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Building an open embedded audio applicance.

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#1,201
peufeu said:
When you hit stop, the player calls ALSA (linux sound system) to stop the stream, which calls the hardware driver, which is supposed to then set the hardware to output constant zeros and/or set the Mute function and/or power down the DAC (which one applies depend on your hardware)
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Thank you for that information! 🙂

But just to explain my setup.
I use a very simple chain now with BBB, it's: BBB + Master clock reclocked FlipFlops + TDA-DAC-chip.
The Master clock(s) are feed back to the BBB and the switching is working fine between Mieros testfiles (44.1kHz, 16bit and 96kHz, 24bit).
I have now also dared to listen, just have to be playing all the time, and it sounds fine. (The 96kHz, 24bit sound a bit smoother)

(( Per
 
#1,202
miero said:
phi: thanks for report, I'll investigate this.

I've noticed earlier that after stop of playback there is ultra-low frequency pulse which ends with zero eventually.
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Hi Miero,

My output is rock solid at the stopped AC-level, giving a DC-level (Not all true but that depends on the internal design of the DAC-chip)

To me is sounds as if you have an AC-coupled system? An coupling capacitor feeding an high input impedance to an amplifier gives the result you describe.

I realized just after putting my first message here that it would perhaps have been more appropriate to put this in your 'Support for Botic Linux driver' thread (here)?
(Should I move it there instead?)

(( Per
 
#1,203
Hmm, I don't know what miero's driver does, but while more modern DACs could be expected to mute on loss of I2S signal, certainly oldskool TDA dacs don't, and they don't have volume/mute/powerdown feature so perhaps the driver would need to output some blocks of zeros at end of stream to make sure the DAC's internal registers are cleared...
 
#1,205
#1,206
peufeu said:
Hmm, I don't know what miero's driver does, but while more modern DACs could be expected to mute on loss of I2S signal, certainly oldskool TDA dacs don't, and they don't have volume/mute/powerdown feature so perhaps the driver would need to output some blocks of zeros at end of stream to make sure the DAC's internal registers are cleared...
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Just put Squeezelite in the BBB with the Botic driver. Now there is no more problem with DC on the output after pause or stop. Seems Squeezelite is doing something good here.

(( Per
 
#1,210
phi said:
Yes it is fairly straight forward. I should probably have moved this whole discussion to the 'Support for Botic Linux driver' thread that I have references several times already 🙂
There is a good Guide thanks to ChrisMmm (Link). Seach that tread for more information if needed. Good luck !
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Excellent, thanks.
Although the Botic build mdp player is great for a dedicated hifi listening system with a good library of files locally, by using Squeezelite it means that Spotify and bbc iplayer can be used as sources which means I can enjoy it more as an everyday solution too 🙂 Hopefully Miero will find some time to work on his kernel to put his Botic drivers into the excellent SOA software, but in the meantime I'll have a go at adding Squeezelite into the Botic build.
Cheers,
James
 
#1,212
phi said:
Yes it is fairly straight forward. I should probably have moved this whole discussion to the 'Support for Botic Linux driver' thread that I have references several times already 🙂
There is a good Guide thanks to ChrisMmm (Link). Seach that tread for more information if needed. Good luck !
Click to expand...

By the way, I recently tried to get wifi working and failed - needs more investigation. Otherwise fine.

If the miero code can be got working with SoA that would be a great option for Squeezelite users.
 
#1,213
ChrisMmm said:
By the way, I recently tried to get wifi working and failed - needs more investigation. Otherwise fine.

If the miero code can be got working with SoA that would be a great option for Squeezelite users.
Click to expand...
Did you try using the wicd-curses app to configure the wifi?

apt-get install wicd-curses wicd-cli

Then run wicd-curses which gives you a sort of text gui for network setup which I've found pretty handy in the past.
 
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