Styroflex caps for Shuthri filter


would these caps be alright to use for the 4 filter caps

thanks in advance

They look fine. I used similar ones from ebay … they need to sit upright on the PCB, slightly tilted, but that is OK.

Like this:

nice, I will order those then :slight_smile:

This might be a stupid question, but why is it alright that they seem to be completely different spec to the little red ones that came in the kit?

Lots of different types, even for the same capacitance !

I know there is lots of types, but I was just concerned the capacitance of the styroflex caps seems way different to the film caps, but I will stick them in and see what happens :smiley:

Ah, you’re right: there are 220 nF capacitors on the board, but you were talking about the 4x 1nF ones …

I used 1nF styroflex caps on the picture I showed, of course …

Sorry for the confusion !

These are the ones I got (still available !)

Amazing, your ebay fu is way better than mine! I couldn’t turn up anything. Thanks so much :slight_smile:

I can’t wait for all my bits to arrive to mod this shuthri, going to do all the mods in the wiki hopefully over the weekend, it will be awesome.

So don’t use the 220nF instead of the 1nF ones - you could use them for C15 and C19 (but that would be overkill).

Have been too busy at work to order any yet, but will deffo order the right ones :slight_smile: thanks for your help bro.

The styroflex caps on the 4pm board are specified to have a 5% tolerance. Going by the markings on the caps in the picture on ebay, those look like 10% tolerance caps. Those capacitors are in the filter, and that’s one place where it’s important that the capacitors are all pretty closely matched. Tolerances are important there. It would probably be better to use caps with a tighter tolerance.

So would it be better to get some 1% film capacitors?

I think the consensus is that 5% tolerances are good enough, but there’d be no harm in using 1%. The parts in the filter circuits are one of the places where tolerances are important - you want to make sure filter parts meet the specified tolerances, but there’s apparently not much to be gained by exceeding the specified tolerances there. Here’s some more detailed info on part tolerances from people who know more about this stuff than I do:

You can substitute parts a lot more freely in other parts of the build - the tolerances on the control board doesn’t matter as much, for example, but the filter circuits work better if they are closely matched.

In the 4pm there are four filter circuits. As I understand it, they interact with each other, and will produce the best results if they are closely matched (as close to the same capacitances, resistances, etc. as possible). Parts like capacitors and resistors vary a bit from piece to piece, but tight tolerance parts vary less - you might get lucky and pick matching parts even with loose tolerances (or you could manually check each part with a multimeter and choose the closest matching parts), but you’re more likely to get matching circuits if you use tighter tolerance parts. The design expects four identical filter circuits - if the parts in the four filters are not closely matched, the filter processing won’t work as well.

You can look at the schematics to figure out which parts are in the filter circuits. Those parts should be closely matched.

…also worth noting that some of the parts from no-name suppliers on ebay (chinese sources, etc.) are counterfeit parts with mislabelled tolerances, factory rejects, carbon resistors painted to look like metal film, etc. - it’s worth testing those parts with a multimeter every once in a while to make sure they’re within the stated tolerances.

borfo, the 220 nF ones on ebay (link in the first post) are 10%, but the correct ones I linked to (the 1nF ones) are 2.5%, so these should be fine.

They (the 1nF 2.5% ones) work really well in my build …

Oh, right… I didn’t see the second link. 2.5% should be fine.

I jump on this thread as a capacitor noob.
I have a some lots of plastic film caps (like these ).
I was just wondering if I can use them for building shruthis (filter and control board).
What should I be aware of ? What is exactly the difference with ceramic or electrolytic ones?

(Sorry again for being so noob, I read some stuff online, but the answers are a bit elusive as it depends on what you are building and your needs)

If your caps are the right capacitance and the right tolerance, and they are rated for the voltage for the caps specified in the Shruthi BOM, you could probably use them in the filter sections of the shruthi. I don’t think the tolerances matter too much on the control board - as long as the capacitance rating is right you should be able to use them, but ceramic caps are cheap and easy to find so there’s probably no point in using metallized film/foil caps there.

> What is exactly the difference with ceramic or electrolytic ones?

Electrolytic capacitors are generally polarized, and ceramic ones are typically not polarized, so you generally can’t substitute them. That’s one difference, anyway.

Here’s a quick overview of capacitor types:

Thanks @borfo

Clear enough, thanks for the link!

I realise why I was confused about values now! here the guy talks about putting 220p in his filter section (these

I have ordered the ones linked above by eelco!

Ah, now it’s my turn to be confused again :slight_smile:

The guy you link to built a 4-pole mission filter board, which has 220pF caps. The one I showed is the ‘standard’ SMR4-mkII filter board, which has 1nF caps (but also has four poles, of course) …

Which one are you building ?

The same guy that sells the 1nF styroflex caps also sells the 220pF ones:

Maybe send him a quick e-mail in case you are actually building a 4-pole mission filter board …

If all fails I might have some left.