Capacitor selection and exchange

[DailyDovetails]

I am curious about a few capacitor exchanges and the reasons for doing or not doing them and wanted to get some opinions. For a 1u capacitor like C13(Non-polarized) in the kewpie fuzz https://docs.pedalpcb.com/project/KewpieFuzz-PedalPCB.pdf or C11 in the Pestle distortion https://docs.pedalpcb.com/project/PestleDistortion-PedalPCB.pdf is there any reason to use an electrolytic capacitor over say a polyester film or even a MLCC? Then say in the Pestle on C4 is there any reason to use an electrolytic over a MLCC rated for 10u? I get the use of electrolytics for power filtering and in sizes above 10u but I'm wondering if when I run across these in a circuit if there is ever a reason to use an electrolytic outside the power section.

Does it make a difference if the electrolytic goes to positive or ground like C10 in the Kliche mini SE? https://docs.pedalpcb.com/project/KlicheMiniSE-PedalPCB.pdf

Let me know what your thoughts are on this.

 

[Cybercow]

Outside of power conditioning/control, I've not encountered any issues using up to 10µF MLCC in place of electrolytic capacitors. Depending on circuit location for any specific alternative use of MLCC for an electrolytic cap, the worse I anticipate happening is the possibility of parasitic microphonic feedback. Socket & see.

 

[JTEX]

The two main things to watch out for in MLCCs in the audio path are microphonics and capacitance loss (possibly huge!) with applied DC bias. The first is only really a potential issue when used around the input stage in high gain circuits. The second can be mitigated by overspeccing the cap's rated voltage (say, use a 50V cap if it has a 5VDC bias across). Also, larger physical sizes do better in this respect than miniaturized ones.

 

[DailyDovetails]

Outside of power conditioning/control, I've not encountered any issues using up to 10µF MLCC in place of electrolytic capacitors. Depending on circuit location for any specific alternative use of MLCC for an electrolytic cap, the worse I anticipate happening is the possibility of parasitic microphonic feedback. Socket & see.

That is kind of what I was hoping. Not that I have a particular preference for one or the other. I got a DE-5000 LCR for Christmas and I'm realizing of the caps I have the Polyester films are by far the most consistent and have the lowest DF across the widest range of frequency followed by the MLCC and then the electrolytics. This is purely anecdotal based on what I have and might not be universally true.

The two main things to watch out for in MLCCs in the audio path are microphonics and capacitance loss (possibly huge!) with applied DC bias. The first is only really a potential issue when used around the input stage in high gain circuits. The second can be mitigated by overspeccing the cap's rated voltage (say, use a 50V cap if it has a 5VDC bias across). Also, larger physical sizes do better in this respect than miniaturized ones.

That's good to hear. I have a few rack mounts that I run my guitar into from a mixer one of them recently started misbehaving so I replaced all the ceramic caps with MLCC and got it mostly working, then replaced the 1UF electrolytics with poly film and got it working the best it has since I have owned it. The electrolytics in it are made by Matsushita and are apparently prone to failure so I thought while I was in there I would do the rest. so I will do the few 1.5 uF with Polyester and then do the 10 uF with MLCC and anything larger I will use electrolytics again. I believe everything in this will be under 9 volts but will multimeter it just to be sure. I found this chart which I believe represents what you were saying about over sizing the MLCC and it looks like the X7R line would be a good choice here.

Thank you both for the support. I guess I need to investigate the micro phonic aspect of this a bit more but I feel comfortable starting on the rest. Worst case I pull some MLCC and put Electrolytics back.