Raspberry Pi I2S to SPDIF Hat

OK, thanks!

 

My first impression of the Pi I2S hat from Pi2Design.

First of all, I am very grateful that I was chosen as one of the testers... Ok I will skip the formal introduction. As a tester, I owe all of you an answer. My short answer is "buy it". I found the board in my mailbox two hours ago. Simply put, this little board does magic - it sounds unbelievable good.

The only OS I have tried is the piCorePlayer. It works great on the 502DAC HAT. Michael mentioned that the WM8804 transceiver works at slave mode following the PCM5122 DAC chip working at master mode (please correct me). Once I boot the Raspberry Pi 3 B with the picoreplayer 3.02 image, using the picoreplayer web interface, I chose hifiberry DAC+ pro as the audio output device. After a reboot, the 502DAC works like a charm. The on-board clock-indicator LEDs switches when I switch music formats between 44.1k and 96k/192k. My F-1 XMOS usb/spdif convertor (I will call it F-1 DDC thereafter) was connected to a cubietruck (a raspberry pi board alternative running Logitech Media Server 7.9.0 and squeezelite 1.8) via a Straightwire USB-Link cable. I previously modified the RCA co-ax output on F-1 with a BNC connector, it improved the sound a little bit. I also upgraded power supplies on the F-1, the improvement was not subtle.

This is how I compare them: I use a BNC/RCA adapter to connect my F-1 DDC and the RCA input of Gungnir Multibit with a digital co-ax cable. I use a 6ft bluejean 75 ohm BNC cable to connect Michael's 502DAC Pi hat and the BNC input of Gungnir Multibit. In the Logitech Media Server 7.9.0, I set the two converters synchronized so they play the same song simultaneously. I can on-the-fly switch the inputs to compare the two converters. Listened for a while, I will swap the cables to avoid bias - obviously the bluejean BNC cable is better. For this comparison, I use a Anker USB charger (Li-ion battery bank) to power both the Pi 3 board and the 502DAC hat. I will use a external LPS 5V for the 502DAC hat tomorrow. A Dexa Regulator (one of the superreg) for cleaner 5V+ is on the way from partsconnexion.com.

The first impression of sound. I felt that the pi hat need some break-in. The sound was open and very detailed but also a little bright and forward at the beginning. I have to say that the brightness was very subtle. An hour or so later, the 502DAC hat sounded smoother and less "digitized". I felt my F-1 sounded a little bit more "analog". But the 502DAC had better details and the soundstage was fuller and deeper. One thing from 502DAC really stand out was that I felt the positions of the instruments were more 3-D that I felt heights of them in addition to the position and the distance from me. I did not get this feeling from the F-1. For tomorrow, the most important thing I'd like to figure out is whether the 502DAC sounds brighter (little "digital" sound) or simply because it has more details and/or has not burn-in yet.

I am planing to write a detailed report later. I am new here. What would be the better way to post it - should I keep editing my post in this thread or just start a new thread in the "Digital" section? I'd like to report my comparisons between Michael's 502DAC, the F-1 XMOS DDC, and the WaveIO XMOS DDC. It would be interesting because the F-1 XMOS uses CRYSTEK CCHD oscillators (clocks). Both 502DAC and WaveIO use NDK NZ2520SD oscillators. However, the 502DAC is simpler by avoiding the notorious USB.

Thanks for reading.

 

Cool, look what I found in the mail! Just turned it on, trying i2s first It's the D+PRO pin order so hooked straight in.

 

I see you are using the direct I2S pins! Leave it to you to figure that out! Awesome.

Cheers,
Michael

 

Sexy!

 

How does this connect to the Dac? via USB? What's the grey cable?

 

Read back through the thread - I'm pretty sure he's running I2S direct into the Modi board.

edit: got snipped: http://www.superbestaudiofriends.org/index.php?threads/modi-multibit-i2s-input-mod.3492/

 

The silence is deafening...

 

I wonder somebody have tried it with Volumio 2.
Would it work together with 503HTA amp?

 

I used Volumio 2 to test the boards. I simply told Volumio it was a Hifiberry DAC+ Pro.

As for the 503HTA, the final 502DAC can drive the 503HTA analog in from the 502DAC analog out. Although there is a better DAC in the 502DAC (PCM5122 versus PCM5102A), the difference would be hard to tell.

Cheers,
Michael

 

I have no idea if i can get this operational since im pretty computer-pathetic, but ill buy one just to try to get away from usb.
So if you needed one more guranteed purchase to ramp up production, crank up the assembly line!

 

@Michael Kelly Will Volumio 2 work without patching on the 503SPD2 prototype board I have?

 

If you select the Digi+ it will. I think there is a newer Digi+ Pro that does the clock switching, but I am not sure if it uses the same RPi GPIO's as I did.

Cheers,
Michael

 

Production is going forward anyway, but thanks for the vote of confidence!

Cheers,
Michael

 

What makes it better/worse than Hifiberry Digi+ Pro and Kali I2S relocker. They both have clocks for relocking.

 

Good question. Since we use the same clocking scheme, same DAC, it would appear we are the same. But, as we see it these are the benefits:

Simultaneous digital and analog
Headphone out (via TPA6130A2 on the final revision)
Ultra-Low noise and high PSRR LT3042 3V regulator
Dual Ultra-Low jitter NDK oscillators, one for 44.1Khz and 1 for 48Khz based tracks.
Easy to use External Power option
Balanced, isolated digital output supporting AES/EBU
Isolated BNC digital output with support for both Professional Audio AES levels and SPDIF Consumer voltage levels
TOSLINK transmitter for consumer SPDIF
One board for everything!
Cheaper than buying a Digi+ Pro ($45) and a Kali re-clocker ($75)

Downsides:
Bigger board than digi (shield size versus hat size)
More expensive if you did not want analog, or did not want digital, or did not want HP amp.

BTW, I just received our brand new dScope-III. This unit offers not only great analog testing specs (residual THD+N of -108db 5Hz to 96Khz), but also digital. It will allow us to measure the bit error rate on all three digital links, AES/XLR, AES/BNC and TOSLINK. So now we can stop wondering what the effect of various options are, and actually test them. And publish them! Remember, as long as the recovered signal is 100% faithful to the digital data sent, then nothing else matters. All the talk about one digital device sounding better or worse, can only be caused by missing data. Not analog noise on the digital link.

Cheers,
Michael

 

Good sense of humor

 

Hey guys, anyone with a 502DAC prototype getting this loud, high pitched external noise? I can hear it across the room!

Also with headphones you hear all the CPU/processing/networking hash the pi is doing, similar to bad computer usb...

Even the worst scenario pi3/digi+ with cheapie power supply, you need to crank the volume (with headphones and nothing playing) to hear the cpu hash.

Maybe it's a bad component?

Also tried nothing connected, bnc, toslink, i2s, another room, etc. Prob can't do any serious listening tests!


Thanks!!!

May need headphones to hear it thru this, but it is annoying IRL: note: this is an unlisted vid, just convenient to upload there.

 

I just got my 502DAC proto board in a day ago. From my initial testing, I'm not hearing the sound that yours is making. What power supply are you using to feed the 502/pi combo?

Have you tried powering through the pi's input connector? Also, what version of pi do you have (2, 3)?

 

Have Been reading this thread, the small form factor of Rpi sounds like a great solution for transport , looking forward for production version!