16bit I2S driver for TDA1541A

[Supersurfer]

Hi,

Is there a suitable 16bit I2S driver for the TDA1541A dac?
All the drivers I have tried put out 24bit wordlength.

[Tim Curtis]

You should provide more context for example what version of moOde, what hardware being used for audio device, etc.

How are you determining that the output is 24 bit?

[bitlab]

You can use the pcm1794a/dddac1794 driver, it just a generic I2S master driver that supports both 16 and 24bit.

And maybe try to enable sox to force 16bit.

[Supersurfer]

In the attached settings you can see that Moode converts the 16bit data to 24 bit.
Using sox would be not needed if the native file bitrate would be used.

The TDA1541A needs 16bit data.
I use an USBridge signature streamer with fifopi q3 connected to a i2s to simultanous (pcm) data pcb and than to the dac.

[Tim Curtis]

It's prolly MPD's software volume DSP thats padding to 24-bit. IIRC it uses 32-bit float internally. SoX set to 16-bit won't have any effect because IIRC volume DSP happens last in the MPD chain.

What does Audio info list for "Formats" in the Audio device section?

You can set Mixer type to "Fixed (0dB)" in MPD Config and that would take the software volume DSP out of the chain and you should see 16 bit output but it's going to be outputting 100% volume level so you would need a downstream volume control otherwise risk blown speakers or other damage.

You could disconnect your DAC from the Amp/Speakers and test whether the "Fixed (0dB)" setting results in 16-bit output.

[Supersurfer]

Hi Tim,

I checked the fixed volume and it uses the native bitdepth, so in this case 16bit output.
What happens when using software volume at 100% and output in 24bit into a 16bit dac? Will you lose resolution in this way?

Regards,

[Tim Curtis]

I dunno. Some of the old r2r chips accept any bit width and do some sort of conversion internally to the operational bit width.

You could try to find the data sheet for 1541a or 1541 and see what it says.

[bitlab]

@Supersurfer @Tim Curtis tested a solution where the output of MPD is forced to use 16bits.
Will send a PM with custom mpd conf solution when I'm back home.

[Tim Curtis]

Coolness :-)

[Supersurfer]

PM received, thank you! I will check it later this week.