what is that noise?

[massatony]

Okay, so I've built around a 100 pedals, with the majority working as intended. The problem I have is that many have a rattily  sound.... something like a not quite right speaker. The sound is not overly loud however is annoying and I would dearly like to know what causes it.
The amps are fine and are not the problem.
Any help would be appreciated.

[Bio77]

What about your power source for the pedals? 

[mauman]

Can you talk about the conditions when it's there, and when it's not?
- bypass vs. active?
- high vs. low volume setting on the pedal?
- high vs. low input level from the guitar/other pedals?
- high vs. low gain setting on the pedal?  etc

[matmosphere]

I always try to make sure stuff like that isn't caused by the wiring in my house or some lighting or something like that.

Try setting up in a different room, or see if it happens at somebody else's house. Unplug everything and try stuff one pedal at a time, see if it's inherent to a single pedal or if it only happens when things are chained together.

[massatony]

It happens regardless whether that pedal is in a chain or not. I am aware of ground loop and have ensured that all gear used works off the same GPO.

[massatony]

 bypass vs. active?                                                                     Only on active
- high vs. low volume setting on the pedal?                                  Doesn't matter
- high vs. low input level from the guitar/other pedals?                  ditto
- high vs. low gain setting on the pedal?  etc                                 Ditto

The mystery is that it only happens with some pedals. If a "good' pedal is chained with "bad" pedal. the noise is there unless the "bad" pedal is bypassed.

[massatony]

Well the power source works fine with other pedals. Although i was considering including a simple power filter to the circuits which are problematic.... and see what happns.

[mauman]

I think we might need to hear the noise.  Can you post something here, Soundcloud or YouTube?