I got the 502 the week that they introduced the Eitr (I think) so I might have gone Eitr a couple of days later.
But I was growing increasingly weary of USB and all the fixes it seemed to need. So I started looking for options.
I wanted to keep my pi because I really like Volumio and I am a cheap person so I dont want to pay 500 euros for a lifetime subscription
(but thats just me, Roon looks sweet enough)
The only three ways I found were the Hifiberry DAC+Pro, The Allo Digione and the Pi2Design. The DAC+Pro needed soldering and for me that is a great way to void warranties so that was a no-go.
The Digi-one and the 502DAC both have BNC and coax out which is what I was looking for. The 502 added the AES option and also has the dac part which might come in handy if I sent Gungnir in for an upgrade.
Also the way the boards isolate the signal from the electrical part is somewhat different. The DigiOne uses digital isolation and the 502 does it by hardware. In theory I preferred the latter.
I read a couple comparissons and they seemed to agree that the 502 was more `organic` sounding and the Digione more analytical but they were no real in-depth reviews. Again this to me was in favour of the 502.
The price also seemed better with the 502 but this turned out to be wrong because after tax and shipping I paid like 20 or 30 euros more for it than the Digione would have cost me.
Over on the other side there is a person that owns both the 502 and the Eitr, so maybe look him up
I can`t help you there. Actually the same goes for the Digione. I am planning on trying the Digione when the price drops.
Their Kali board now only costs halve of what I paid so I`m counting on that. It measures really well but there is some discussion on where in the path you should measure
So I gues I`ll have to hear it.
I already owned the S-booster BOTW so I still use it. The creator of the 502 states that it is overkill but I think it still adds some ease to my sound. This may be entirely up to placebo-overspending-effect.
But I also had buzzing and hissing from the previous cheap raspberry wallwarts. This is also gone now. BTW the digione takes power from the raspberry. The 502 has it`s own powerinlet you can use so it will feed the raspberry via the GPIO pins.
In previous setups feeding the power through the GPIO-pins really made a difference in SQ because you bypass the raspberries own shotty usb power inlet and power handling.So my guess was that this would also be the case here. I also have my files on a different system so I use the network connection and that too seems to benefit from a stable powersupply. All-in-all I think if you really want to squeze the last drop of SQ from the pi you need a decent powersupply. The IFIpower might do just fine but I decided to go all the way because I like to change things up and some boards really benefit from LPS where others only do marginally so. I think the 502 does marginally so.
So yeah...that is a huge post. Basically I am saying I don`t miss USB at all.
I might eat my words once I hear USBgen5 but my gungnir has the first gen-usb and the difference between usb and BNC was huge.
So that is the only thing I know for sure. The rest is all very subjective and hearsay.