Tips for resolving ground loop noise.
Tips for resolving ground loop noise.
Thanks for your update. I understand you're looking for advice, especially since you're not very experienced with multimeters and what to check. I’d really appreciate some help if this comes up.
I’m hoping the isolator will work out of the box. If not, at least it’s a reasonably affordable option, so I’m okay holding onto it until then. It would be better to spend around £8-9 on something that actually functions than £60-100 for nothing.
Also, both the speakers and the sound card are old models from the 90s—Yamaha. I’m hoping there won’t be any compatibility problems with their pin setups. 🤞
The isolator has arrived. I'll test it later and let you know if it resolves the problem.
Sadly, it hasn't worked.
🙁
However, I have discovered, that it's dependent on the sound card I'm using. One thing I didn't share is that my retro rig has two sound cards - one ISA, a Yamaha, and one PCI Sound Blaster. The latter is for redbook audio CDs/games.
The buzzing happens when the subwoofer is connected to the Yamaha. It stops/doesn't happen if it's plugged into the Sound Blaster. Again, can't say I ever noticed that before. So I'm not sure if it's a recent thing or not.
EDIT: Okay, to be more specific, it's the Mic port on the Yamaha that causes it to buzz. It might be a bit faulty...? I also suspect the names on the ports are labelled wrong, but I'm not 100% as it was bought second-hand. But the subwoofer/speakers should be going into Audio In/Out, but nothing can be heard. It only works if it's plugged into Mic.
Two sound cards could easily form a loop based on the ports, devices, plug types in use.
Consider the audio input/output locations—front, back, external?—and whether port and plug colors are standardized.
Determine if the port is on the I/O panel or a case connection (front, top). A misconnection from the motherboard to the case might occur, leading to confusing wiring and inaccurate documentation.
The connection cables may also not match the expected specifications.
Refer to the motherboard’s User Guide or Manual for guidance.
Attempt a simpler configuration, disable the Yamaha card first, test, and only remove it if disabling stops the issue.
It may be tempting to keep using the Mic port, especially if it seems functional, but this doesn’t guarantee a resolution.
I’ll consult the resident audiophiles regarding any potential risks of keeping the Mic port active.
It's the back I/O port. And unfortunately they're not colour coded, unlike the PCI Sound Blaster. They're all black. There's Game Port, Mic, Line-in, and Audio In/Out. My Roland SC-55 is connected to the game port with an adapter I bought and a green 3.5mm jack is in the Line-In.
This is the motherboard in question:
https://theretroweb.com/motherboards/s/abit-ab-be6-ii
The only misconnection I discovered last night was that the PC speakers weren't plugged in right from after I'd set everything up the first time, but that's sorted now.
I can try looking taking both cards out and testing the Yamaha on its own.