Where Is The Sub-Oscillator On The Moog ?
I pre-ordered my Mother 32 as soon as Moog announced it. After receiving it, the poor synth sat for months as I was disappointed that I couldn't easily access the sounds the baby Moog was capable of producing. It seemed that Moog omitted many essential features and one of those omissions was a sub-oscillator. Also, I was used to working with my Bass Station II and not a modular type synthesizer.
Rather than part with the baby modular, I decided to double down and purchased another Mother 32 along with a 2 tier stand kit. Initially this seemed like a great idea but I quickly understood that unless I was using the sequencers on both synths that my money would be better spent on building on a single Mother 32's strengths. So I sold one of the Mother 32 voices, kept the case, and went about choosing modules to expand the Mother 32.
I needed a 2nd oscillator and I noticed several VCOs didn't have sub-oscillator outputs. I learned that synth knob wigglers take the original VCO output and divide the frequency by 2 to produce an output one octave down from the original. This simple function is commonly performed by flip flop circuits. The resulting sub-frequency is then mixed with the original VCO signal by using a mixer. There are modules such as the Blue Lantern Subharmonics Generator that are dedicated for the purpose of providing sub-oscillator outputs but another option is to use a clock divider such as the low cost Doepfer A-160-1.
The Doepfer A-160-1 and the Mother 32
I chose the Doepfer A-160-1 module for my Mother 32 outfit for a variety of reasons.
1. The module is useful for more than sub-oscillator tones.
2. It's intuitive unlike more complicated modules such as Function or Maths.
3. It's cheap, around 80.00 USD new
4. It's small, 4hp, and it has six blinking LEDs. :)
If you've prepared your Mother 32 for expansion then adding an A-160-2 isn't a big deal. I've expanded my Mother 32 with a 2 tier rack kit, Moog 60hp skiff, and TipTop μZeus micro power supply with flying bus boards.
Patching the Mother 32 and the Doepfer A-160-2
Using the A-160-2 is super easy, start by feeding the Trig In with either of the Mother 32's VCO outputs. Next, connect one of the outputs of the A-160-2 to your EXT AUDIO jack on the Mother 32. The /2 output is one octave down, the /4 is two octaves down, and so on. Then use the Mother 32's MIX knob to blend the original VCO with your new sub-oscillator. If you desire more bass madness, connect a second output from the A-160-2 to MIX 1, and the original output you choose to MIX 2. Then take a patch cable and patch VC MIX to EXT AUDIO. Now you can blend the amount of sub-oscillator as before in addition to balancing the mix of the two sub-oscillators using the VC MIX knob. You could even modulate the VC MIX with the LFO by patching one of the LFO outputs to the VC MIX CTRL.