Do you know the capacitors function on this motherboard

[johhnn]

Hi. I have the asus H170I-PRO motherboard, which has 4 gold coloured capacitors in the corner. These are described as audio grade premium caps by the manufacturer. But what do they do. I thought they may be to smooth the dc power supply a little but they are far away from the audio chip. Or are they dc blocking caps. Do you know.
Many thanks.
https://www.google.com/imgres?imgur...hUKEwi-idKe5NnuAhVJ8BoKHaqYAqMQMygDegUIARD6AQ

 

[Rroff]

I don't know for sure but if they've designed it fairly close to the application reference then it will have 100uf electrolytics dc blocking on the stereo output - personally rather film caps but that costs more/needs more space.

 

[johhnn]

Thanks! Why only block dc on the stereo output, it is a 7.1 chip labelled as alc887. Shouldn't it be caps to block dc on all 8 channels. Seems pointless to dc block just the stereo channels.

 

[Hotwired]

The engineers know how to do audio, it's super old tech.

But mITX is a bundle of compromises (compared to an ATX board more than twice the size) to get you the essentials in a small motherboard size.

When customers offer enough money this is what happens to create the space for premium audio on mITX:

Plugging in a daughter board.

 

[Rroff]

Thanks! Why only block dc on the stereo output, it is a 7.1 chip labelled as alc887. Shouldn't it be caps to block dc on all 8 channels. Seems pointless to dc block just the stereo channels.

There are but the datasheet only requires lower value capacitors for the additional channels for whatever reason so they are smaller and/or lower quality.

 

[EsaT]

There are but the datasheet only requires lower value capacitors for the additional channels for whatever reason so they are smaller and/or lower quality.

Probably has something to do with that other channels are only there for line signal output.
Meaning 10(+) kohm load and barely any current and power drawn and hence lower capacitance won't be affecting frequency response.
Unlike in case of (front) left/right, which are supposed to be able to power headphones.
Hence needing more capacitance to keep inversely proportional to frequency impedance from rising too high at low frequencies:
http://www.learningaboutelectronics.com/Articles/High-pass-filter-calculator.php

 

[Rroff]

I'm surprised the datasheet only recommends 100uf electrolytics on the headphone out - usually it is recommended to use 220-470uf of that type of capacitor or 0.22-2uf for film caps.

EDIT: Though I guess in theory the expectation is some kind of headphone driver is implemented on the output.

 

[johhnn]

Thanks for the replies, much appreciated.

The reason for the question, i built a htpc and am using the hdmi out from the pc sent to a screen to reproduce the picture.

The pc has analog 7.1 output via 3.5mm jacks which i am running to several power amps to produce the audio.

Picture is okay, sound is not so good.

I just liked the idea of an all in one compact package with the pc doing all the sound functions, volume control, dsp, eq etc, and the picture is output via hdmi. Now it seems i made a mistake.

I want to improve the audio more than anything else. The obvious way as most of my searching has revealed is hdmi out from the pc to a receiver.

Or hdmi out from pc to an av preamp, then to the power amps.

Am leaning more towards the preamp route as there appears to be a general consensus on the net that seperates are better than receivers.

But some spectators feel modern receivers are excellent and good enough for most people.

What do you think. What would you do. If you feel receivers, which one would you go for, and why.

If av preamp, which would you go for.

Many thanks.

 

[johhnn]

As Hotwired mentioned upgrading the mobo is an option or perhaps a discrete card, which of the two would you go for.
Also would the mobo affect the discrete card's performance IE Would the discrete card perform better on a full size mobo or a small form factor.

Thanks