A NOS 192/24 DAC with the PCM1794 (and WaveIO USB input)

[stijn001]

.....What would be super cool is to combine the sample rate & frequency data from the WaveIO PLUS the playback state information outputted directly by the transport, all on one 20x4 LCD. .....

That would indeed be "super cool", can't wait for you to tell us how. ;-)

 

[beardman]

Hello
I tried to wire the Doede dac to volume..and on to amp ,,without caps or anything
plays fine but,,a lot of clicking when i use my dantimax relay volume ,,it must be the dc from the dac
i have caps in my input on amp
i use balanced wiring from dac to volume to my Groundsound digital filter

if i use caps after the dac,,shall i use caps to both positive and negative output ??

best Bjarne

 

[rovinggecko]

Any suggestions on how to add volume control, befitting the dddac quality?

 

[biarritz]

As a happy DDDAC1543 MK2 24full kit user, with JRiver Media Player (WASAPI) and a Squeezebox Duet connected via I2S, I have been looking at upgrading to 24/196.

I'm using a Synology NAS with Logitech Media Player and now have replaced the Duet with a Rapsberry PI and Hifiberry DAC running PiCorePlayer. My plan was to give both my kids a rpi with hifiberry dac, but I was very surprised with the audio quality of this simple solution.

Last week I obtained the Hifiberry DIGI and connected it to my DDDAC through SPDIF. my plan is to purchase or better, build a new DAC using the Hifiberry DIGI as input. USB is for me not the way to go because I want to move my PC away from my audio system.

As I'm very please with the previous DAC form Doede and my first choice would be the new DDDAC 1794 kit. I almost did the purchase, but before checking out I read most of this discussion thread. That is were I stopped the purchase.

1. I wanted to buy the new mainboard with SPDIF, but was surprised when I read that it only supports till 20 bit.
   
2. I also noticed that most of you that are using the rpi connect it directly by I2S through the header p5.
   
3. The specs of Hifiberry DIGI states that it is using a High-bandwidth output transformer that provides full galvanic isolation of the electrical output.It is the pulse T6074NL

So my question wanting to get the best of two worlds (Rpi - I2S -DDDAC 1794 or Rpi - Hifiberry DIGI - SPDIF - DDDAC 1794) what is the best way to go from here?

I understand some of you are still experimenting yourself, but some kind of isolation between the rpi and dddac when using I2S is probably needed.

Can I get to 24 bit using the old SPDIF board from the DDDAC 1543?

 

[Supersurfer]

@biarritz,

I2s, even without galvanic separation, is better than spdif.

Spdif is much more prone to jitter than i2s because of the combined data stream. Even galvanic separation will introduce jitter, so it is more a choice of accepting some ground pollution or accepting the added jitter; just try both and stick with the best in your system.

The transformer on a hifiberry is probably a pulse transformer for spdif format, so you cannot get the i2s from this.

Regards,

 

[stijn001]

....
if i use caps after the dac,,shall i use caps to both positive and negative output ??...

Hi Bjarne, the cap is only needed on the postive to get rid of (more) Vdc, if there is any, if that's what you are after..

 

[biarritz]

@Supersurfer
Thanks for your explanation. I will try to connect the rpi over I2S with the old DDDAC first and hear the difference.

 

[stijn001]

Biarritz, there are a few other embedded options in the making, one being based around the Beagleboard black + a Cape by twisted pear, which are promising to even better the RPi/I2S option. Spdif is mostly disgarded with regards to further development due to bitrate limitations. Still very good en usefull in it's own right off course.

 

[dwjames]

Stijn, I was looking back over the thread and noticed how cool the rj45 and USB connectors you used on your case are do you have a part name/reference for those please?


Also, has anybody got this DAC running via a Raspberry Pi using I2S out and managed to get Squeezelite working? I've tried using the /etc/modules configuration as recommended to get Volumio working, but I suspect I also have to define the device name in the Squeezelite configuration file too...

