But in the south of Sweden you should have acceptable summers, I think? I’m located in the centre of Europe (Austria)
You are right my friend. It was a joke. Summertime in Sweden IS fantastic.
Now some questions concerning the BERRYNOS 1543 converter in order to achieve maximum sound quality:
As I read out of the schematic are CON 1 and CON 2 the regular power supply connectors that demand AC- Power. So I only need to connect a power transformer with 2 secondary sections of 7.5 to 9V, right?
Yes that is right The DAC part requires only a transformer attached to it.
CON 3 is the 5V supply for raspberry pi, which powers raspi up through P5 connection-block? So I don’t need to plug a 5V PSU in the mini- USB connector of the pi?
That is right too. Please observe that you have to apply 5V DC.
3) Are the power supplies of BerryNOS DAC and raspberry pi completely separated in this configuration?
It is NOT galvanic separated ground plains between RPi and DAC.
But we have spent a lot of effort to minimize the interference between them.
- Is it possible to connect for example high quality self-made symmetrical power unit (+/- 7.2V DC) to CON 4 and would I have to remove components in this case? Do you see any benefit for sound quality with this method and the possibility of tweaking here or is the on board power management through CON1 and 2 perfect for the DAC?
That vas the intention with CON_4. To give the diyer the possibility to apply own symmetrical power supplies of their choice.
BUT. If you look little closer to the on board regulators you will find an own developed “hybrid” circuit that combines a good quality serial regulator 317/337 with a discrete shunt regulator (low linear impedance from DC to very high frequency) attached to the adjustment pin of the serial regulator.
Of course there is tons of different PSUs out there but I have hard to believe that many of them can beat this one.
- When I order the DAC with additional spdif input, is then a similar RCA connector mounted on the board and is it possible to play (maybe switchable) the DAC with a CD- Player and the Pi connected?
There is no RCA onboard connector when you order that option. The RCA connector has to be attached to the board with a cable.
The I2S output from the spdif chip and the RPi spdif output is connected together .
So it is intended to be used one at the time.
Theoretically you can play from the spdif input with the RPi attached to the board IF the RPi is powerless but I would not recommend it for performance reasons.
- What is the maximum current drawn by the DAC?
- I2S- Configuration: Are there jumpers included for easy made comparison of the two versions? If not, which one would you prefer on sound aspects?
Yes you can play a track move the jumper’s play same track and compare.
Ok let me think how to explain that with sampling frequency in a way that ordinary people understands what I am talking about.
Easiest way should be to post some oscilloscope pictures but I don’t have some right now.
So let’s say that when you are playing 44.1KHz you don’t have enough with bandwidth to reproduce frequencies up to 20KHz and you can see (and hear) the effects already after 10kHz but you have minimal digital processing instead.
And it is the other way around when you up-sample to a higher frequency.
Which sounds best? There is as many opinions as people about that.
- I’ve no symmetrical connections on my tube amp. Is the sound degradation with RCA plugs connected clear to verify or rather hard to recognize?
You prefer to listen to a tube amplifier then I can tell you that you CAN recognize the difference.
I need another A4 page to explain that but I will not do that for now.
- When will G2LABS release a CN II- Version for Cubietruck? I ask this because I see a benefit there in direct coupling of the I2S connection that is not available on cubieboards 1 and 2.
CN II is NOT I2S compatible it is still a spdif DAC.
Of course I2S direct from soc is the best way to do it
Therefor we have Berrynos 1541 and Berrynos mini that will be released this weekend.
Those are I2S compatible. And if you don’t want to use RPi there is other mini PCs like ITEADUINO and OLINUXINO that have I2S exposed on the header you can use for better performance.