Raspberry Pi I2S to SPDIF Hat

Just use the iPower to power both devices via the RPi3.

 

Hi Michael,

Thanks for this update.

Is the 502 DAC the only HAT you're going forward with, over the next 3 months?

Is the digital only output HAT still in the works? Or any other HAT's planned to come out over the next 3 months?

Cheers!

 

Currently the plan is to only do the 502 DAC. I have thought about making a different version of the pro, using the same PCM1792 DAC but without the headphone amp. Unfortunately that amp is what is added too much cost, and is probably not of interest to most people.

As for a digital only hat, the digital section of the 502 DAC is about as good as it gets. There is no great benefit of stripping out the DAC.

Cheers,
Michael

 

As far as HAT digital transport goes, what is the difference between 502DAC and 502DACPro?

 

Absolutely agreed - you have my vote for a future Pro version without headphone amp

 

My Christmas treat was a pi and 502dac board ... as well as the time to mess with it.

After only 1 full restart - I have a mostly functional system.





The make up is a pi3 with the 502dac ( not pro ) and a 5inch Elecrow touch screem TFT runniing moOde audio

- I spent the better part of 2 days trying to get the screen and dac to work together - they are supposed to not use the critical pins each of them need but I learned the hard way not to trust data sheets.

I finally clipped off the pins needed by the 502 on the GPIO extention board and the dac fired up without issue. ( well mostly. - I couldn't get the AES to work - using the adapter and standard balanced cable didn't produce anything. The dac was working as the BNC out was good. I made a new cable using some microphone cable and it works just fine )

I have yet to the the touch screen working - tried most every trick in the book but no go. I thought it was the dac interfering but even without the 502 board plugged in - nada. I also need to resize the screen to fit a little better - this is actually not as easy (to me) as it might seem and resulted in me bricking the first attempt at setting this all up.

My plan was to run this with the ability to interact directly via the TFT but primarily run it headless .


thanks Michael , this is a great source for digital playback.

..dB

 

What's the resolution on your display? The next version of moode should automatically scale the output for the standard Pi touchscreen's 800x400 or whatever display.

 

It is 800x480. Looks good actually..dB

 

Just received my 502DAC PRO here in the UK and I have to say the build quality is superb, thanks Michael!

However, I have discovered a noise problem with Moode that I've been investigating all afternoon and hope someone more knowlegeable than myself can shed some light on what is happening...

I'm experiencing low level (digital?) noise using the headphone output of the 502DAC PRO in an "out of the box" configuration with Moode 4.0 Beta 12. This only seems to occur with 16 bit 44KHz FLAC recordings, everything else I have tried ( MP3's, 24 bit 96Khz FLAC, AAC-encoded radio streams) are all completely clean. The system behaves exactly the same whether I select 502DAV PRO or HIfi Berry Digi Pro, makes no difference. The noise can easily be heard in quiet recordings and can be reproduced with everything by playing a 16 bit FLAC and turning the software volume down to 1 or 2. Fortunately, I have found that editing MPD settings and turning on SOX resampling to 24 bit / * KHz seems to fix the problem - the question is, why?

My "out of the box" configuration comprises 502DAC PRO (without volume control board), RPI3, standard Raspberry PSU powering both RPI3 and 502DAC PRO from the Pi power input, Moode 4.0 Beta 12 built with the latest Raspian Stretch lite.

 

Has anyone tried picoreplayer? Which driver I should use? HifiBerry Digi pro?

 

RuneAudio_rpi2_rp3_0.4-beta_20170229_2GB, Pi 2 with touchscreen, 502DAC. What i2S driver should I be using? Nothing seems to wake up the correct MPD output. Here's aplay -l:

**** List of PLAYBACK Hardware Devices ****
card 0: ALSA [bcm2835 ALSA], device 0: bcm2835 ALSA [bcm2835 ALSA]
Subdevices: 8/8
Subdevice #0: subdevice #0
Subdevice #1: subdevice #1
Subdevice #2: subdevice #2
Subdevice #3: subdevice #3
Subdevice #4: subdevice #4
Subdevice #5: subdevice #5
Subdevice #6: subdevice #6
Subdevice #7: subdevice #7
card 0: ALSA [bcm2835 ALSA], device 1: bcm2835 ALSA [bcm2835 IEC958/HDMI]
Subdevices: 1/1
Subdevice #0: subdevice #0

Trying to get digital out via BNC to my Soekris dac1541. Any suggestions? Thanks!

 

If there's no explicit 502DAC driver use the Hifiberry Dac+ one.

 

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Thanks, that works!

 

I've finally completed (mostly) my intended work Pi-based headphone system. Here are the components:

1. Pi 2
2. SmartiPi Touch
3. Pi 2 Design 502 DAC
4. WD Elements USB drive for music
5. GearHead powered USB hub
6. RuneAudio 0.4-beta_20170229, configured for HiFiBerry DAC+ as advised here
7. BNC Nordost BLue Haven cable I had around
   
8. Soekris dac1541 DAC/amp
9. MrSpeakers Æon Closed headphones
10. Impact Audio Custom Infinity balanced cable

My plan is bring the WD Elements drive home from time to time to update with the latest music from my main home server.

I've just ordered a WD USB power kit so that I can power both Pi and WD drive from a single 3A power supply and I can simplify the USB and power wiring. Any suggestions of a nice LPS for this setup would also be welcome.

 

I have the Sbooster BOTW 5/6v version. It is ugly as hell and kinda big but it works really well.
Only downside is that cord after the little black box is a bit short for comfort sometimes. It may dangle depending on your housing for the pi/screen.
https://www.sbooster.com/botw-pp-eco-5v-6v/
It`s the only one I have used so far so maybe you should take that in consideration when I recommend it.
Not a specialist! YMMV

 

I've now repeated this test with Volumio, with exactly the same result. I can't believe that nobody else with 502DAC PRO has seen this yet...

I asked the same question over at the Moode forum, and Tim very quickly came back with this answer:

If you are using MPD Software volume then I've found that 16 bit word length samples result in a very subtle but noticeable noise thats more or less constant in amplitude. If you listen carefully you can hear it at volume 1 or during super quiet passages in the song. [snip]

The fix is either resample using 24 bit * kHz setting or if your DAC supports Hardware volume then select this in MPD settings.

So, I am going to setup 502DAC PRO with resampling to 24 bit * kHz in Moode (or 24 bit Native bit rate in Volumio) as standard, unless Michael or Greg can suggest a better solution?

 

I do think people noticed it before and that`s why a lot of them advice against software volume control.
But I understand that if you only want to use the headphone out of the 502 that is not a satisfying answer.
I think other DAC-hats will give the same result but I can`t say for sure because I always used other outputs to an external amp so I didn`t have to use software volume control. Software volume control removes bits from the audio to make it seem softer in volume. I guess you don`t hear it with 24 bits because you start of with more bits and never reach the point where the noise becomes audible over the music when you remove a couple of bits to lower the volume. I just pulled this out of my ass as a possible reason for the difference between 16 and 24 bits. Please feel free to laugh and correct me if it is a really dumb thing to say.

 

Thanks Humanfly, headphone listening was really why the volume control board for 502DAC PRO was such a brilliant idea, it's just a shame it didn't work out quite the way Michael intended! I still hope to add my own external hardware volume control in the future, software volume is really just for testing. Having said that, the 502DAC PRO sounds amazing straight out of the box and that's before mucking about with separate power supplies and so on.

 

Curious about the meanings of 502DAC LEDs, which are not explicitly explained in the datasheet or in the reference manual. As currently operating, I see the red and the green LEDs on, the yellow one off.