help with FAST / WAW setup

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Founder of XSA-Labs
Joined 2012
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Ground loops from a PC can be a problem that is hard to get rid of. I tend to use laptops and when in total fruistration, I run on batteries and disconnect from mains.

Try to not connect ground shell of 3.5mm or RCA jacks to earth/chassis GND directly. They should be connected to just signal GND on PCBs. PCB signal GND (clean ground) should be connected to Earth/chassis GND (Dirty gorund) via a 10R (ground loop breaker) resistor. Add back to back diodes in parallel for safety. There is a nice whitepaper here on tricks:

Audio Component Grounding and Interconnection

Grounding and Shielding for your DIY Audio Projects
 
Ground loops from a PC can be a problem that is hard to get rid of. I tend to use laptops and when in total fruistration, I run on batteries and disconnect from mains.

Try to not connect ground shell of 3.5mm or RCA jacks to earth/chassis GND directly. They should be connected to just signal GND on PCBs. PCB signal GND (clean ground) should be connected to Earth/chassis GND (Dirty gorund) via a 10R (ground loop breaker) resistor. Add back to back diodes in parallel for safety. There is a nice whitepaper here on tricks:

Audio Component Grounding and Interconnection

Grounding and Shielding for your DIY Audio Projects


Thank you! I have been searching and searching for articles like the two you linked even before I ordered my boards. This gives me a pretty nicely itemized list of things to do and the order in which I should try them. I will check back in when I have success or lack of success to report.
 
Ok first check on the itemized list was the one I thought was the most likely to work and indeed it did!

The biggest problem with what I was doing was providing a separate ground path to the XO board for each channel. by combining these ground paths for input, low out, and high out respectively the buzz is totally gone. This makes me super happy!

Now I need to put my active xo project in a plastic box. I'm going to draw a box for it and have my bud 3d print it. I plan on leaving this project as a floating ground. I don't see anything wrong with that unless you all want to talk me out of it. Using a plastic box I don't see much merit in a safety ground. I guess the RCA ground could become hot?

Next part of my project is testing the response with software and a mic. I would love direction to any resources you guys have used on this topic. In the mean time I'll be looking into that myself.

Thanks guys I certainly wouldn't have gotten this far without your guidance!
 
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