 

[beardman]

Hej stijn001
why shall i not use a cap in the negative line ??..i use the balanced wiring ,where i use positive and negative and common...direct to my balanced volume

The sound
the best sound is without caps or trafo or preamp
Also good is without caps or trafo to my Aleph 1.7 pre,,(caps in input of Aleph )

what is the best way to lower the dc from dac ?...use a trimmer on the I-V resitor to make the dc lower ,,or what ?

best Bjarne

 

[dddac]

Hej stijn001
why shall i not use a cap in the negative line ??..i use the balanced wiring ,where i use positive and negative and common...direct to my balanced volume

The sound
the best sound is without caps or trafo or preamp
Also good is without caps or trafo to my Aleph 1.7 pre,,(caps in input of Aleph )

what is the best way to lower the dc from dac ?...use a trimmer on the I-V resitor to make the dc lower ,,or what ?

best Bjarne

See which has the higher DC voltage against Common, pos or neg…
Than put a 10 k multiturn trimmer parallel to Rload and now you trim (let it warm up 15 minutes) to as close to 0mV as possible

 

[beardman]

Shall i measure without the volume on---take the cable out----i get a higher dc with the volume cable in--
come close to zero mv ,,without the volume cable...but higher with cable on
best Bjarne

 

[dddac]

strange, that should not happen, unless there is a GND Loop / connection somewhere.
do you connect the volume between pos and neg, no wires going to common? this is how it should be

 

[beardman]

oh i see...i have wire it with common pos and neg...
i will try to remove this now

 

[biarritz]

@dwjames,
If you use PiCorePlayer (https://sites.google.com/site/picoreplayer/home) you get an image with Squeezelite embedded. It has a simple user interface where you can select a soundcard. I currently cannot test it, but you should use 'I2S Audio DAC (Hifiberry I2S DAC)' to activate the I2S output on the Pi.

 

[beardman]

Thanks Doede
this was just the right thinks to do....and,,only very small clicking from volume**

 

[dddac]

nice I could "solve" it

 

[dwjames]

@dwjames,
If you use PiCorePlayer (https://sites.google.com/site/picoreplayer/home) you get an image with Squeezelite embedded. It has a simple user interface where you can select a soundcard. I currently cannot test it, but you should use 'I2S Audio DAC (Hifiberry I2S DAC)' to activate the I2S output on the Pi.

Brilliant, thanks
I'll give that a go

 

[dwjames]

@dwjames,
If you use PiCorePlayer (https://sites.google.com/site/picoreplayer/home) you get an image with Squeezelite embedded. It has a simple user interface where you can select a soundcard. I currently cannot test it, but you should use 'I2S Audio DAC (Hifiberry I2S DAC)' to activate the I2S output on the Pi.

Brilliant
so this works straight out the box, no editing files or messing around with anything. I needed to use the previous version of PiCorePlayer 1.15.b as it seems 1.15.c has an issue with loading the I2S driver and hangs, but 1.15b works great. Highly recommended

Just to recap, I have replaced my WaveIO and Wandboard running CSOS with a Raspberry Pi with a P5 header soldered on running PiCorePlayer (a squeezebox player emulator)
It seems PiCorePlayer is even better than I had hoped as it supports upsampling with the SOX library like CSOS does (recommended settings for the 1794 are vM::2) but also PiCorePlayer is a tiny image (about 50mb) and runs totally from RAM once it's loaded, so there's no issue with having to properly shutdown for fear of corrupting the file system and having to reload the software

The sound with direct I2S from the Pi is definitely at least as good as the Wandboard + WaveIO board, possibly a little better... I don't know yet, I need to spend some more listening time.

I need to shorten the wires and I also have an isolator to try, maybe next week.

I was using the 2 x 1A super low noise power supply before for Wandboard and WaveIO, so now I have 1 supply free. they're switchable with a jumper between 5 and 3.3v, so I might try feeding to the 3.3v regulator on the mainboard

and just for the sake of completeness, here's the very helpful I2S wiring diagram Palmito posted

and again, but via an isolator

Very happy with that!

 

[stijn001]

Stijn, I was looking back over the thread and noticed how cool the rj45 and USB connectors you used on your case are do you have a part name/reference for those please?...

They are by Neutrik, NE8FDP&NAUSB-W The USB one is reversable incase you'd wonder (like I did).