Noise Reduction

Edit:

To be fair, I didn't properly address your actual point, which is more about hiss/noise within the AE Modular and my response below is more about noise external to the AE Modular. The response below stands as a response to the wider question; however, your problem could be more about joints on boards and/or connections. Taking some boards out, and maybe even moving them around to hear if the problem changes or disappears is worth a try. Also, does it disappear (or change) when you "earth" via an audio lead (if you have the headphone amp you can listen with and without the external audio connection).

The fact that touching some pots produces different effects suggests that it could be a board- or position-related issue.


Original Post:

I'll caveat this post with a note that I am no expert. However, having been forced to solve buzzing and humming on many occasions, in home studios and live, I have found a few things that work.

When we're interacting with the AE Modular we're really quite close to the electronics. We're also dealing with a system that uses non-conducting (i.e. non-shielding) cases and module front plates. Finally, the PSU isn't grounded (well, mine isn't). So, this means that the 0V (or "earth") reference is completely internal to the modular. So, when we connect it to something outside of its own world, there is every chance that the "earth" is not the same, hence voltage difference and current, which means buzz/hum. Even our fingers can represent an "earth" depending upon how we're connected to the world and various systems around us. That lack of shielding, and our physcial proximity to the electronics can all add up to hum generators getting close to electronics just waiting to pick it up.

There are many things to try to get rid of annoying buzz/hum. Sometimes one thing works well, sometimes it's a combination, and of course sometimes nothing seems to work. Here are a few things that have sorted me out nicely.

Before you start, try moving equipment around. It could be that you've put your AE Modular right next to a total hum generator, such as some lights, amps etc. Try also moving power cables for all pieces of nearby equipment around - remember to be listening all the time.

First, and this is simple, plug everything into the same socket/extension lead. It's amazing how effective this can be.

Second, try some different leads. It's amazing how what we think is a perfect lead (as it's brand new) is actually causing the problem.

Third, try putting something that breaks multiple ground connections between the AE Modular and your monitoring/recording - I have used many Behringer MICROHD Hum Destroyers (HD400), which is a pair of isolation transformers. OK, these really work for me, especially if you can connect with TRS leads to TRS connections on the other side (i.e. non-AE Modular) of the unit. I do use these between my mixer outputs and my audio card inputs and they immediately solve my noisy recordings. My audio interface has TRS inputs, so that works nicely. You can also use those ferrite chokes, which can be cheaper, I was just lucky with the transformers.

Running through those things fixes most problems and you can stop as soon as you fix it, which might cost you nothing. Personally, having one of those Behringer units  can get you out of almost any problem and if you're venturing on stage a DI box may also get you out of further trouble.