This is a beautiful 24dB filter with a brilliant and somewhat rough sound, quite different from the A-108 Transistor Ladder. For technical details, please see Doepfer’s Homepage:

http://www.doepfer.de/a105.htm 

This example uses three A-110 VCOs (sawtooth, one VCO is tuned down 1 oct), cutoff frequency is modulated by an Envelope Generator and the A-155 sequencer (same track that controls VCO pitch), Resonance (called „Q“ here) is controlled by a second A-155 track. Btw., the examples here are not intended for some kind of „scientific“ comparison between modules. On the contrary, I would like to show some characteristics in a somewhat musical context.

Here we go:

http://www.andreaskrebs.de/assets/media/A-105.mp3

Since the A-105 allows for some nice overdrive, we increase the input volume during the track.

Andreas

There are quite a few discussions about the quality of various modular filters / filter manufacturers, etc. which we are happy to see today. Here’s an example of the quite „beefy“ and full Doepfer A-108 6/12/24/48dB Lowpass (Transistor Ladder) Filter. Does it sound lika a Moog? I don’t care too much, since it sounds very fine in its own respect and fits well to all kinds of classical electronic sounds. For technical details of the 8 stage transistor ladder take a look at Doepfer’s homepage:

http://www.doepfer.de/a108.htm 

The example uses three A-110 VCOs as input (all with sawtooth, one VCO is tuned down 1 octave), there is filter key tracking and filter ADSR modulation with varied intensity. You will hear the five different outputs of the filter as follows:

1. 48 dB lowpass (0’00“ and 4’05“),
2. 24 dB lowpass (1’00“ and 4’24“),
3. 12 dB lowpass (1’42“ and 5’00“),
4. 6 dB lowpass (2’20“ and 5’27“) and
5. bandpass filter (3’00“ and 5’48“).

For each output, we start with no resonance (called emphasis here, since this is a kind of Moog clone) and end with full resonance. When using the bandpass, the center frequency is varied as well. After this, we repeat the same thing (slightly different filter center frequency) with input level cranked up so it can distort nicely. The VCOs are driven by an A-155 Sequencer.

Here we go:

http://www.andreaskrebs.de/assets/media/A-108.mp3

Andreas