Hi there,
Here are the doings and wrong doings of a group of complete laymen in Vienna trying to built good digital audio players. We have put together a little site https://sites.google.com/a/architekturkonsulat.at/mdxs/home with our findings.
Our main goal is to improve the sound quality by
going thru a bunch of off the shelf DACs + trying to find the best available
built/adding the best power supplies for as many stages in the circuit as accessible (following what we see in Naim Audio equipment since the 70’)
Of the shelf hardware is limited (we like the PCM5122 chip), we trust Volumio (we are just able to put an image on a SD) so all we can do is to create a perfect environment for the given parts. Looking at high end products like Naim Audio one obvious thing they do up the chain is adding designated power. So that’s what we tried and we like the result.
We trust our ears (4 pairs).
It’s a budget question. The SuperTeddyReg costs as much as the DAC. We don’t want to miss it for the DACs analog circuit (best alternative would be the tracking preregulator). For the other regulators single stages are a good start. If you don’t want to get too much into soldering you can get them without the LED reference on ebay. The PSU section and the star ground layout should not be ignored.
Well, we get nervous when looking at a command line.
A good audio player needs multiple talents - a trust in one’s ears to make decisions, hardware and software skills. We partly cover 1 & 2 and want to try to share our findings plainly.
Obviously the quality of the regulator for the DAC’s analog section had the most noticeable effect. We did test regulators for the three digital sections (USB, CPU, DAC) ranging from one cell phone charger to 3 SuperTeddyRegs. Here the difference is more subtil. ± we settled for the 3 cheap single regulators. Any power demand (or fluctuation of such) propagates thru the entire system so we want to separate as much as possible. Looking at a possible reference (Naim NDX) http://www.av.com.pl/avfiles/images/artykuly/strumieniowe/Naim_NDX_srodek.jpg one can see already plenty of designated regulators. This is only a mid range streamer in it’s basic config. - the knob on the upper left perimeter allows you to add 6 external regulators to the circuits.
That might be because of it’s multiple onboard PSUs and that’s what we are talking about. Building a dual DAC system (that’s what you can see in the Naim DAC - again with lots of designated regulators http://www.6moons.com/audioreviews/naim4/2.jpg which we use as our reference) would be great but we totally miss software skills for that.
Thanks for your website, one of us is already interested in recreating such a player. We don’t want to waste the AK4399. What’s about an ODROID C1+ with its i2s MKLC. Maybe one could spare the USB interface then.
That’s an interesting idea. I will investigate the data. It seems to work with their own Hifi Shield.
I won’t have time to try this out until well into next year, so I would be interested to know in case you make progress with this.
The sound of the AK4399 does not only seem to be due to the PSU’s. It’s a very high end chip. I have also tried the dual AK4399 board and it improves on the single board. But the board sees to be faulty and one channel fails regularly. I have also had a lot of problems with the Chinese supplier.
I included Squeeze lite in order to add Tidal, Qobuz and other services support to Pete’s Java mediaplayer because a friend was asking for it. I don’t really use it myself and the integration works but is not really user friendly, so it would need a lot of work both on the server side as well as on the player and the Control side.
I don’t have the programming skills to develop an integration with Volumio2, nor do I have the time available for the moment, sorry about that.
Hello smallangryboy,
do you want to rebuild the copperplate or just make a nice sounding dac in a box?
We did not produce a kit or description so far, but it all starts with bending away (or cutting) all power supplying und ground pins of the 40 pin connector of the pi. (bending away makes a gap of about 1mm which is not a problem, you just have to do the spacing between pi and dac right)
And then at least support the pi +5v, the dac digital +3v3 and the dac analog +5v with a “better power supply” and please leave the switching handy charger power supply away. Don’t forget that the pi and the dac will also need ground, and the leads should meet at one point (star ground).
“Better power supply” is the key to better sound and it starts with a good transformer, rectifier, crc cap array and power regulators using lm317 or even a superteddyreg for the analog side of the dac.
We sometimes leave a lot of stuff away, such as the diodes on the original Texas Instruments proposal for the lm317 or the in or out caps, but we can not guarantee for proper and safe function in different than our setups. We have lots of links to people who have something to say about these things on our site.
All in all these improvements of the pi-dac combo are not really complicated, and if you are really keen to build something we’ll support you.
Have a nice day and sorry for answering late - haven’t been here for a while…
Martin
Hi everyone, an update from our mdXS project: X-7 series mark II - our new reference!
(I’m selling my Naim DAC - it’s still a tiny bit better at very low frequencies but it’s missing something essential - it’s not a source)
So by now we have a volumio/raspberry/iqaudio music player with 5 designated power supplies - e.g. one 3V3 superteddyreg directly to the PCM chip’s AVDD pin 8 analog power (I removed the IQaudIO DAC’s on board LDO). Soon I will add another superteddyreg for the DAC’s digital section (we visited Teddy Pardo in Tel Aviv and were listening to some amazing electronics - his DAC has more that 10 regs!).
Also a standard implementation by now is a CRC configuration (e.g. 2 caps with a 2 ohm @ 3W resistor in between) at the PSU - simple, cheap but effective, it reduces the ripple dramatically before it even gets to the regulators.
Hi troubadour,
I’m going to put together a resource page https://sites.google.com/a/architekturkonsulat.at/mdxs/resources/x-6
for the “naim style shoe box” mdxs over the holidays.
My next one will have the hifiberry DAC+ Pro as well. I will not hesitate to add a separate power regulator to the clocks!!
So far I have some components listed + there is a sketchup 3D model attached. Wiring diagrams will follow…
The pi + the usb need a lot of power - single LM317 will do but a tracking pre-reg ist not much more work.
The DACs digital part (3V3 for chip and clocks) seem to be critical - for us a minimum requ. is a single LM317 + the VBR filter (I will test the dismissed TPS7A4700 for that as well)
We always stick to the TeddyReg for the DACs 5V AVDD (best sound IOO).
PS: Pi 3’s WiFi might have a weak performance inside the metal case. I use a 2 with an edimax USB dongle
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