Hero and Sidekick VCOs

Oh this is cool, I’ve been slowly plodding away on a mash up of the Kassu and the LMNC designs so I’m going to have a look and see how you solved some of the issues/differences between the two.

edit: This is going to take a while to understand, there’s a lot going on here. Good work!

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Don’t order yet. (Not too late, I hope.) I realized I forgot to update the Sidekick panel Gerbers. The horizontal jack holes are too small. Nothing a drill can’t fix but might as well get it right. I’ll update the repo soon. Repo’s updated now.

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Not too late, though I’m also not afraid to bust out the drill press :grinning:

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Nice work!

I’ve been working on a similar VCO design - buffered/ scaled waveform outs, sine wave shaper, and switchable sync.

You say the 3340 version/ type is probably not important - remember that the pulse output biasing resistor is different between the CEM3340 and AS3340. Without seeing your schematic I don’t know if your pulse output design would work with a CEM3340.

Where do you get your front panels made? They look like a fine job.

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I haven’t worked with a CEM3340 (I had one but I managed to fry the first time I tried to use it…) but I’ve observed the AS3340 works OK with pulse pulldown from 10k to 51k, faster fall time with lower values but not significantly and since the (CEM) datasheet suggests lower pulldown current is better I went with 51k (or actually a 33k+18k voltage divider). Sam’s 1222 schematic says


But if you wanted to use CEM and were concerned about it you could just change the 33k+18k to 6.8k and 3.3k.

Front panels from JLCPCB. They’re far from FPE but good enough for me.

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No one’s ordered any Sidekick PCBs yet, have they? Oh good.

I decided to add files to the Sidekick and Hero repos explaining how the circuits work. There’s always a risk in such an exercise of realizing you can’t explain a feature of the circuit because what the hell was I thinking? That happened with the Sidekick. The linear FM input made no damn sense. And when I went to correct that I discovered a previous fix did some unnoticed damage to the ground plane, so I took care of that too. Repos updated. I hope things are better now and not worse…

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Am I right to assume you won’t be able to wire a Hero up to act as a Sidekick?

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Right. The Hero sends CV sums to the header, the Sidekick takes header signals and feeds them into CV sums.

I presume you’re asking because you’re thinking you’d like a VCO that can be driven by a Hero but that has more inputs and controls then a Sidekick. One certainly could design such a thing. One could also use external mixers or attenuators to accomplish much the same. Put the PWM CV and a DC voltage into a mixer and send the output to a Sidekick’s PWM input to get both PWM CV and a manual pulse width control, for example. There isn’t a simple way to sync a Sidekick to anything but the controlling Hero, though.

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I suppose I’m thinking about versatility of the Hero/Sidekick system as a whole. But of course you’re right. There are more conventional ways to achieve the same object so the point is moot.

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Yep they are 3340a. Just confirmed.

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would these ever show up as Tindie items to buy possibly? Just asking for a friend

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I have some revised PCBs, I need to build a set to verify them. Then yes.

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you know I am always interested in adding to my analogoutput rack !

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Yeah, me too. tiny

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thanks alot , really would help out nd love the stuff I have bought from you before .

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thank you for sharing , really appreciate all the work you put into design and answering questions ! your pcb’s and face panels have been excellent and useful .

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So I see you have these on Tindie now, and yet I checked at Digikey and the dp3t switches are backordered til 12/22 so I saw Newark electronics has them in stock , just an update as 10/13/22 .

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Mouser has them too

and if need be you could leave the switch out until you can get one, it’ll just mean sync isn’t available. Ideally you’d add a jumper corresponding to the middle switch position but you could probably do without.

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thanks , I just couldnt get the number to evole these on Mouser so I went with Newark , but you are right , mine there wont be here til yikes 11/26/2023, wow long wait will go Mouser thanks Richard

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Thanks for this - just ordered with mouser - no waiting

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