Asynchronous I2S FIFO project, an ultimate weapon to fight the jitter

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#5,023
#5,024
ffeg2008 said:
Previously, DSD Playback in Volumio was only possible via DoP (DSD over PCM) mode, which was encapsulating DSD Audio into PCM samples. You can see DoP as a “compatibility mode” for non direct DSD capable DACs: files would still play, but losing the supposed advantages of DSD. Instead, direct DSD mode allows DSD Playback the way its meant to be played, on compatible DACs.
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I think that text reflects a misunderstanding of what DoP is. DoP is a way to package the DSD data in such a way that it can be sent through a non-DSD-aware path. It is assumed that the end device (DAC) or something on that path understands the DoP packaging and unpacks the DSD data - yielding exactly the same DSD data stream as if it had arrived through a "DSD-aware" or "native" path.
 
#5,025
Julf said:
I think that text reflects a misunderstanding of what DoP is. DoP is a way to package the DSD data in such a way that it can be sent through a non-DSD-aware path. It is assumed that the end device (DAC) or something on that path understands the DoP packaging and unpacks the DSD data - yielding exactly the same DSD data stream as if it had arrived through a "DSD-aware" or "native" path.
Click to expand...


Another words the Volumio developers have absolutely no idea what DoP is ))))
This text, as mentioned above, is from the official Volumio site.
 
#5,027
"DoP is a protocol to transfer native DSD data within the 24bit PCM (I2S) protocol. By using DoP, DSD data can be
sent using existing I2S or S/PDIF connections. DoP is a bit perfect protocol and converts back into native DSD with
no losses. There are NO differences between the original native DSD stream and one re-generated back into DSD
format from a DoP stream."

If I'm not wrong, RPi can only generate direct DSD through a USB streamer. For GPIO, it will be always DSD through DoP. I don't know why there is this limitation.

DoP decoders have already been integrated into FifoPi and the DoP daughter board of IsolatorPi.

DocumentDownload/DopDecoderUsersManual Rev2.0b.pdf at master * iancanada/DocumentDownload * GitHub

DocumentDownload/FifoPiUltimateManualV1.0.pdf at master * iancanada/DocumentDownload * GitHub

Ian
 
#5,029
After reading a lot of the pages in this thread I would like to verify some questions/answers with this community:

1. Am I correct that when I use FifoPi I do not need IsolatorPi as FifoPi itself already provides galvanic isolation?

2. Am I correct that when I use FifoPi I do ONLY need the DOP Decoder IF the receiving DAC does need DSD instead of DOP?

3. If I use a DAC that does not accept an external master clock (A Soekris DAM1941) will the FifoPi solution still work? I'm assuming the reclocking by FifoPi will make things better and leaves less margin for error to the Soekris reclocker..
 
#5,034
Hi Ian and guys, have just bought a pi4 and want to build a self-contained music server that will feed an I2S output via lvds HDMI to a dual AK4495 dac or other dac in a separate enclosure.
Will the fifopi work with the AK4495 dac and do I need an isolator board as I am powering from an Allo Shanti.
Not a newbie but just trying to get my head around a Pi-based system so apologies if this has already been asked and answered.
 
#5,035
@daansan

Sorry for my late replying,

1. Am I correct that when I use FifoPi I do not need IsolatorPi as FifoPi itself already provides galvanic isolation?

Correct. FifoPi has built in isolator, so no need IsolatorPi. But some one said that an IsolatorPi before FifoPi still can eliminate EMI noise more.

2. Am I correct that when I use FifoPi I do ONLY need the DOP Decoder IF the receiving DAC does need DSD instead of DOP?

Correct. But normally I always enable the FifoPi DoP decoding function. Because I'm worry about running DoP decoder inside DAC will increase DAC noise.


3. If I use a DAC that does not accept an external master clock (A Soekris DAM1941) will the FifoPi solution still work? I'm assuming the reclocking by FifoPi will make things better and leaves less margin for error to the Soekris reclocker.

Yes, FifoPi will improve overall signal quality not only mclk. Many community members confirmed that sound quality can be improved by FifoPi even without feeding mclk. But please make sure your XOs for the FifoPi are also good enough.

Please let me know if there is anything else I can help with.

Regards,
Ian
 
#5,037
VuGiaA9 said:
Hi Ian,
I am interested in your FIFOPi board to take the i2s signal to my DAC.
But i don't know if FifoPi could work with my DAC. I own Muse 296 dac (master clock mode with i2s input)
Muse Eight DVD/CD transport & 296 D/A processor

Help me, please.

Thank you.
Click to expand...

Hi VuGiaA9,

I'm not sure if your Muse 296 DCA can take LVTTL level I2S from my FifoPi through u.fl cables. But I'm sure it will work with my TransprotPi which I'm working on right now.

I'll post something about TransportPi very soon.

Regards,
Ian
 
#5,039
I mount newclassd NS osc, with 11.2896 quartz for 44 sampler Some time when i change songs eith different format to dsd/pcm/mqa all in 44khz sampler, the sistem loose the dac, on display i see no signal..............
The rpi still work but no sound out. I need reboot all the sistem. The sistem work for 1 our 2 our with no problem and sometime the problem arrive, all voltage is ok
 
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