Cap value replacement for Zuul

[iamjackslackof]

Hi all,

Does anyone know if I can swap the 560nF film cap (C11) in the Zuul for a 470nF MLCC? I don't have a 560nF handy, and the footprint is pretty small for one as well.

Thanks!

 

[iamjackslackof]

I looked at using two 1uF caps in parallel, but couldn't get it to fit, so I just went with 470nF. Fingers crossed...

 

[swyse]

Caps in parallel add, so you would have had a 2uf cap if that had fit. If it isn't working as expected you can add a 100nf cap to your 470nf to get 570nf and that should be plenty close enough. I don't actually know what that part of the circuit does so I can't say for sure what differences you're going to hear, but it's part of the RMS detector circuit so if it doesn't seem like it's detecting the input right I'd check there.

 

[iamjackslackof]

Oops, I should have done 2 1uF in series then. But that still only gets me about 30nF more than my existing 470nF, so I'm gonna roll with it and see. Hopefully it doesn't matter much, or someone can chime in with it's exact role and if it will matter significantly. I did try a 100nF in parallel with the 470nF, but I didn't have enough room.

 

[Feral Feline]

Plenty of room!

I'd lay C4 (electrolytic) down so it's out of the way, then take the 100n and lay it over C12 and lay the 470n over C13 & C7 — the 100n&470n in parallel, both their legs bent 90º and down into the C11 pads, forming a "T" or umbrella over the other caps.

I'm sure 470n will be fine, even though I don't know enough about what it's doing.

PS: Another cheat I use, and it could work well for this PCB, is solder a/the component on the opposite side of the PCB. Works here, 'cause there's no pots or switches getting in the way.

PPS: Forgot there's also the SMD Zuul, checked that build doc and more or less the same Classic "cheats" will work for the SMD version.

 

[iamjackslackof]

My real problem was getting 2 caps to fit in one pad. I had small enough MLCC caps to fit in width, but couldn't get even their skinny legs two to a hole. Preliminary testing has worked with the 470nF though, waiting on my tuner/splitter to test the key functionality fully.

 

[Feral Feline]

I hear you. I've run across some small holes as well.

If need be, at a later date you could try getting a 100n soldered to the underbelly of this beast to get that 570n.

Curious, which version do you have, the Classic or SMD?

Good to hear prelims are going well.

 

[iamjackslackof]

I have the Classic I think, no SMD. I wasn't sure the difference, and the SMD scared me into getting the Classic lol.

And I think I will try to get a 100nF soldered on the bottom like you mentioned, it hadn't occurred to me before. Thanks for the tip and responses!