There certainly are more moving parts in Chain 1.
HDMI audio is slave to video which means that even if you play pure audio, black video is generated to go with it. This causes lots of stuff to light up in the equipment and in the AVRs I measured, substantially degrade performance.
As watchnerd mentioned, all DACs are the same ESS 9023.Thank you for your reply but I do not completely understand what the hardware underlies each graph in this image:
[pretty, colorful pic removed]
RPi I2S + ES9023 DAC
BBB I2S + ESS9023
USB-I2S-2+ ESS9023
USB-I2S-1+ESS9023
and what is the difference between USB-I2S-2+ ESS9023 and USB-I2S-1+ESS9023?
As watchnerd mentioned, all DACs are the same ESS 9023.
RPi I2S + ES9023 : Raspberry Pi native I2S interface with a 44.1kHz data rate
BBB I2S + ES9023 : Beagle Bone Black native I2S interface with 48kHz data rate.
USB-I2S-2 + ES9023 : “Mystery” USB to I2S interface number 2
USB-I2S-1 + ES9023 : “Mystery” USB to I2S interface number 1
CD Player : “Mystery” “inexpensive” commercial CD player (unknown DAC)
Brian from Dangerous Prototypes created the plots and for some reason doesn’t mention the details on the “mystery” items.
I2S on the RPi is created using a 19.2MHz crystal oscillator, which cannot create the bit clock for 44.1kHz using an integer number of clock cycles, so jitter is intentionally created by the Broadcom chip by varying the divisor to create the bit clock. This problem does not occur with a 48kHz sample rate.
If you ignore analog noise infiltrating the analog sections of your system (by choosing components, e.g. DACs, etc., that avoid it), but you do worry about jitter (some people don’t so much), then there are 3 options for using a RPi: use 48kHz sample rates (or multiples thereof), or use a different clock (asynchronous USB, or I2S with reclocking, as watchnerd suggests). Don’t use the analog output of the RPi.
@SoundAndMotion
Thank you. In regards to option #2
"or use a different clock (asynchronous USB, or I2S with reclocking, as watchnerd suggests)."
Would this be an example:
RPi -> usb-> Singxer XU-1 -> i2S ->DAC
but isn't the digi+pro 'limited' to 96khz output? and pcm only?I haven't seen any measurements for the XU-1, so I don't know how effective it is at lowering jitter.
But unless you need the multiple outputs, the $399 XU-1 is a lot more costly than the Digi+ Pro.
sorry i should have checked. I thought something was missing from a 'full featured' DAc. It's DSD that it does not do. but i2s does. i have a very limited dsd collection from when i was trying to hear a difference (did not)
Edit: It looks like you can also solder on a dedicated I2S connector.
https://support.hifiberry.com/hc/en...2S-transport-using-DIGI-as-I2S-bus-controller
it shows how the DAC+ pro is used to control i2s.
Finally there's talk of removing resistors somewhere (last post) but I dont know which ones they refer to.