Tom Hall put a comment into a previous post about the Doepfer A-185-2 module, and reminded me that I’ve really wanted to talk about what an exceptional and useful module it could be for almost anyone, but especially someone that is focused on maintaining 1 V/Oct pitch scaling even when you are heavily modulating the pitch. It’s called a “Precision CV Added”, which is pretty clear labeling: it adds CV voltages, but maintains a strict throughput of 1 V/Oct scaling.
Prior to getting this module, I tried modulating using smaller and/or ‘cooler’ modules such as the Intellijel Unity Mixer, my Synovatron CV Tools and a variety of other mixers. If the mixers didn’t have any gain (Unity, Manhattan), the pitch CV would lag – and octaves weren’t matching up. Mixers with gain could scale up to suit, but were almost impossible to tune correctly – it’s really hard to tune scaling. Then I stumbled on the A-185-2 and haven’t gone without at least one ever since then.
Here are some things you can do:
- Precision mixing: This is the core duty of the
185. You put in your 1 V/Oct pitch voltage (from a MIDI-to-CV converter or sequencer),
then add other voltages that will be used to create exponential pitch
modulations. LFO’s, other oscillators, envelopes, slews – you can spend months
trying every voltage in your system as a pitch modulation. Huge fun!
- Attenuated precision mixing: Put your primary
pitch voltage into any input other than the top one. Then put a modulation into
the top voltage and use the attenuator to set the modulation amount. This
control is a simple attenuator for the top-most input, but it really handy for
FM and vibrato effects.
- Pitch and Modulation Inversion: The switch on
each input allows you to turn on (left), turn off (center) or invert (left) the
input’s effect on the mix. You can do some rather insane stuff, including
keyboard inversion (invert the pitch input), more complex mixing (invert some
envelopes for dipped modulation) and performance-time on/off switching. But the
inversion is something that takes practice before you fall in love.
- Octave switching: A secret addition to this module
is the fact that 1V voltage is normalled to each input. This means that any
inputs that don’t have voltages coming in can be used to add (+ switched) or
subtract (- switched) and octave from the main CV input. Since there are
multiple CV inputs, you can actually add/subtract up to 3 octaves in addition
to the standard voltage input.
- Arbitrary pitch shifting: That top-most input
channel is really special; not only does it normal to 1V input, but that 1V value
runs through the attenuator. So you can set this channel to go down a fifth (7
semitones) to create more interesting pitch sequencing. Now, if you have this
set up to a fifth, and use one of the other channels for octave switching, you
can go [- octave], [- fifth], [unshifted], [+ fourth], [+ octave]. Put in a
simple sequence, but actively switch between these options and you’ll find a
real nice location for live performance.
- Buffered multiple: Whatever is created from the
precision mix is sent out all three outputs – and these are buffered. So you
can use them for oscillator inputs and never get any pitch sag.
- Output flip: There is also an inverted output, which may seem a little silly – except that some functions (like FM routing) can actually benefit from inverted output. I see so few people trying inverted modulation – and this dedicated output is actually a good reminder to keep trying it out!
Hopefully this gives you a reason to give this module a try. Totally worth the $99 you’ll have to spend to get one into your system.