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PC Sound card noise from CPU

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ELS122:
I have pretty annoying static picked up by my sound card, most likely from the power rail, that directly corresponds to the coil whine from the CPU chokes.
the setup is as follows:
AMD A10-7870k CPU
ESI ESP 1010 Sound card
FSP power supply
MSI A68HM-P33 V2 motherboard
GTX 950 graphics card

I tried swapping the PSU for a more expensive Corsair power supply and to my surprise the noise was much worse, swapped back to the FSP cheapo and it was a only mild as was before.
but it's still annoying.
I tried underclocking the CPU but it didn't change the noise.
I tried underclocking the GPU, thinking that maybe there was some filter chokes for the PCIe slots near the CPU and that I was hearing those, but no, didn't change the noise either.

I was thinking of getting a PCI slot extender for the sound card and splicing some filter circuit on the 5V power rail, what do you think?
and also, would it be the 5V power rail? if it's coming from the CPU it would make me think that it would be the 3.3V rail instead, but what would a sound card need 3.3V for?
but the fact that the 12V phantom power for the mic inputs has the same noise on it would make me suspect the 12V rail, which would also feature a -12V rail, ideal for some opamps probably.
also that noise is present on the output too, no matter what the volume is set to in the software control panel.

wraper:
You could play with power saving features in BIOS. Always keeping CPU clock at maximum often fixes the issue but increases power consumption. The best way to get rid of this is changing the motherboard to something else but you never know if it will not have the same issue. Another option which worked for me well is making 1-2 turns of audio cable through a ferrite ring.

RoGeorge:
The CPU has it's own SMPS onboard, on the motherboard, right near the CPU.  Usually more than one channel, easy to spot by the ferrite cores and electrolytic capacitors surrounding the CPU (being close to the CPU and SMPS MOSFETs they also work at high temperatures).  Most probably those capacitors have dried with time.

I'll try replacing the motherboard with a better model and sell the old one.  Replacing the capacitors is usually tricky, and not guaranteed to work if the MB has a bad design.

From BIOS, try enabling "spread spectrum" if there is any, might help.

wraper:

--- Quote from: RoGeorge on September 17, 2022, 11:17:12 am ---Most probably those capacitors have dried with time.

--- End quote ---
Then you usually will get system instability. IME a lot of motherboards, especially older ones like OP has are just garbage in this regard straight out of the box. In the end I fixed it in the root, I use optical audio out for about a decade.

ELS122:
but if the sound card has bad power supply noise rejection then imo its the sound cards fault as much as any.
I inspected the sound card and it seems theres a +5V, -5V, +9V, -9V, +3.3V, and VCC rail which connects to 5V on the PCI slot.
I dont get where its getting the negative supply from, +12 and -12V pins dont go anywhere. +I/O does go somewhere, trough a ferrite bead.

theres a 7809 and 7909 regulator on the back. no other regulators i'd recognize but Ill check some part numbers

the board has 21 JRC4580 dual op amps, 3 HC4053A multiplexers, a single XWM8816 digital volume control, a AK4358VQ DAC, a AK4114VQ DAC
thats about all for the analog stuff

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