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AK4490 USB Dac with dsd support.

Dear Anthony,

Be careful, J11 is the connector for the external power supply..

And it works only if you disconnect the onboard DC-DC converter before!

The reason is more "mental" than objective..
Sonny had separated nicely the two circuit domains with his galvanic isolation scheme.
One is the "dirty" USB & usb receiver part, the other is the clean power part containing the dac chip & auxiliary services (microcontroller) plus the clock oscillators with relative low noise power supplies. This clean part is completely isolated by the use of a series of isolator chips.
But.
The original dac structure consisted of: two high voltage power supplies (+_15V) and ! One low voltage PS, 5,5V.

Now he wished to stay backwards compatible (so users can fot the new dac module into existing setups..)
So he had to use only one digital supply, 5,5V , for both the clean and the ' dirty' side.
What he did is applying this dcdc converter module, which tranfers power to the dirty USB side, while maintaining still the galvanic isolation.

Now, his choice apparently works. I could not show a "negative effect" in measurements, while it was clearly visible that this new setup gives a better measured result than the original V1.0 module.
That is, removing the dcdc converter, and supplying an external 5V digital supply directly to the 'dirty' USB side by the use of J11 - give only very similarly good, loe noise low distortion results like before.

But I think to have heard an opening up, more freedom in the sound. I have written here my impressions, it was quite a time ago. Since then obviously only listened to the separate solution.

All the best, George
 
The supply: i have used a completely separated, independent secondary (~6V) linesr supply, with good quality diodes and caps; then a ADM7150 based (diyinhk) 5V regulator.
Though.. in theory it should be innocent, non influential, this "dirty side" supply quality.
Guess what... one can still hear differences..

Go figure.. ciao, George
 
Hello everyone,

I'm using HQPlayer to up-sample everything to DSD 128/256. I stream it to Allo USB Bridge (HQ Player NAA) connected to USB 1.2 DAC. This is one of the best DAC in my opinion.

However there is a niggling issue. On powering up the DAC and playing DSD I get a buzzing sound all the time. To fix the buzzing sound say if default filter is at F2 I need to change the filter from F2 --> F3 and may be to F0 and then the music starts coming. Once I do the above routine on power up, the DAC works fine in any mode and any filter till I power it down. If I power it up again I have to follow the routine of changing the filters for the DAC to pick-up the correct DSD resolution. It doesn't happen while playing PCM.

Any idea how I can fix the above niggling issue? I've USB DAC 1.2 with Simple front panel and I'm running firmware version # 01.
I posted this issue 8 months ago but didn't get any help. Just wanted to check if others were able to play DSD using HQPlayer/Roon without the issue I mentioned.
 
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At a certain time I had the same feature.
Now I would have to turn it on to be sure..

If you can at least check your firmware version that would be great. If using Simple Front Panel you need to navigate to Menu --> P0 --> Center button on apple remote to know the version.
By the time I received my DAC and set it up the firmware Sonny shared in this thread has been deleted. I was just wondering if there is a fix in that firmware he shared which I couldn't download.

Very interesting! Wanted to go the same direction..
Could You tell more!? About the difference...

I see from your previous posts you were already using HQ Player. When I wanted to try HQ Player I straight away bought an Allo - USBridge with diet-pi seeing the reviews. It's just plug and play, comes with most of the stuff loaded like HQP NAA, Roon Bridge etc. I haven't tried any other single board computer to compare it to.

For me the only benchmark is the HQPlayer set-up with Sonny's DAC + Discrete Output stage beats CD/SACD playback on my marantz sa8005 sacd player in every area. Also I'm able to use some room correction too with HQP.
 
George,. Allo usbridge sound is fantastic if you feed it with a good supply.. Just the os software can be a pain..the os like to lose detection of the usb port every few weeks and you have to load back from backup

I tried programs including naa audivarna. Until I found miminserver to run soxr resampling. Simply stream in to any dlna upnp and its a dream to run. Excellent sound Sq using a odroid hc2. Feed it using a decent supply too. I use just a mobile phone running bubbleupnp

A simple conclusion... About music server, dac and steamer.

1. Clock quality everywhere and I mean everywhere
2. Low to moderate tdp. The higher tdp the worse sound.
3. Good supply everywhere

I'm using only printer cable, generic Lan cable and it already sounding great.

Split the supply of digital, Using lt1963 using another core. Added isolation seems to improve sound some. While using salas reflector d for main 5.6v for colour
Improve analog, detail weight. Depth and width.

It's a pain with the discrete output pin.. It got to sit perfectly or will lose sound or gain

Great fun with this diy project nonetheless. Keep your interesting post.. Love to see those ideas comming.