Cadet/Castle components sources and substitutions

Hi all -

I feel a bit silly asking this question but I am new to eurorack modules and building any sort of DIY video module. Just making sure i get my head around whats what, before i buy parts for cadet 1-3…

I have experience designing and fabricating boards for LED control and other applications - so not a parts noob, but here i am.

the futurlec parts - specifically:


seem like there could be an easy sub from mouser - so i ask: why specifically them?

also the thonk parts? - there is no reccomended US vendor (seems like BLMS could have the knobs??)?

just trying to optimize purchasing.



Hi @dubpixel. Your question seems perfectly reasonable to me. I don’t see any reason to be fussy with those connectors - it’s probably just coincidence that LZX bought a large batch of those parts from Futurelec at some point in the past so that’s what ended up listed in the BOMs. They are completely commonplace and any sensible substitute is likely to be just fine.

The Thonk pots and knobs are a bit different though. The trouble is that the manufacturers of those things offer the parts in thousands of customisable varieties, with minimum quantities well into the thousands and price points that are only good in the hundreds of thousands. So there are usually only a few variants that are stocked by any reseller company that low volume purchasers can choose from. Thonk happen to stock a range that are really convenient for DIY use and very reliable, and they are geared up to handle low volume customers, so it makes a lot of sense to use them for those parts. I guess LZX could have designed their DIY cadet boards for the varieties readily available at one of the big electronics resellers, but honestly I think the Thonk choice was a good one.

Personally, I use knobs from various places. That’s one thing you can happily vary to your heart’s content. Just make sure your choice matches the shaft of the pot, and be aware that some knobs with large skirts won’t fit the modules.

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you can also search for 9mm rightangled pots in other places, if you like to hunt for cheap.
they might not have the same quality as the Alpha pots Thonk uses,
but still good enough for your use.

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I’ve been compilling a mouser BOM for the full Castle series (1 of each module) and mouser indicates that some parts are reaching their end of life and some have already done so, the website claiming they are obsolete.

One such example is the Metal Film Resistors - Through Hole 100Kohms 1% 100PPM. But in this case they indicate the corresponding substitute.

The same does not happen with the Multilayer Ceramic Capacitors MLCC - Leaded 0.1uF 50volts C0G +/-5% which is “Not recommended for new designs” and does not have a matching alternative.

The 1N4001 Rectifiers Vr/50V Io/1A T/R is also obsolete. No substitute is suggested by Mouser.

Could someone help me substitute these last two items? I understand they are somewhat simple components but I’m not that knowledgeable about this and would like to avoid wrong decisions.

There are other items nearing their end of life (as stated by mouser) but as they still had stock I did not write which. If I find the time I’ll revise the list and take note of all of these occurrences.

Thanks for your help!

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mouser’s substitution suggestions are not always 100% - I suggest that you actually search for yourself on mouser for similar items - just check that the specs are the same or very similar, if in doubt check back here

Both 0.1uF (100nF) 50v c0G 5% tolerance multi layer ceramic capacitors and 1N4001s should be easily available at mouser, they are really common


here’s a selection of N4001s|0&qty=100

and here are the caps

but learning how to search in mouser and tayda and thonk etc etc is part of the skillset required for diy, especially for things that are EOLed, 90% of the time there is an exact replacement available


Souka, would you mind sharing those BOMs? I need to go through that same process for myself soon.

@Agawell you are correct, I should invest in learning more on the BOM creation part. Thanks for the advice and for the substitutes :wink: I appreciate it.

@Jefro I’ll share it. Just want to go over it once again to verify and clean it up a little. I’ll probably create a whole new post for that but I’ll let you know through here.

Edit — adding the Mouser BOM list.

@Jefro here are the files. If you can, double check everything.

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I just rolled with it and placed the mouser order for the full set. I did see a capacitor that was not available but it was all alone on the Bom and there were others of the same value. I just deleted it from the cart before placing my order. We’ll find out if I screwed up by doing that. One thing to note is that I’m not building the quad gate, so may not notice a few missing/wrong parts. I think I may have also removed a toggle switch that was unavailable, but I can get a good replacement locally.

My order just got here, so I’ll follow up soon.

That cap that was unavailable at mouser turned out to be c14 on the Clock VCO. ( The 2nd module I built last night.) I used one of the other 0.1uf caps in place of it, assuming there would be one in the extra parts due to not building the Quad Gate. The Clock VCO I built works, but I don’t know how this cap will effect behavior.

Which cap did you replace with which cap???
often they are dictated by what is either available or cheapest at the time of writing the BOM - caps or resistors of the same value/type can almost always be substtiuted without issue

C14 on the clock VCO was swapped out with one of the other 0.1uf caps. The clock VCO cap was a C0G type, the one I replaced it with is a Z5U type.

For the time being, I just made the cap easy to spot so I can replace it with one more suitable, if need be.…-a-concise-guide-to-ceramic-capacitor-types/

I suspect you will be fine - there might be a little bit of noise introduced though

There’s some noise when I’ve got it in horizontal mode for sure, less so with vertical. It should probably be replaced in the BOM as the part in the BOM is obsolete.

hmmm, maybe but substitution’s an important skill to learn as is wokring out that, for example 0.1Uf is 100nF and 0.1nF is 100pF

it’s pretty easy

a good idea is to buy 100 of any common caps/resistors - I’ve got loads of 0.1Uf (100nF) C0G caps - they are ubiquitous - almost all synth DIY uses them

but individual part numbers come and go, as manufacturers update their lines from time to time

Of course, but since the idea was to do that legwork here for others, it’s important that I call it out.

the problem with that - and why people generally just leave the original BOM as is a lot - is that these things change with no warning - the newly substituted part is discontinued and replaced and then the BOM needs updating and repeats the cycle with another component and another and another

And at that time the next person can do the swap themselves. Why so defensive about it? I’m just trying to help save some folks a little time. I could have just said yep, the Bom is good, or said nothing. But I made a promise to follow up if I saw issues, so that’s what I did. I’m not here for an argument.

Sorry wasn’t trying to be defensive or start an argument
Actually I think it’s a great idea :+1:

This Coronavirus thing has got me all wrapped up in my own head, I’m sure I’m not alone in that. So yeah, apologies if I got a bit out of line.

Anyway, now if someone follows the posts, maybe they’ll learn something about substituting caps, without doing it the hard way like me. :sunglasses: