third oscillator playing a sinewave one octave below (CS60-style). All this goes through the RS-100 filter which is affected by note velocity as well as an envelope with fairly slow attack. Two of the oscillators have some extremely subtle pitch modulation from independent LFOs.
AS10 - just two oscillators through the RS-100 filter. One is set to a descending sawtooth wave and the other to an ascending sawtooth. The interference between the two waves makes a nice sound similar to PWM.
AS11 - three oscillators tuned to a chord, each set to respond to pitchbend by different amounts (and in one case by a negative amount) so that unusual portamento effects between chords are created.
AS12 - a simple two oscillator sound through the comb filter which is modulated by an LFO for some phasing effects.
AS13 - using the synth as a drum machine: the kick drum is just a square wave through the RS-100 filter with one envelope controlling the volume and filter cutoff and another modulating the pitch. The weird hihat sound is a second square wave being modulated by a sine wave from the third oscillator, the pitches are controlled by the A-155 sequencer. The snare is just white noise through the RS-110 filter and the comb filter which is just used to add distortion and to make echoes.
AS14 - two oscillators tuned a fifth apart through the RS-110 filter, the third oscillator has a slow attack and has its pitch modulated by the A-155 sequencer. Echo from the Lexinc MPX1.
AS15 - two oscillators in unison both modulated by a very fast LFO that dies away extremely quickly, the third oscillator is through a filter which is modulated by a looping envelope.
AS16 - one oscillator simply goes through the low pass filter, the other one is modulated by the A-155 sequencer, which is triggered each time a key is pressed. The rate of the sequencer clock is subtly modulated by one of the LFOs and the pulse width of oscillator two is modulated by another. Reverb from the MPX1.
AS17 - two oscillators tuned two octaves apart go through the RS-110 in high-pass mode, which is modulated by an LFO. Both the square and the sawtooth outputs from oscillator three are tuned an octave below and processed by the RS-100 filter.
AS18 - first you hear oscillator two which is outputting a pulse wave synced to oscillator one and having its pitch swept by an LFO. At the same time the pulse width is modulated by the oscillator's own sine output. Next you hear oscillator one which has the square and sawtooth outputs sent to a voltage controlled switch which is switching between the two waveforms at exactly one quarter of the frequency of each note, so you get quite a complex waveform, especially as the pulse width is also being swept by an LFO. Finally you hear both oscillators together.
AS19 - my voice going into the ring modulator, and also into the pitch to voltage converter, which is used to control the pitch of the oscillator used as the second input to the ring mod.
AS20 - two oscillators both slowly sweeping between sawtooth and triangle waves at different rates, both playing different eight-note sequences from the A-155 sequencer, both going into the ring modulator. The output goes into the RS-110 filter in lowpass mode, which is modulated by an envelope triggered on certain steps of the sequence for an "accent" effect. The output from the filter is split into two, one copy going straight to the VCA and the second copy going via the comb filter. During this demo the cutoff frequency of the filter is adjusted and the amount of signal coming from the comb filter is gradually increased.


Analogue Systems website here
Harmony Central reviews here
Sound On Sound review here