Friday, 10 March 2017


Null-A2 is an all-in-one analogue synth packed into 42HP. 
PCB set (2) - USD50
White Panel - USD50 
Black Panel - USD60
'B-stock' PCB or aluminium panels - USD40
Shipping for these will be USD20 (includes tracking & signed delivery)

assembled - USD550.

It features:

2 VCOs
1 state variable VCF
1 ladder VCF
1 VC Delay
3 VCAs
2 LFOs
Headphone amp
Clock Divider
Sample & Hold (S&H)
Sloth chaos generator

It does not feature MIDI, micro-processors or any software. 

Current draw:
+12V rail - 135mA
-12V rail - 90mA

There are several presets that run between the switches of the jacks. If you insert a patch-cable into either jack the preset is disconnected.

The interesting one is the signals from the Sequencer, Sloth chaos and Tri from LFO2 are mixed and fed to the S&H sample input. This means it is continually generating stepped and smooth CVs (for there is a Slew pot) that are different but related to everything else that is going on.

The Clock Divider gives divisions of /2, /8, /32 and /128. 

The Sequencer has 4 stages but the direction control can be used to make it count forwards and backwards enabling more complex sequences. In normal operation, the ‘x’ output gives the CV generated by the stages 1 thru to 4, meanwhile the ‘y’ output will give a CV signal generated by stages 4 thru to 1.

The VC Delay can be used to generate reverb type sounds but can also be pushed into making all sorts of unexpected zipper noises and effects when the Time and Feedback pots are turn high.

The third VCA is built into the input of the Ladder VCF. If nothing is patched into the ‘CV VCA’ input, the VCA is always on. 

The Sloth Chaos is a very slow CV generator, it can be used to liven up a patch and create slowly evolving sounds. It cannot be controlled, it does what it wants.

I have a batch of aluminium panels that have minor scratches or scuff marks on them, usually just a couple and not particularly bad, so these are available for USD40 until sold out. Please specify 'B-stock panel' when ordering.


  1. 'atsa good one. got to get soldering again.

  2. When do you sleep? So much good stuff coming out of Australia!

  3. I am setting up to build two of these. Any chance you can post an Eagle file with the silkscreen layer? This board is fairly complex and having that would make finding components much quicker.

  4. I don't use Eagle but happy to supply the gerber file

  5. Hey, where does one find the BOM for the Null-A2? Thanks!

    1. here -

  6. Just purchased one off eBay. LOVE this module!! Solid piece of gear - feature flippin' rich! Thank you X a million!

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  10. Moved my tech question to MuffWiggler so as not to sully this fine blog!

    1. No worries. when Muffs is working again I will have a look