Onboard audio LEDs

Gas_Mask_ · April 23, 2020

I apologise if this has been asked before, but I couldn't find anything by poking around.

Do the LEDs on a lot of motherboards that outline the "separated" bit of the PCB for audio actually do anything to help the separation or are they purely for looks? Moreover, if so, would turning them off have a significant effect?

Thanks in advance

-rascal- · April 23, 2020

4 minutes ago, Gas_Mask_ said:

I apologise if this has been asked before, but I couldn't find anything by poking around.

Do the LEDs on a lot of motherboards that outline the "separated" bit of the PCB for audio actually do anything to help the separation or are they purely for looks? Moreover, if so, would turning them off have a significant effect?

Thanks in advance

The LED separation is mainly for looks.

Depends on the motherboard, that LED strip *can* be disabled / turned off within the BIOS settings.

Gas_Mask_ · April 25, 2020

On 4/23/2020 at 4:11 AM, -rascal- said:

The LED separation is mainly for looks.

Depends on the motherboard, that LED strip *can* be disabled / turned off within the BIOS settings.

I wasn't worried about if they could be tuned off or not, I figured out how to do that. I was just mainly curious if they have any effect on the sound or the electrical signaling.

The Flying Sloth · April 25, 2020

They have 0 effect, they're just there to look pretty.

Sloth

-rascal- · April 25, 2020

1 hour ago, Gas_Mask_ said:

I wasn't worried about if they could be tuned off or not, I figured out how to do that. I was just mainly curious if they have any effect on the sound or the electrical signaling.

A bit of physical separation on the board will help...a little bit.

All the thousands of traces in the different layers on a motherboard crossing each other will certainly cause some electrical interference.

In addition to physical separate, you would IDEALLY also want to have some kind of metal shielding.

Some boards actually have this.

If you disassembly a laptop, because the it is so compact, in some cases, you can see a metal shield over the:

Bluetooth modules
WiFi modules
USB controller (?)
Over certain chipsets / SoCs

For an example, Gigabyte has a EMI shield over the audio SoC on their higher end Z390 boards.

Same goes for ASUS on their ROG boards, and AsRock as well..etc, etc.

artuc · April 25, 2020

Yeah as @-rascal- said.

If the LEDs are illuminating an actual circuit board design like an isolated ground plane they don't help at all directly but may be illuminating something that does.

The layout can be very important, electrically they can be the 'same' as in what a wiring diagram shows.

Like say with a DAC. IIRC digital and analog circuits should have seperate ground planes bonded with a small trace.

A circuit diagram may not show this and technically you could do say one big ground plane or thin traces with complicated long routing, but there can be measurable performance improvements from good routing and layout.

Going way back for a real world example I think they redesigned the Millet tube amp power supply ground plane in a revision and got much better measurements on the power supply.

It's a dark art and insanely complex subject.