Raspberry Pi I2S to SPDIF Hat

@Wfojas what cd player is that? You got me curious...
Also I'm interested in the mutec effect, as a usb converter VS pi2\digi+ and as a reclocker with the pi\digi+ VS the cd player.

 

LOL, its a Audio Research Reference CD8, which has a tubed output stage. The Asus notebook to a Berkeley Audio USB to the Gungnir Multibit is also good, beating the Rpi via usb -> ifi iDSD and the Digi+ SPDIF direct to the Gungnir Multibit.

I hope the Asus/Mutec comes close even with the Asus/Berkeley, though. At least that's a more reasonable assumption and value proposition.

I haven't given up on a simple renderer, yet. It could be @Michael Kelly 's 503SPD1/2 in a case with an uber power supply for the RPi and SPD boards in an electrically quiet box, or a Micro Rendu. All this stupid fiddling is just to whatever makes me want to listen to more music, which is the goal. Everything else is just a way to get to that, lol.

 

Do you have the equipment to measure/see this? How do you know your layout and the external clocks will out perform this? 50ps is actually damn good... Still... there's more to it than jitter-- sure potentially it may sound better, but is less jitter the cause?

We might have the opportunity to be pretty precise here. Instead of waving our hands around "it's got less jitter" when it may be coming from something else.

 

I've been listening more to the 503 and I must say I continue to be impressed with how engaging this product is acting as renderer in my system. To my ears, this board helps to make the music more engaging to me, especially with vocals where I am hearing details I have not heard before. @Michael Kelly , there must some "secret sauce" in this board other than simply clean 3.3V right???

 

I have a LM338 based LPS feeding DC into two Reflektor-D LPS's ready to supply the cleanest power possible (separate 5V supplies) to a Pi3 + SPD2. I'll be using the SPD2 with these supplies sending AES to the Schiit Yggdrasil, and comparing to the Yggdrasil USB3 being fed by an Uptone Regen, which will also be powered off a Reflector-D LPS. Should be an intense shootout

 

Well, that is a BIG difference though. Plus we use a 4-layer board with ground and 3.3V plane to get the best power distribution. And we isolate the Pi ground from the analog ground with a ferrite bead to further reduce noise coupling. Digi uses 2-layer which is done for cost, not for sound quality.

Michael

 

Well, if you put it that way! LOL! In all seriousness, this just sounds so good! At least to me, this a great sounding HAT not just in comparison to the Digi+ but also compared to my fully tweaked PC. Great work!

 

Interesting that you will be comparing the SPD to the Regen. How are you going to tell if the differences you hear are not caused by Yggdrasil AES or USB input? I have read that the Yggdrasil AES input is better than its USB3. Have you thought about putting the SPD after the Regen then sending AES to Yggdrasil?

 

@Michael Kelly question regarding the multiple clocks in the SPD. Are you envisioning the user has to go into some web interface and manually select which clock freq to use? Or will this be command line process via SSH? Or will the SPD be able to detect the input sampling rate of the music and auto select the right clock frequency? Not sure if you thought that far ahead considering the SPD isnt even made yet!

 

After reading tboooe impressions, this picture is perfect example what i think about this project:

 

There will be a small amount of code that detects the incoming sample rate and selects the right clock. This is very similar to how the DAC Pro from Hifiberry works. From the user point of view this is all invisible, but it will mean we have to supply you a modified version of the software you're running. At first that will be Volumio and RUNE audio. We can do others on request and for the more adventurous of you, you can do it yourself with a patch we will supply. Eventually it will get rolled into the various software platforms when they update from the Linux code base where our stuff will be.

Cheers,
Michael

 

More like:

 

so I set up my rpi3 today.. with rune audio then volumio 2 rc1. used stock canakit smps wall wart and schiit wyrd with geek out 450 and hd800 headphones. the usb had a weird intermittent noise issue.. actually worse than pc. not sure if it's related to the smps wall wart or just poor usb in the rpi3. the wyrd didn't help. I'm gonna shelve it until I can try the HAT from this thread.. hopefully that's better

 

I've thought about that first point, and hope to borrow another AES source (e.g. Bryston BDP-1) at some point in the near future to compare against the SPD2. I've also read that the AES is better than USB feeding Yggdrasil, which is why I'm really looking so forward to the comparison =D

Yup, I've thought about putting the SPD after the Regen. In fact, I was thinking of doing all of the following exhaustive comparisons:

-Strait USB from tweaked laptop (laptop run off SMPS power brick) -> USB3 Yggdrasil
-Strait USB from tweaked laptop (laptop run off a LPS) -> USB3 Yggdrasil
-Regen (SMPS power) -> USB3 Yggdrasil
-Regen (Reflektor-D LPS) -> USB3 Yggdrasil
-Schiit Wyrd -> USB3 Yggdrasil
-rpi3 (from SMPS) -> 5V jumper connected -> SPD2 AES or BNC to Yggdrasil
-rpi3 (Reflektor-D LPS) -> 5V jumper connected -> SPD2 AES or BNC to Yggdrasil
-rpi3 (Reflektor-D LPS into Regen into rpi3) -> 5V jumper connected -> SPD2 AES or BNC to Yggdrasil
-rpi3 (Reflektor-D LPS) -> 5V jumper disconnected -> SPD2 (seperate Reflektor-D LPS) -> AES or BNC to Yggdrasil
-rpi3 (Reflektor-D LPS into Regen into rpi3) -> 5V jumper disconnected -> SPD2 (seperate Reflektor-D LPS) -> AES or BNC to Yggdrasil

 

We should make a rule that no one using the pi with wall wart smps should be allowed to comment here

When I tried my wallwart smps I thought my system had a broken because of the noise. @uncola though pi USB is far from ideal don't wait for the hat, try an LPS. .. even a cheap one with lm 317 or similar will do the trick.

 

how about a battery supply? any suggestions on a known good one? or LPS I'm open but can't be too expensive heh
edit: the regulators on the HAT should take care of this(noise) though right? I was planning on doing coax or aes to my soekris prebuilt dac(arrives in late june)

 

I think a battery supply is probably the most reasonable solution for a lot of us, especially since the Pi is so compact to begin with.

 

I hear no noise from my Pi3 running USB into Hegel DAC with smps.How is the Pi3 connected to your LAN? Since Pi shares bus between LAN and USB, that might be cause of noise.

 

Did I put you on the test dummy list? If not, I will! In fact, to all those wanting to participate in the testing of the SPD1 or SPD2, please send me an email with your contact info and shipping address. We will send out at least 5, but may be able to squeeze another few in return for a detailed report. BTW, we will want to disclose some of your comments and opinions as part of our marketing, but it would only be with your consent. Even if you publish it here in the forum, We would not publish without consent.

Cheers,
Michael
[email protected]

 

Also please provide me your username from the forum so I can figure out who is who!

Cheers,
Michael