So... This is my first real post on this forum and I have a question for all you tech savvy people.
If using WM8804 chip for SPDIF for input, could I be using ProtoDAC TDA1387x8 for output?
The reason for this conversion is that I would like to stream the sound from my computer by SPDIF to the ProtoDAC. But the "normal" ProtoDAC does not accept audio in because of the TDA1387x8 (TDA1541A) chip. I really like the simplicity of the ProtoDAC with minimal components and clean sound an would like to not use USB devices for the audio transport. The cleanest way I can think of transport would be directly to the ProtoDAC board. That way there would only be one board or accessory on the Raspberry.
I have made a schematic of how I think it could work but I really need help to figure this out and perhaps find even a better solution. I have only used other schematics to make my own edit so there should be errors in it and even some things that might not work.
So please help me make this one-stop-hat work 🙂
If using WM8804 chip for SPDIF for input, could I be using ProtoDAC TDA1387x8 for output?
The reason for this conversion is that I would like to stream the sound from my computer by SPDIF to the ProtoDAC. But the "normal" ProtoDAC does not accept audio in because of the TDA1387x8 (TDA1541A) chip. I really like the simplicity of the ProtoDAC with minimal components and clean sound an would like to not use USB devices for the audio transport. The cleanest way I can think of transport would be directly to the ProtoDAC board. That way there would only be one board or accessory on the Raspberry.
I have made a schematic of how I think it could work but I really need help to figure this out and perhaps find even a better solution. I have only used other schematics to make my own edit so there should be errors in it and even some things that might not work.
So please help me make this one-stop-hat work 🙂
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If you want just an SPDIF input, why do you need the RPi? Just get an SPDIF to I2S converter board from Ali and connect BCK, LRCK and DATA to the ProtoDAC GPIO 12, 35, 40, respectively. I have used this, and it works very well. To be completely correct, there should be a method of inverting polarity.
If you want USB, there are USB to I2S boards like this https://www.aliexpress.us/item/2251832687799079.html Polarity could be inverted digitally here.
Do you want to be able to switch from USB input back to streamer functionality with the RPi? If this is the case, one method I have recently read about is to use the RPi in USB gadget mode (no personal experience). Some RPi's are able to operate in gadget mode such as the Zero, Zero 2W, 3A+ and 4B(?). In gadget mode the RPi could accept input from the USB port and output I2S to the GPIO. Jitter will likely be higher, because the RPi clock is used.
In your schematic, R4 and R5 should be no greater than 430R to prevent clipping with a Vdd of 5V. Even 430R may clip with some high output modules.
If you want USB, there are USB to I2S boards like this https://www.aliexpress.us/item/2251832687799079.html Polarity could be inverted digitally here.
Do you want to be able to switch from USB input back to streamer functionality with the RPi? If this is the case, one method I have recently read about is to use the RPi in USB gadget mode (no personal experience). Some RPi's are able to operate in gadget mode such as the Zero, Zero 2W, 3A+ and 4B(?). In gadget mode the RPi could accept input from the USB port and output I2S to the GPIO. Jitter will likely be higher, because the RPi clock is used.
In your schematic, R4 and R5 should be no greater than 430R to prevent clipping with a Vdd of 5V. Even 430R may clip with some high output modules.
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I am planing to build a streamer/hifi deck with display, volume knob with all the inputs and outputs in a single box. I can say that I havent thought of seperating the DAC from the PI before. The build would have a screen displaying source and output signal with info from CamillaDSP and if using MPD show album cover or Spotify info with the information about source and output.
It shouldn't be to hard to include a switch to go from streamer mode to direct throughput. That might even be easier to build then trying to combine everything on a single board too 🙂. I will have to rethink my build.
I really thank you for your input here!
It shouldn't be to hard to include a switch to go from streamer mode to direct throughput. That might even be easier to build then trying to combine everything on a single board too 🙂. I will have to rethink my build.
I really thank you for your input here!
There are better USB to I2S boards such as the I2SoverUSB . Isolation is important with USB. Or you can get inexpensive USB isolators to use with the Ali USB to I2S boards.