ilovefuzz.com

I'm sitting on a BOM in my Mouser cart for this project: http://modularaddict.com/attachments/po ... lymoog.pdf

For all of the filter boards, C5 and C6 can be anywhere between 10-100uf capacitors so I'm trying to match values based off the C3 and C4 for the boards. Now, I know literally jack shit about electronics, I just follow BOMs and build the things. But instead of sticking 100uf across all 3 boards, I think it might be better to use different values for more pronounced filtering.

Does this make sense?
What I have in my cart now:
HP:
C3,C4: 2.7nf
C5,C6: 22uf

BP/BN:
C3,C4: 12nf
C5,C6: 47uf

LP:
C3,C4: 68nf
C5,C6: 100uf

Feel free to insult me.

I read everything in the build guide. There is actually no difference in sound from a 10uf or a 100uf output capacitor. It is best practice to buy them in bulk and keep them all the same. I noticed there is a mistake in the schematic where C5 is 220nF poly film. The PCB is marked correctly on the silkscreen you can see two polarized caps. 220nF would work but the PCB is not setup that way. I also noticed a small footprint on the PCB, for this reason I would suggest 10uf of a cheaper cap or 100uf of a more expensive 6mm panasonic part ECE-A1CKA101I

The relationship of the resistance and capacitance at the various circuit nodes are going to define the tuning (or, since I'm assuming you can sweep it the basic or center point) of the filter.

Here's a calculator that can assist: http://sim.okawa-denshi.jp/en/CRlowkeisan.htm

Now, since stuff like bandpass or notch filter is usually done by superimposing or cascade chaining your LP & HP, your tightest notch over the range of the filter will be when the two sections are built on the same starting point. My recommendation is to populate all the 10-100 stuff with the same value, it's just the value isn't especially critical. To do otherwise will just make response softer in certain modes (wider notch or bandpass window, that sort of thing). Though if you like to introduce variable results, you can switch in parallel caps to increase the value seen by the circuit at random node points.

eatyourguitar wrote:I read everything in the build guide. There is actually no difference in sound from a 10uf or a 100uf output capacitor.

Oh shit, these are outputs, huh? Yeah, ignore everything I just wrote, though that calculator can be instructive (and yes, I realize there are probably better ones elsewhere).

Thanks for the help guys, definitely what I needed to hear so I'll just pick up the 100uf Panasonic caps then that eatyourguitar recommended

eatyourguitar wrote:I read everything in the build guide. There is actually no difference in sound from a 10uf or a 100uf output capacitor. It is best practice to buy them in bulk and keep them all the same. I noticed there is a mistake in the schematic where C5 is 220nF poly film. The PCB is marked correctly on the silkscreen you can see two polarized caps. 220nF would work but the PCB is not setup that way. I also noticed a small footprint on the PCB, for this reason I would suggest 10uf of a cheaper cap or 100uf of a more expensive 6mm panasonic part ECE-A1CKA101I

The C5 you're talking about is on the Input/Output board which does use a 220nf poly film for C5.

The 220nf is to reduce noise on some fixed dc voltage follower. The voltage does not change if the cap is removed.