4-Pole Mission Substitute Components

Hehe, stuck with uzebox resistors (1.58K, 3.16K, 806, 562, and 301Ohm)
Ordered a bunch of 5% with closest values. Hope i’ll be lucky.

Ok then sorry if this is a bit off-topic, is this distinction the same about the svf board?
I saw that it the BOM, from different providers you mixed 33.0k and 33.2k 1% resistors. I guess i better pick them all as 33.2k?

On the SVF, whether it’s 33k or 33.2k is not critical. What is more critical if you really want to be an audio snob is whether the values are matched. If you tolerate a -60dB “bleed” on your HPF when the cutoff is set to the max, you’re fine with unmatched values.

I have managed to order all of the parts from Mouser, except the 220uF ceramic capacitor (C30) - which is out of stock. I’d hoped to be able to get this locally, but 2.5mm pitch capacitors of this value seem to be rare! Does it have to be ceramic?

It’s 220nF, not 220uF!

Oops! That’s much easier to find. I’ll go and hide in the corner now… Thanks pichenettes!

@toneburst: Where will you be using the Y5U caps? It’s probably best to always keep NPO/COG type ceramics within the audio path as other ceramic types (X7R, Z5U, Y5U) can distort the signal unless you’re just using them for stabilisation or power bypassing.

Also if you want to “gold-plate” the design, the Farnell code for 1% 220pF styroflex is 9520716.

@gwaidan thanks for the tips. The Y5v caps were these 220nF ones and these 100nF ones . I don’t honestly know if they’re used in the audio path.

Sh*t! Just realised they’re also 5.0, rather than 2.5mm pitch… they won’t fit… :frowning:
Doesn’t look like I’ll be finishing this project over the weekend, afterall…


There’s two pitches on the board for the 220nf. It may fit in the outer hole. You can make it fit with some leg bending, but at the expense of neatness.

Aaaaaand the 220nF 2.5mm-pitch ones are out of stock… :frowning:


@6581punk it’s the 17x 100nF that are the problem though. It’ll look shit if I have to bend the legs on all of those, although if they’re no wider than the 2.5mm ones, they might be able to be made to fit, looking at the circuit diagram.


I have a full set spare 100nf if you want them. I have quite a few parts from the saved basket available as I had already got a big stock of parts, but having a minimum order to fulfil I grabbed pretty much everything.

@6581punk wow, if you could spare some, that would be excellent! How much do you want for them + postage? You’re in the UK too, aren’t you? Also (and I’m being cheeky here, I know) but if you also have a spare 2.5mm-pitch 22nF one, that would be super-cool. These things cost peanuts to buy from Rapid, but the postage always seems extortionate.

Actually, I just realised I paid extra for next-day delivery when I placed the order on Wednesday, and they’re still not here…


Are you in the UK then? postage and cost doesn’t really matter, it’s only pence.

Having looked through my rather badly organised stock control system (the floor and cardboard boxes) I have the following:

25 x 100nf.
2 x100pf.
2 x 18pf (control board).

Oh and the tantalum for the PSU section.

Now that I know you guys are in the UK, I will read your posts with an English accent. I hope you will read mine with an American accent with all of my haRRRRd RRRRRRRs :slight_smile:

randy909 lol sure thing ;)6581punk Yep, I’m in London, in fact. If I take 17x 100nF, will that leave you enough for your own projects? I think I have all the rest, or will have when these Farnell and Rapid orders turn up. Thanks again, I owe you one!


Okay doke. Post your email and we’ll sort it out via email.

@pichenettes any comments on the NPO/Y5v issue gwaidan mentioned? 6581Punk has kindly donated some 100nF caps (thanks again!), but I still only have Y5v 220nF ones. Will one of those be OK at C30 on the 4-Pole Mission filter, do you think?


Yes it’ll be alright.

@pichenettes Cool. Sorry for all the questions. I did try and trace on the circuit board, but I couldn’t tell if that particular cap was part of the audio path or not.