Castle 000 + Castle 010 + Syntonie VU007B + Syntonie VU003B

Hi everyone, hope you are all doing well. I decided to start off my journey with these modules:
Castle 000
Castle 010
Syntonie VU007B
Syntonie VU003B

But I was wondering if this combination would work together, as I have read on this forum that the castle modules use a different sync input that the Syntonie VU007B. On the other hand I have also read that only one of the modules in the castle series needs to be synced. Sorry for the lack of knowledge as I admittedly did jump in head first with probably not enough knowledge although that’s what I tend to do with everything in life. I have searched around for answers but haven’t found anything. Any advice would be much appreciated. Thanks!


yes only the castle vco wants sync - and it’s ‘special’ in that it uses sync over the power bus - which is the same as 1st gen lzx

but you are not tied to the castle vco…

so just get any rca synced vcos - syntonie, lzx (gen2 onwards) etc


Ok great! Thanks for the info.

For the Castle VCO, you can also patch sync on the front panel if you have a 1/8” V or H sync output elsewhere in the system (but there aren’t many modern options for that either, unfortunately.)

1 Like

Hey @EuropeanBob :wave:t3:
Welcome to the video synth party :metal:t3:
Do you have some electronic music equipment or, better yet, some Eurorack modules​:control_knobs::loud_sound:?
If so, modulation signals can be used to modify parameters but there’s not a lot on the Castle 000 ADC and the 010 VCO. A second Castle Osc will go a long way, one for vertical bars & the other for Horizontal, then combine these with the Multi-Gate & Quadgate modules and your visuals will get interesting fast.

Are you planning to use a camera or video mixer to feed signals into the VU-003B?

Hi, thanks! I decided to cancel the 010 and I will use another oscillator from saytonie maybe. And yeah I will experiment with using a camera.

1 Like

I literally pulled the trigger on this same combo a month+ ago. I made an account just to share, almost done with the syntonie builds. Also, LM6172s are expensive. Audio circuits seem cheap in comparison, even when there’s a microcontroller involved.


Hi jmsiener hope you are doing well. Yeah if it weren’t for the LM6172s it wouldn’t have been that expensive for me. Could you post some updates in this topic on how your project is coming along? I might be able to learn a thing or two.

1 Like

Nice one that you’re getting the Syntonie Osc @EuropeanBob, I really like my one :slight_smile:

Welcome aboard @jmsiener & best of luck with your builds and respect for going down the DIY route :+1:
I’m actually building the 007B atm as well :slight_smile:
Yes, it’s frustrating that the LM6172 ICs have gone up in price but in fairness, many other ICs went up a lot more, factors of at least 2 if not way more. Hopefully 2023 will be looking much better. Petrol is maybe 15% cheaper here atm compared to a month ago & the highs since March/April. Hopefully 2023 will be a whole lot better for us all but especically for those in the Ukraine & those that were forced to leave there.

I did just see that thonk has the LM6172 for £5 whereas mouser was £6.73 or something like that. Also do you have the VU006 or VU009 oscillator.

I’m in the states and I found it much cheaper to order direct from Texas Instruments. It was around $5.50/chip and cheaper in quantity. Definitely $1 cheaper than Mouser/Digikey. Even at £5 that’s like $6.50 once I convert and pay shipping. Also, TI had an insane shipping turn around, had them in two days from ordering.

I suppose I’m going to have to get a couple of the Syntonie oscillators, I’m oscillator free at the moment.

1 Like

I thought I’d share my progress here. The castle builds so far have been super easy - all of the resistors are easy to place, pretty common components, and honestly not a lot to really worry about. As per any build both of the Syntonie modules are like 2 parts shy each from being completed and in general my cheap ass will need to buy more LM6172s. All in all really straightforward builds.


Not really sure where the answer is or the best place to ask the following but here we go:

I’m probably a month off from having these modules completed but I’m aware the Castle VCO needs sync and that sync on this module is received through the CV/Gate headers from the busboard. Does one bus expect to have horizontal and the other vertical sync? Which expects which? Horizontal of CV or vice versa and etc? On the RCA standard are the two mixed or modulated together to be extracted down the line? In order to implement sync with the VCO from a VU007b would there need to be some additional circuitry to make that happen? Is there something available for that application?

Thanks in advance, a lot of new to soak up here.

This is not 100% related to your questions but it’s been a helpful image for me when it comes to running sync through eurorack power. The images gets lost in the shuffle of websites over time so I’ve kept a reference copy on hand. Hope it may be of use to you or others



you can also sync it with the jack input on the front panel
and it is a lot of fun patching weird signals into that! (other vco’s, mixes etc)