VoCore 2 sound output - best way?

Spool
 
Posts: 6
Joined: Sun Oct 23, 2016 8:35 am

VoCore 2 sound output - best way?

Mon Aug 03, 2020 6:48 am

Hey. It's been a while since I last played with VoCore.

Yay, so I was cleaning my workshop and I found my unused VoCores. Some years ago I apparently ordered 5x VoCore and 5x VoCore 2, now I have 10 of them laying around. I thought I'd put them to use somehow and I was thinking of using a Vocore2 for a small media player running MPD. I was wondering what's the best way to hook up VoCore 2 to output sound. I've noticed there is I²S available on the board where I could hookup a DAC. But I've read some threads here that many people have been having problems with audio noise. Have these problems been fixed? Should I just use an USB sound card instead sine the board also has USB pins?

Thanks in advance.

Also, Vonger, please:
This site is *still* running on plain HTTP! This allows 3-rd parties to read traffic and potentially siphon sensitive information like login passwords. It's 2020 so there's no excuse for still running a webserver on an insecure protocol. Please add support for HTTPS as soon as possible. I'm getting an error trying to connect to https://forum.vocore.io/

Vonger
 
Posts: 821
Joined: Sun Oct 19, 2014 6:00 am

Re: VoCore 2 sound output - best way?

Wed Aug 05, 2020 2:09 am

Here are some note to reduce the noise:

1. separated the power supply of wifi and sound
2. move sound chip away from the on board antenna
3. if 2 is not possible, remove that on board antenna use U.FL antenna instead.
4. bigger caps

about https, you are right, i will handle it soon.

Spool
 
Posts: 6
Joined: Sun Oct 23, 2016 8:35 am

Re: VoCore 2 sound output - best way?

Mon Aug 10, 2020 7:55 am

Dear Vonger,

Thank you for the answers, but I am confused by some of your suggestions. Could you please explain it in a bit more detail? I just want to make sure that I understand you correctly.

1. separated the power supply of wifi and sound
Okay, so judging by the way you wrote this, am I correct to assume that the WiFi is the main culprit for the audio noise? In that case, if I don't use the wifi (use ethernet instead), will there still be noise? You also mentioned separated power supply for wifi and "sound", but the wifi is on board and if there is any "sound" also on board, it can't be separated easily. Did you mean separate power supplies for VoCore2 and external I²S DAC that I am supposed to implement myself?

2. move sound chip away from the on board antenna
Okay, so again by mentioning the "sound chip" did you refer to the I²S DAC or something else? Also, you never mentioned anything about using a USB sound card, so I assume using I²S is better than USB?

3. if 2 is not possible, remove that on board antenna use U.FL antenna instead.
Can I use the u.fl connector with an external antenna without physically removing the on-board ceramic antenna i.e. disable it in firmware somehow?

4. bigger caps
I take it you mean bigger decoupling capacitors for the power supply?


Thanks in advance!

Vonger
 
Posts: 821
Joined: Sun Oct 19, 2014 6:00 am

Re: VoCore 2 sound output - best way?

Mon Aug 10, 2020 9:04 am

1. If you do not use wifi, there will be no noise at all. :)
2. Sound chip is the ES8388 on bottom, using I2S.
3. No, it need to physics remove.
4. Yes, for power supply, but effect is little.

Spool
 
Posts: 6
Joined: Sun Oct 23, 2016 8:35 am

Re: VoCore 2 sound output - best way?

Mon Aug 10, 2020 5:27 pm

Vonger: Some of your replies are rather cryptic.

Vonger wrote:2. Sound chip is the ES8388 on bottom, using I2S.

I've taken a look at the schematics and I've learned a few things. First of all, the sound chip is apparently ES8388, but according to schemaitics it's WM8988 so it took me a while to find. Second, this sound chip "on bottom" that you're referring to does not mean the bottom side of VoCore2, but rather the dock itself, if you're using one. The VoCore 2 board does not have any sound chips, only the I²S output that can be interfaced with a DAC. So this answers my previous question whether the sound chip refers to an I²S DAC that I'm supposed to implement myself and the answer is yes, since I don't use the dock.

Gerarda!

Vonger
 
Posts: 821
Joined: Sun Oct 19, 2014 6:00 am

Re: VoCore 2 sound output - best way?

Tue Aug 11, 2020 3:33 am

haha, sorry about that, these are too familiar for me. :)

If you want to try I2S, this example might help.
http://vonger.cn/?p=14302

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