Axial Capacitors

[Zanius]

Lately I'm into axial oversized capacitors. I guess I'm not the only one ever gone through that phase.

I'm not gonna talk about electrolytic ones, but about non-polarized in the "nF" area.
I got plenty different models and most of them don't seem to have any markings. But some of them do.




You can see the black line on the middle one, does it point to cathode?
And on the two others, the one is clear on one side and blue on the other. The second is black on the one side and red on the other.

I'm trying to use them wherever there is enough space and most of the time they work fine. But the second a circuit doesn't work I can't get it off my mind that the may be of blame. Is this something I should look out for when installing?

[Beaker]

When I started putting NOS axial caps in guitars, I came across the same issue.

Those caps are not polarised, so does not matter which way around you put them.

Some old paper in oil caps have a stripe on one end - like your middle one. Even though it is not polarised, the stripe is best put towards ground. It's something to do with the way they were constructed, and mounting them the right way round, made them last longer in use. I don't know why - I've never come across an explanation for this.

Maybe the blue/red is a similar marking?

I suspect it won't make a blind bit of difference in a pedal at 9V, but probably will if you run it near it's maximum voltage rating.

However, as they are not  polarised, it will still work fine if you mount it "backwards".

In other words mount as if it were polarised, with the stripe showing the negative end - even though it doesn't!

Confused - I am!

[Beaker]

I've just found this, that seems to confirm what I said above:

https://www.ifixit.com/Wiki/Troubleshhoting_logic_board_components

[Zanius]

Thanx Beaker! Good to know.
I tried in general to "go with the flow" but not every layout comes with a schematic and my knowledge is fairly poor, so most of the times it's 50/50 for me.  

Whenever things go wrong it is easy to blame the less acquainted-with factor :)
The unforgiving truth is mostly the same though - User error!

[Travis]

What's your opinion when using them with "positive ground" Beaker? I would think that the stripe would go to the more negative voltage, rather than ground in those cases. But that's just what I've been guessing.

What makes it more confusing is that some have a red end rather than a stripe. In this case this is the anode on the polarized caps that I have. Easy to get that mixed up if you're used to seeing the mark as an indicator of the cathode. My guess is that when it's red it's the anode, some are purple etc and it's confusing.

[Beaker]

Honestly Travis, I really don't know for sure what the score is with these, so can't help much more with this. I have never used NOS axial caps in any of my pedal builds, so my direct experience is limited solely to sticking them in guitars.

I think your assumption about positive ground is probably correct - but I don't know for sure.

Maybe I just haven't been looking in the right places, but I really can't find much info on this at all.

All manner of different markings and colouring schemes seem to have been used in the past, so yeah, it really is confusing!