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

- use only any one ground connection and not three or four against each Data, BCLK, etc.

Yes! And also remember might be yet another GND connection via the power supplies of the DDDAC and the RPI+HifiBerry (if both power supplies are connected to the same GND). Adding a dedicated GND wire at the I2S pins will therefore create a ground loop. I have to say that this ground loop is not an issue in my case, and I do have a dedicated GND wire between the HifiBerry and the DDDAC.

- Don't solder these wires

That's interesting one! I don't doubt your observation, but it would be interesting to understand what's going on.

- In case you are not using Moode, try using that.

Nothing wrong with MOODE, but Volumio will be totally fine to get a clean I2S signal.
 
Since i2s is a sensitive connection, maybe soldering exposes some type of connection and hence grounding is a problem or maybe... I am not an electronics person so ignore if this does not makes sense. But it is my practical observation and i tried doing this multiple times and got crackling noise every single time.
 
Why not run everything else through the transformer volume control, too? Ok, it would be a bit of work to build a chassis with a selector switch and stuff, but a transformer volume control really is a good thing. I stopped using conventional resistive attenuators, because they basically "burn" must of the music signal to reduce the amplitude :eek:

Indeed optimum solution - I have the "special dddac" Sowter with 18 taps at the secondary. I use my own built remote control (arduino) and 18 relais to select the taps. Indeed somewhat more work, but an excellent solution.

Frequency response straight line 20Hz to over 200k (my AP stops at 200kHz :eek: ) and only 10 degrees phase shift at 200kHz and 20Hz
 

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Why not run everything else through the transformer volume control, too? Ok, it would be a bit of work to build a chassis with a selector switch and stuff, but a transformer volume control really is a good thing. I stopped using conventional resistive attenuators, because they basically "burn" must of the music signal to reduce the amplitude :eek:

My preamp has a TVC already at the output of a 301a tube and it works very well!
 
The noise problem is solved. Unfortunately I only figured out the requirements and limitations of the DDDAC Pi combination once I had it on my bench and in my specific case that appliance is completely useless. I got a € 25 AptX Bluetooth thingy that does everything I was looking for without any hassle and without any noise issues.
The DDDAC is sold, it was a waste of time and money.
 
The noise problem is solved. Unfortunately I only figured out the requirements and limitations of the DDDAC Pi combination once I had it on my bench and in my specific case that appliance is completely useless. I got a € 25 AptX Bluetooth thingy that does everything I was looking for without any hassle and without any noise issues.
The DDDAC is sold, it was a waste of time and money.
If you can't tell the difference between a Euro 25 Thingy and a properly set up DDDac then you are right: it's a waste of time and money for you and the money's better invested in hearing aids
 
update on my DDDAC

Hello,
My DDDAC is back in the audio rack at the level of my head. I thought it would be lighter after removing the big transformer and the little choke and replacing them by a small transformer and a BIG choke. But it was similar maybe i didnt check its weight for a long time. BUT this morning it was 30,9 kilogrammes. Putting it in the rack was always a big task not so much because of the height but the limited space available AND the use of sorbothane dampers. What i do know is using 2 wooden bars and slide the dddac inside the rack. After that i use an inflatable cushion, pump it up, put the sorbothane dampers( the one that looks like half a tennis bal) in the right spot and then let the air escape. Works flawlessly because when the sorbothane are attached to the DDDAC in a permanent way you cannot slide it. Have to create some clearance and that is hard when there is only 5 centimeters in height extra available in the rack.
I replaced the frontplate with another stainless steel one and installed a very old panelmeter ( moving iron) to indicate the voltage going into the main print.
Now i will first finish some other things before modifying the DDDAC again.
First modification will be changing the Belleson 5 volt 2A supply for the wave IO. Right now it is choke input but i wanna try to use the 0,5 A LL2771 here.
I checked the voltage on that supply to find out what transformer i will need. When just thev wave IO is being fed by the power supply , so no signal connected will it still take 385 mA ? Right now the input of the Belleson is around 10,5 volts. Maybe i wanna change it into superteddyreg.
As you can see there is still some space left.
In the future i wanna switch to i2s gear but i still have my Aurender.
They say switching from usb to i2s is worth the trouble. The parts needed in the dddac are moderately priced but the strwamer sold by Audiocreative is not to cheap after already having bought the Aurender.
Greetings, Eduard
P.s i think in a few weeks time i will have two LL2733 1 Henry 0,7 A for sale. I used them as the second choke in a LCLC supply for 1A load. Not sure if they can take 1A when used as input choke. Because the maximum ripple is 120 volts for them they can take extra current when ripple is much lower as in DDDAC use
 

