AndreasKrebsBlog

The A-118 is an analog noise generator which can produce continuous random voltages as well. Easy to use and quite versatile.

Details can be found on Doepfer’s homepage:

 http://www.doepfer.de/a118.htm

We start with some pure “white” noise, until ca. 0:22. Then I blend over to the “colored” noise (I’ve put white and colored outputs into an A-134-1 VC Panner, which can do crossfading as well). “Blue” and “Red” knobs are both set to zero. After ca. 0:35, I start increasing the “Blue” noise (high frequencies) until maximum. Starting around 0:53, I’m, adding “Red” noise as well, also until max is reached. After 1:10, the “Blue” noise is diminished, after 1:25, the “Red” one as well.

Starting at 1:43, we have some white noise put through an A-108 VCF (bandpass output used), to show some of the random voltage capabilities. At first, modulation intensity (on the A-108) is increased, after 2:05, I start turning up the “Red” knob - which influences the behaviour of the random voltages. After this, some variations with increased resonance on the A-108.

Here we go:

http://www.andreaskrebs.de/assets/media/A-118.mp3

Have fun,

Andreas

The A 101-2 is a vactrol based lowpass gate. Any questions? Lowpass gates (LPGs) are devies that can act as lowpass filters as well as amplifiers. And a combination of both. So, well, why not simply use a lowpass filter and a VCA? Two reasons: A LPG can be switched between these three modes. In case of Doepfer’s even voltage controlled by means of a gate signal. And the filter will behave different if used “pure” or in VCF/VCA combination (especially the amount of resonance). Ah, and a vactrol based VCA sounds different from a “normal” VCA (well, that’s three reasons…)

For technical details, take a look at Doepfer’s homepage:

http://www.doepfer.de/a1012.htm

As in most filter demo patches, there are three A-110 VCOs (sawtooth waves used, 1 VCO 1 oct down) driven by an A-155/156 sequencer, mixed and sent into the A-101-2 LPG. LPG modes are switched by a random module (A-149-2) synced to the Sequencer. Filter cutoff and / or amplification is controlled by an A-149-1 random module and (with attenuator) by an A-140 ADSR. Finally, we go into an A-132-3 VCA. The latter VCA is not essentially necessary, since our “filter” can act as a VCA, too, but it will show some interesting effects, since both VCAs are quite different.

We start with no filter resonance, a moderate LPG input level, no ADSR modulation on the LPG as well as on the A-132-3. Then I start increasing ADSR modulation on the LPG. Next (around 0:50) filter resonance is increased, followed by input level (we get some fine distortion from the LPG). Then the A-132-3 is modulated by the A-140 (instead of simple “gain” level). And some final tweaks of modulation dephts / resonance level.

Here we go:

http://www.andreaskrebs.de/assets/media/A-101-2.mp3

Have fun,

Andreas

This is an interesting module if you are into distortion, low-fi and all kind of weird effects. It has two CV inputs: one for a parameter (e.g. number of bits, delay length) of the selected function, the other for sampling rate. The Bit cruncher offers 16 different functions which can be selected via switch. As a sound source, I’m using three A-110 VCOs through an A-108 VCF and then through an A-132-3 VCA. Everything is driven by a sequencer. VCA output is sent into the Bit Cruncer, which is modulated by two slow triangle LFOs.

For each Bit Cruncher function, I’m starting around the highest sampling rate, after ca. 30 seconds we can hear what happens with the lowest sampling rate. The LFO which modulates the function’s parameter is a bit faster, so you should hear a lot of combinations of both modulations:

Here we go:

1. bit crushing:
   http://www.andreaskrebs.de/assets/media/A-189-1_function_01.mp3
2. AND:
   http://www.andreaskrebs.de/assets/media/A-189-1_function02.mp3
3. OR:
   http://www.andreaskrebs.de/assets/media/A-189-1_function03.mp3
4. XOR:
   http://www.andreaskrebs.de/assets/media/A-189-1_function04.mp3
5. bit shift right:
   http://www.andreaskrebs.de/assets/media/A-189-1_function05.mp3
6. bit shift left:
   http://www.andreaskrebs.de/assets/media/A-189-1_function06.mp3
7. multiplication:
   http://www.andreaskrebs.de/assets/media/A-189-1_function07.mp3
8. compare and complement:
   http://www.andreaskrebs.de/assets/media/A-189-1_function08.mp3
9. compare and absolute:
   http://www.andreaskrebs.de/assets/media/A-189-1_function09.mp3
10. addition:
    http://www.andreaskrebs.de/assets/media/A-189-1_function10.mp3
11. addition with BC swap:
    http://www.andreaskrebs.de/assets/media/A-189-1_function11.mp3
12. short delay 1 with dynamic normalization:
    http://www.andreaskrebs.de/assets/media/A-189-1_function12.mp3
13. short delay 2:
    http://www.andreaskrebs.de/assets/media/A-189-1_function13.mp3
14. short delay 3:
    http://www.andreaskrebs.de/assets/media/A-189-1_function14.mp3
15. short delay 4:
    http://www.andreaskrebs.de/assets/media/A-189-1_function15.mp3
16. four stafes FIR filter:
    http://www.andreaskrebs.de/assets/media/A-189-1_function16.mp3

Technical details can be found on Doepfer’s homepage:

http://www.doepfer.de/a1891.htm

Have fun,
Andreas

The A-117 is a versatile digital niose generator. It has two parts: an “808 Sound Source” which has a 6-oscillator output (cymbals) and a 2-oscillator output (cowbell) for percussive sounds known from an 808-style rhythm machine. The sound example here starts with the 6 oscillators output (through an A-132-3 VCA, controlled by a sequencer-triggered A-140 ADSR) and blends over to the 2 oscillators output (same patch). Quite a nice thing, if you like that kind of machines.

Then, we crossfade to the digital noise, which is  a kind of “Geiger-Counter”, here tempo-synced to the sequencer (i.e. the random clicks stay within the rhythm - just randomly switched on or off, which makes it quite usable in a musical context). Tempo / tuning of the digital noise can either be controlled manually or with an external clock source (sequencer, square LFO/VCO waveform). Later, the tempo is increased, until we have something that reminds of “normal” white noise:

http://www.andreaskrebs.de/assets/media/A-117.mp3

Detailed information can be found on Doepfer’s Homepage:

http://www.doepfer.de/a117.htm

Andreas