Doepfer A-149-1

A-149-1… with a name like that, what more could you want to know? Ok, maybe you’re not an alpha-numeric savant, tuned into the idiosyncrasies of Doepfer’s model numbers, and you still don’t know a thing. I guess we’ll have to belabor the point with words…

The essence of the A-149-1 is a clocked, stepped random source, apparently based off of Buchla’s Source of Uncertainty. It offers two, separately clocked sections, with two outputs each. Now, a clocked, stepped, random source is nothing particularly special, you can achieve that with a classic sample and hold circuit, normalled to white noise. What makes the A-149-1 special is that you are given control over the randomness. But that control is much more precious than what can be achieved by simply attenuating the output of an S&H, and I imagine even differs from the results which can be yielded by feeding colored noise into a S&H circuit.

So, what’s are these special controls?

The top section, Quantized Random Voltages, offers two quantized outputs, and gives you control over the number of quantized steps available. The top output offers between two and seven quantized steps (tuned for octaves). The bottom output ranges from two to sixty-four quantized steps (tuned for semitones). The knob/CV on this section affects both outputs, turning the knob clockwise adds steps to the quantization of the first output, and exponentially increases the number of steps on the second output. Having control over the number of random steps available is a pretty cool trick. This section may be “musical” but it’s also great for modulating any old parameter you like. I tend to use these to modulate Mallet and Geometry on Elements, or the Shape on STO.

The bottom section is my favorite, the Stored Random Voltages. The controls on this section allow you to determine the probabilistic distribution of the bottom output. The top output has an equal chance of outputting any voltage, high to low. Whereas the the control knob (and voltages) allow you to select, or modulate, a “center point” on the bottom output. The random voltages generated there are very likely to be extremely close to the center voltage, but increasingly less likely as they stray further and further away from center. Normally, in order to dial-in a random voltage I’m forced to use attenuation. But that sets a hard limit on the range of possible voltages, “here, but no further.” By means of controlling the probability of distribution, I am able to set a sweet spot for the voltages to center on, but there is still the possibility of deviation from that norm. So I have control, but am also able to maintain a greater degree of randomness. I really wish Doepfer would drop a Dual Stored Random Voltage module. I’d scoop it up in a hurry. I really do love it.

Overall, it’s a great source of stepped random voltages, which offers up some uncommon and powerful ways to exercise influence over the voltages produced. If this is the kind of stuff offered up by the Buchla school of synthesis, no wonder its so sought after, it’s all at once unusual, intuitive and creative. It’s a rare patch when I don’t have the A-149-1 fully utilized (or more, with multiples and S&H to take it up to eleven).

 

Tips and Tricks:
The clock inputs aren’t just necessary to run the two sections of the module, they’re a great way to sync it up using clocks, dividers, logics and other gate/clock modulators. Don’t forget Mutable Instruments Branches, ever the fun gate/clock randomizer.

If you have a clock divider and sample and hold on hand, you can clock the A-149-1 at a faster rate, and feed one of the sections outputs to the S&H clocked at a slower rate. There is a reason my A-149-1 lives right between the RCD and Dual S&H in my rack.

For melodies, I like to send the main clock to the Quantized Random Voltage section, I send the bottom output directly to a precision adder, but I feed the N+1 into a S&H, which I usually trigger every eighth or sixteenth beet. I really like the Doepfer Precision Adder for this, because if you simply add both voltages they can get a bit out of hand. I find that inverting the bottom output (the semitones) keeps it in a much nicer range.

Attenuate! I made a somewhat unfavorable comparison between attenuation and the control of the A-149-1. While attenuation cannot accomplish what the quantization and probabilistic distribution controls can, neither can they accomplish what attenuation can. Use them in conjunction with one another to really shape your sound.

Invert: Super basic, yes, but the A-149-1 only outputs positive voltages, so you’re going to need a signal inverter of some sort if you need to go negative. As mentioned earlier, this is important if you are adding voltages from two outputs.

 

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Honorable Mentions
Doepfer A-149-1
Doepfer A-148
Doepfer A-185-2
4MS Rotating Clock Divider