hey everyone. so i got the age old problem of tracking down unwanted noise in my audio chain. For the moment i can't figure out where it's coming from. I have a Metric Halo ULN-8 interface and a hackintosh with an Asus Hero X motherboard and Dynaudio monitors with an Adam sub. Only using quality balanced cables. The audio clips are all recorded directly from the audio interface recording panel.
The problem is twofold:
1. when the Kemper is powered off i have a slight but constant hum on the Main Outputs (i normalized the audio to 0dB so you might wanna turn down the volume before listening), sometimes it's louder than others, haven't figured out yet what trigeers it to be louder or not, it ranges from -75dB to -65dB and just to reitterate: this is with the Kemper powered off:
2. When the Kemper is on i get pretty nasty electrical interference noises, even with humbuckers there is a constant noisy clicking sound. I can minimize it by facing the guitar in a certain direction from the monitors. When i move and click the mouse (i use a wireless mouse) i can hear the noise changing/getting worse.
Here's the noise, in the beginning of the recording i'm facing the monitors and in the second half i turn the guitar 90° away from the monitors):
humbuckerhumdirectional.mp3.zip
Weirdly when i start recording in Cubase the noise gets worse, you can hear the noise changing/getting worse here when i start recording at aroun 8 seconds in:
Strangely enough, when i start recording in Cubase despite the worsening noise, the noise changes when clicking the mouse is gone. When i stop recording in Cubase i can hear the noise chanbging when clicking the mouse again.
I tried pluging in the Kemper into different power outlets of my place but the problem is exactly the same with all outlets. I also tried connecting the Kemper to a power filter (not a high end Furman though, just a basic APC). I am using balanced cables throughout, balanced from Kemper to Audio interface, balanced from Audio interface to Monitors, balanced from monitors to Subwoofer.
The problems also persist when i unplug the USB from the Kemper (which i normally keep connected for rig manager). Also tried plugin the computer and audio interface into different power outlets of my place in various combinations with no luck.
Not sure which steps to take next, i'm tempted to get a Furman to see if that solves anything but not sure if it would help. Tried googling around and although there's many threads around none really helped so far.
Btw i live in a very old building and although i don't have any obvious electrical problems and enough Ampere on the circuit i do get the lights flickering when i turn on the vacuum cleaner. I also see voulme spikes in the Kemper channels when switching on/off any electrical devices or lights in the flat (again even with the Kemper powered off), the spikes are much higher when i switch on/off my pedal board power suply and desklamp which are on the same circuit than the Kemper but i do get visible spikes when switching on/off any device in the flat. Not sure if that's related but probably is. Getting an electrician in here to check and sort out the power circuit in my place would be really expensive so i'm holding off on that for the moment. Maybe there is another solution and a high end Furman would fix it ?
Any ideas ?