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The airgap of the choke is set for a current. The amount of AC doesn't matter. Check the Lundahl datasheet for "recommended dc current" and "saturating current". Stay clear of saturating the core. If you wonder about the current draw of the Wave IO just measure it.


If weight is an issue remove the mains transformers, rectifiers and first LC and put them in an external case. That way the only AC in the signal part is the audio signal.
 
Hello,
Someone tell me something i dont know.
OF COURSE the amount of AC does matter. Check the Lundahl datasheet!!!
I know the WAVE IO takes around 385 mA. But i thought it only does when there is an audio signal present and it is connect to the mainboard because one of the 5 volt supplies it needs actually comes from the mainboard.
I alrerady figured it out that moving heavy parts outside the chassis will reduce the weight. Doede told me his kind of circuit isnt very sensitive regarding the use of chokes nearby because it is low impedance.
greetings, Eduard
 
My LT-3045 adventure has come to an end. 5v on WaveIo’s input and 12v on input mainboard. Best sound so far. I think that the two 5v regs on WaveIo’s input and I2s isolated has most impact on the sound quality. The 3.3v regs on the dac boards digital side are very hard to tell if there is any improvement at all. I think doede is right here.

So my advice is to change the two 5v regs on WaveIo input and I2s isolated side.



Quoting myself.

Almost one month since the regulator upgrade and I just want to say that this upgrade is a no brainer. The regulators add clarity and dig deeper into the recording. The music sounds simply more involving, and the listening window is expanding with better 3D.
 
Hello,
Some LL2771 will arrive in a week or two.
I can imagine that a serie regulator followed by a shunt regulator like the 8 volt supply on the little dddac boards will give the best of both worlds.
But putting two serie regulators in series sounds like a bit strange to me or not?
The 7810 is like a kind of preregulation AND to protect the shunt from a to high voltage which could fry them.
I have been using the Allen Wright designed shunt supply which uses a 317 ic on the input side and later Allen came up with a modification using two calculated resistor instead of the 317 which removed some '' glare '' from the circuit.
So i understand not all regulators sound the same.
Right now using the Belleson for the wave IO. Going to change its choke input filter with a bigger choke and then probably going to try some other regulators. I wish Guido would make a shunt for the wave io too.
Greetings, Eduard
 
My setup from listening position. Dddac at the bottom.

Hey Smooth Dancer,

thanks for feedback on the regulator topic - May be during Summer break I can try this - Easy tweak which is fun of course :cool:

and now a bit off topic. I saw your equipment image (nice stuff by the way) and thought, wow we totally individually from each other have similar solutions for the Audio Rack, Mediaplayer and the "Dust cover" for the turntable :umbrella: ;) I assume you build them also yourself?

best
doede
 

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Hi Doede

Yes, I have built the rack and amp and speaker stands.

You MUST try the regulator tweak, especially the two 5v regs for WaveIo.

In my opinion the sound from Aurender-WaveIo-DDDac is so far the best I have tried. I have also tried Odroid directly to dac, and this was very impressing to begin with, but after a while the listening fatigue sat in.
 
Hi Doede

Yes, I have built the rack and amp and speaker stands.

You MUST try the regulator tweak, especially the two 5v regs for WaveIo.

In my opinion the sound from Aurender-WaveIo-DDDac is so far the best I have tried. I have also tried Odroid directly to dac, and this was very impressing to begin with, but after a while the listening fatigue sat in.


Can you explain what the exact change is please as I want to try it?

Thank you