All About Topogram

Topogram is a sequential soft key generator capable of splitting live video and patterns into discrete bands for colorization and control. Edge transitions feature voltage controlled gain for creating hard edges or smooth gradients. Upper and lower thresholds for the keying range may be voltage controlled separately.

  • Topogram takes simple inputs and slices them up. Six non overlapping regions can be patched out for 6 band colorizer patterns, along with another 8 outputs which group and span multiple ranges.
  • Driven with LFOs and low frequency envelopes, Topogram becomes a frequency independent sub-event generator for animation control of your patch.
  • Topogram features elevated technical and performance specifications, and is the result of years of research and testing of discrete analogue video circuitry. The signal path is fully active, and CV attenuverters have a deadband range in the center. The circuit is entirely analogue.


  • Width, 16HP
  • Mounting Depth, 32mm
  • Power +12V @ 200mA
  • Power -12V @ 200mA


Other Resources


posting this nugget of information from Lars…

0V, 0.25V, 0.5V, 0.75V, 1V at full range. It’s an evenly weighted spread.

The top and bottom rows are non inverted and inverted variations. The middle row are combinations (analog MIN logic). The front panel illustrates which keys are combined.

of course, discrete voltages are just identifying the center of the edge’s slope, since these are soft keys. So with softer key edges, the identified voltages fall at medium gray (0.5V) relative to the output slopes.

So the middle row span regions… at full scale they are…
0V to 0.25V
0.25V to 0.5V
0.5V to 0.75V
0.75V to 1V

And if you want maximum discrete regions (like for a colorizer) you can get 6 separate bands.
Below 0V (key 1 inverted)

Above 1V (key 5 non-inverted)

really the key thresholds are just center points. Each key has its own 0V to 1V slope as well (controlled by the gain control.) Since gain and threshold are separately defined, you can find some really interesting patterns by modulating each separately.

If you mult a CV source to both upper and lower threshold controls, you can achieve some alternate control methods as well. With CV subtracting from lower and adding to upper, you have “range expansion”, with it adding to lower and subtracting from upper, you have “range compression”, and with CV adding or subtracting from both, you have a “range sweep.”


Just received my new Topogram! Just checking - this module doesn’t include the quick-start user manual / guide, correct?

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Correct. Congrats on finding one!


Another few patching nuggets from FB thread for the archives:

[Lars Larsen]
patch a single luma video source into “input”, then patch as many outputs to as many colors as possible-- going to all 6 inputs on Cortex then setting up an additive blend is a good way to get plenty of variety. set the left knob low, the right knob high. try modulating the gain with a video pattern – very unique function in this case, like modulating 5 doorways in parallel.

[Robin Burke]
Send all 6 outs from the Topogram to two Passages & then bring a Senory Translator & other modulation sources into play

[Luix Bot]
feed it a lfo (like pendulum 0v-1v) and convert it into complex multi output LFO

[Nichole Pichon]
use the thru output as feedback into the gain/upper/lower inputs

polar fringe pos/neg key outs into the upper/lower inputs makes for a crazy colorization patch basis

topogram thru output goes into doorway source in

premixing video with slow strobing CV before going to topogram input

U/V outputs from mapper into upper/lower ins. Y from mapper into source of topogram

we use a reverselandfill matrix mixer to mix 4 outs from the topogram together.

sensory translator + topogram outs going into a passage is great fun for audio reactive patching


If I were theoretically able to get my hands on a Topogram, would it have enough bandwidth to handle 1080i and stay reasonably sharp?

And will there be a Gen3 equivalent? Looking for a multi-zone CV keyer in the vein of the EAB Videolab, with the ability to plug external video and/or voltages into each zone. I know about the proposed posterizer from Reverse Landfill. Hoping for a module that can handle RGB sources, although I know that’s a big ask. Such a beast would not fit into a Gen3 form factor. It’s just that I don’t relish the thought of three separate modules – keeping hard key zone edges aligned while under CV control might be impossible.


For reference, here is the sort of thing I want to achieve
(EAB Videolab II + Fairlight CVI)
Warning: intense strobe / epileptic seizure risk


Yes. Twenty additional characters to make the forum bot happy.

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Cool beans. If one becomes available I may snatch it up, unless something better is announced.

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this might be interesting to your search!

Video Colorizer & Sequencer

Inspirations: classic multiband keyer/colorizers, Topogram, Marble Index, Video Blending Matrix, Amplitude Classifier.

so this is not set in stone at all in fact the “road map” has had a bunch of deviations from the looks of it already. However topogram being listed as an inspiration is a good sign. So look forward to some kind of automata “video colorizer” that will at least pull some inspiration from topogram.

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Yeah!! That sounds epic. But it won’t be soon.


Fantastic news, I scored a Topogram on Reverb.

Is there more documentation other than what’s on this page?

To turn Topogram into a full-blown colorizer, my plan is to patch the outputs into 2x SMX3, and then sum the outputs of the SMX3s. Is this a viable plan?

This is all of the documentation currently available for Topogram. 2x SMX3 would be a great destination for all of Topogram’s outputs.