My build progress

Cool, is this an original design?

I’d like to try the Mauritz Klein version, but I guess I need to shell out for the Patreon because I haven’t found the diagram yet.

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Not yet!

The filter core is similar to this one that you posted:

I looked at the matched pair transistors they use on the x0x box and am using some of them for the exp conv for the cutoff and the current sink - might see if I can use them for the diodes in the filter stages too. That way it may be possible to have a diode ladder and a transistor ladder on the same PCB? is a good resource too.

Once I manage to get a voltage controlled resonance circuit going I’ve got some ideas to try out - feedback some of the original input to counter any bass loss, and see if I can do some analog maths and derive a HP from it.


Today : Quantizer day :slight_smile:

Pic and video here


like usual that sounds great !

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It’s on my to do list too! I beleive Moritz shared the final schematic of the diode VCF in the latest video, look in the description.

The schematic

and a stripboard layout

soon i think a version with Hi or Band pass add :slight_smile:



Finally managed to finish my take on the tuner vco. There’s a few little differences, the ref voltage can be sent to other units in a chain (untested)

It’s only 75 wide to save space.

The front had the locating peg for the rotary switch

Not turned out too bad


And the safety, not sure it’s doing what it’s supposed to but all the controls do something.


Resonance on the VCF looks like it kinda works:

Need to work on the Fc and RES CV ranges/response.
It does self oscillate - but it’s very quiet - need to see what I can do about that.
Then - need to see if I can mix in some of the original signal to try and beat that volume loss when cranking on the resonance.



As long as it sounds awesome, why would you care? :stuck_out_tongue:

I just finished with the latest shipment from our man, Sam.

The store descriptions on these needs to be updated, because there’s an entire drum kit hiding in the Bounce Bounce and the Safety Valve. They are both really great sound sources.

I’m thinking about slapping a vac pack on the gain knobs on these Safety Valves. I love the sound they make when you max the volume knob and sweep the gain.


A triple passive vactrol VCA (maybe more a LPG)

And a patch with it


That was super good! Loved everything about it.

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That’s a cleaver idea. Do you have a schematic with the values of the parts you used?

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This was my evening… I love Frequency Central’s kits, but I gotta have it in Kosmo.



I’m not sure, but If this question is for the Vactrol VCA, here’s the schem i used

VCA - LPG passif


Thanks, I think I’ll give that a try.


I made a diy vactrol with LDR and maybe test with different value for the led resistor

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Look at this one (thx @saint_et_moudulard for the link :wink: )
maybe more interesting ?