1 uf 7.2 x 3.5 box film capacitor
- Thread starter ac30irons
- Start date
I would avoid mlcc in the audio path of possible. If it's just power, use whatever.
Will a tall boy wima fit?
I’m in the UK and unfortunately we don’t have many great suppliers.
Where in circuit is the 1uf? You may be able to get by with something rated smaller with no change in functionality.
Also, bending the legs with needle nose, testing after bending, and mounting on the top side(pot side) could be an option.
The cap is actually taller also. I could potentially bend and lay on resistors !!!
Assuming we're talking about C6 and C9, I think you could get by with a 680nf there without issue. There's some filtering happening in the single Hz region but I think it's just a DC blocking cap for the clipping/feedback. Hopefully someone else can chime in who's more awake and confirm but I think you could debate without any audible effects.
Passinwind
Well-known member
How about this: https://www.taydaelectronics.com/wima-mks2-1uf-50v-10-polyester-film-box-type-capacitor.html ?
That's the smallest 1uF film cap I'm aware of, I buy them by the 100s from Mouser.
How the hell do you work this stuff out ? How do I even know if a cap sits in the audio path ?
The 50V Wimas are the ones I usually have to buy if I'm doing an Aion project and can't get away with folding over a Kemet.
(It's annoying tbh, so much so that I actually designed my own ODR-C-based PCB just so that I could use larger footprints for the 1uF and 2.2uF caps)
Will have to see if I can get them in the UK
Passinwind
Well-known member
Heh, I design most of my onboard preamp and pedal oriented PCBs specifically to leverage the smaller size of the 50V Wimas. I use the 1.5uF and 2.2uF ones quite a bit as well. I could see it being annoying if you don't already order stuff from Mouser all the time though!
Assuming you know basic component functions, I would recommend starting to learn how to do an AC analysis. You can pretty quickly deduct what is and isn't in the audio path. From there, you look for filters. 99% of the filters in pedals are RC filters. There are tons of calculators to work out the corner frequency.
If a large value cap is in circuit and it's not part of a filter, it's often a DC blocking cap. A 1uf+ cap won't block any audible frequencies outside of a filter. The small the cap it from the, the more low frequencies it will block. It's related to the time constant of the caps charge cycle. At certain values, AC looks like DC. Pay attention to input and output caps here but also in circuit.
So, in regards to C6 and C9, they're just DC blocking. A 680n will block some subharmonic stuff. Unless you're playing dubstep with a 5 string bass, you'll never tell the difference. Even at 220n, you'd likely not hear a difference on a standard tuned guitar. So, you can decrease/increase those caps as it suites you.
You can use them to "tighten up" the low end of a muddy circuit as well, though that's usually accomplished with the input cap.
There are advantages to using bigger caps. Assuming all your filtering is done, it can be a good idea to oversize the other caps. This gets into phase smear and "other" circuit resistances and is a whole other topic.
Ordering from Mouser isn’t the problem, the Kemets are still cheaper and just fine if you don’t need the smaller footprint (which is the case with Aion’s layouts, they’d still fit in a 125B just fine even with the extra millimeter of width)Heh, I design most of my onboard preamp and pedal oriented PCBs specifically to leverage the smaller size of the 50V Wimas. I use the 1.5uF and 2.2uF ones quite a bit as well. I could see it being annoying if you don't already order stuff from Mouser all the time though!
It’s like you’re speaking a foreign language. I have considered buying Brian Wamplers video course but it’s pretty expensive. I do need to learn this stuff !!!
Passinwind
Well-known member
Roger that, and something to think about if I ever do any more PCB layouts for DIYers. I‘ve had to kit up components for a number of friends in Europe, I also get how different the parts availability is over there.
Edit: Mouser does stock Kemet caps in that footprint too, at right at double the cost of the Wimas. Hard Pass!
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