John Tucker of Exemplar Audio did the work. He was taken aback by how great of a media server the RPi5 is (running LibreELEC), even when compared to $$$$ audiophile media servers. After some discussion, he decided he wanted to give away how he did it. The linear power supply made a big difference. We're not sure why, but suspect it's not necessarily because the RPi5 itself benefits significantly from using a linear PSU instead of a SMPS, but rather by not having a SMPS in the same circuit as the rest of the audiophile gear, which is quite sensitive to the noise a SMPS creates.
Total parts cost is relatively minor, especially when compared to what others charge for "audiophile" power supplies or what an "audiophile" media server costs. (eg: https://houseofstereo.com/collections/w ... al-edition )
The transformer and the enclosure are the most expensive components. Getting the PCB printed is another expense. The rest of the parts are on Digikey and all pretty cheap.
I've attached an ExpressSCH file, an ExpressPCB file, a bmp of the schematic, and a parts list
a few notes:
The express PCB file has space to add an additional two schottky diodes in case you have a power transformer that doesn't have a center tap and need a bridge rectifier. Just ignore those if you're using the 1182Q9 in the parts list. If you provide your own power transformer it needs to output 9v and be capable of at least 6A. The 1182Q9 is very over spec, but something that's closer to the correct spec isn't much cheaper (or in stock).
We used a 6016H split body enclosure with plain end plates from context engineering ($45 for natural aluminum $76 for black) https://contextengineering.com/split_bo ... sures.html
A heavier enclosure wouldn't hurt, if you're willing to pay for it.
Also, soldering a 18awg wire to a USB-C connector is a bit beyond my pay grade, so I simply bought a $12 RPi5 PSU off amazon, cut the cord off of it, and soldered it to the PCB
Since the PSU can not negotiate with the RPi5 that it's capable of providing 5A, add PSU_MAX_CURRENT=5000 to the eeprom bootloader config.
One last thing worth mentioning is that we're using a USB DAC that has an Amanero USB-I2S board which is typically powered by the 5v rail of the USB out. We opted to cut that trace on the Amanero and have it powered by it's own regulated 5v. (credit: https://www.diyaudio.com/community/thre ... st-7262607 ) This definitely made a difference.
Just for fun, we also made a USB cable that doesn't have the 5v wire at all.