C64 Cynthcart Controller

I’m debating trying out the Cynthcard DIY Controller build:

It looks relatively straightforward. The one thing I can’t figure out is what kind of power I would have to use. The PCB is marked 4V, but aside from that I’m unsure what the smartest option would be. Does anybody have any advice?


I want to build one of these too! Do you already have your commodore?

If I remember right the mod board is powered from the c64? But it was a while back when I watched the vids with dr mix

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Yeah! I had one I used to run MSSIAH on, but it didn’t play as nicely with MIDI, so I ended up scavenged for parts in the end. I have another one that I’m going to try out Cynthcart with. Once I get it working I’ll probably build one of these! If I can figure out the power…

I can’t find where you saw 4v. It’s an arduino so most have a regulator on board that can handle anything from like 6-20v

Dr mix confused about same thing starting at 4:30

Short answer: 9v dc


Thank you!

Looking at the Gerber… now that you’ve mentioned it, it looks like it is just the font that made me think it was 4v. At least it wasn’t just me who was confused!!

In that case… I could just wire in a DC jack somehow. I’ll probably build one then. It’ll take me a while as I’ll need to get some bits and pieces, but I’ll report back. I’ll have some spare PCBs + panels too perhaps, due to the minimum ordering numbers.


Okay, I’ve put in my order for the PCB and the parts I need. It’ll take them a while to arrive, and probably longer for me to build the damn thing, but I’ll put progress here. If anybody wants a PCB a bit cheaper and doesn’t want to have to order from HK directly let me know - though if you are outside the UK it might not make sense with postage.

I plan on building this without the PCB. I’ve got all the parts ready, just need to sit down and figure it out.

I got this interface

and these multiplexer breakout boards

Also I now have all the C64’s out of the in-laws attic, so probably 12 of them.



post must be at least 20 characters…

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ttiwop I know. I thought they were bringing a non functional Commodore monitor, but I ended up with more breadboxes.

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What’s your address? Why? Oh oh no reason.

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mother of god

[post must be 20 cha…]

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A wave of nostalgia hit me and I’m now wondering if I should seek one out, why and resolving that one couldn’t hurt.

I hear @Riggidyboo has a few spare.

Seriously though, for music the C64 is great. The SID chip was one of the first things I used to make music when I got into electronica. It sounds amazing. It’s just a matter of finding a good way to interact with it, and Cynthcart/this panel seem like one of the better ways. I’ve had Eurorack modules, desktop synths, etc, but they all have their own weird flaws.


The PCB and panel sets arrived and I have a few spare. If anybody wants one rather than going through JCLPCB and their minimum order numbers give me a shout and we can work something out.

I really want to do something for Kosmo with my Sid chip, but it’s quite a doozy to understand the datasheet, hopefully I’ll reach that level at some point.

I also want to do a the c64 build tho lol. Are you in the US? I don’t remember. I’d pick up one of the panel/pcb just in case I eventually do it

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I’m in the UK unfortunately, so might not be worth it for you!

As far as building something for Kosmo with the SID…have you looked at the midibox SID? MIDIbox SID

It was the first synth I built. Though I never got more than the patch matrix and LCD with one encoder and a couple of buttons for the control surface before I set it aside because at the time my only MIDI keyboard was USB only and having to patch through the computer was just a pain. And of course a few years ago when I finally got my sequencer working a few days later my SID stopped working and I’ve yet to figure out why :frowning:

But - it’s a highly flexible design so could be easy to adapt a CS to fit in Kosmo…just a matter of deciding which functions you want controls for. Something like the Sammich SID could easily fit behind a Kosmo panel: sammichsid [MIDIbox]

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I was wondering if it is possible / advisable to run the board off the 5v from the c64 power supply. I noticed it has 5v DC but it has AC for the 9v.

Also I think this is ok, would it make any difference if the pots were all 100k?