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AK4490 USB Dac with dsd support.

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pdb

pdb

Member
Joined 2007
sonnya said:
...we bypass as much as possible in the DSD mode. (It is not possible to bypass Volume control in PCM in the AK4490)
Click to expand...
Does this mean that PCM playback suffers or is lacking compared to DSD playback? :confused: In an earlier post you also showed THD - but only with a DSD signal. For many though, it will still mostly be PCM material playing through the dac I think - also in the years to come. :) BTW will it be possible to attenuate the PCM signal in the digital domain when playing 16 or 24 bit (out of 32 bit)?
 
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sonnya

sonnya

Member
Joined 2001
mirand-audio.dk/?post_type=product
In reality, yes PCM lacks in performance compared to the DSD.

PCM Data path goes through Digital attenuator, Interpolator, Delta sigma modulator and Switched capacitor filter.

DSD normal path goes through Digital attenuator, Delta sigma modulator and Switched capacitor filter.

DSD volume bypass path goes only through Switched capacitor filter.

I am working on a firmware where the mixer is enabled. This way when you change a setting in windows software (example: Jriver), MAC OS/X (Volume up and down you can set with the keyboard) and also Volumio it will set the value in the digital attenuator.

Besides of that i will shortly release a Shield where the USB interface controls an MAS6116 in balanced configuration. This shield will have single ended output as well as balanced output. I am working on it today.
 

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sonnya

sonnya

Member
Joined 2001
mirand-audio.dk/?post_type=product
pdb said:
Does this mean that PCM playback suffers or is lacking compared to DSD playback? :confused: In an earlier post you also showed THD - but only with a DSD signal. For many though, it will still mostly be PCM material playing through the dac I think - also in the years to come. :) BTW will it be possible to attenuate the PCM signal in the digital domain when playing 16 or 24 bit (out of 32 bit)?
Click to expand...

You will see the same distortion for PCM as well.

But take a look at my post below.
 
pdb

pdb

Member
Joined 2007
sonnya said:
It does not perform worse at all. Gain is set to 0dB meaning the digital attenuator is transparant. I have put a lot of Work into use of good isolation of the voltageregulators that ultra low noise and ultra high psrr.
Click to expand...
Thanks a lot for taking the time to explain this. I just got the impression - wrongly I can see - that your DAC was aimed more at DSD than PCM playback. Sorry for all my questions - but I really struggle with the inner workings of dacs and (digital) audio :)
 
R

rogerchou

Member
Joined 2012
sonnya said:
Besides of that i will shortly release a Shield where the USB interface controls an MAS6116 in balanced configuration. This shield will have single ended output as well as balanced output. I am working on it today.
Click to expand...

I like the idea of balanced configuration. As I know DIYINHK is still setting AK4490 kit as un-balanced configuration.
The new shield will replace the SE one? Actually, I don't care you raise the price if cost is an issue. But, I wish your DAC board is fully matched with your preamp project.
 
sonnya

sonnya

Member
Joined 2001
mirand-audio.dk/?post_type=product
rogerchou said:
I like the idea of balanced configuration. As I know DIYINHK is still setting AK4490 kit as un-balanced configuration.
The new shield will replace the SE one? Actually, I don't care you raise the price if cost is an issue. But, I wish your DAC board is fully matched with your preamp project.
Click to expand...

I have no problem with you or other saying that they want the Balanced configuration instead. No matter what, if you choose to add an preamp later, the board will be fully matched.

In single ended configuration the preamp's balanced input will take the inverted signal from the GND terminal on the output stage to compensate for differences in the GND path, but signal to noise ratio will be higher with an balanced output stage of course.

Let me now how many of you want an:

1) Variable balanced output (+ singled ended) instead with MAS6116 in the path controlled by the mixer settings from the USB host.
2) Fixed balanced output (+ single ended)
3) single ended only.

I will quickly calculate the difference. The early bird will receive the Single ended output stage as well, as balanced will be a bit delayed (8 working days)
 
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pdb

pdb

Member
Joined 2007
DAC pre-order is as following:
stajo = 1
pinnocchio = 1
Press57 = 1
Myint67 = 1
rogerchou = 1
vitalica = 1
pdb = 1 (SE)

Early bird 216€ + shipping

After the 1. June 2015 236€ + shipping

Kit contains USB DAC mainboard, output shield, single ended, power cable assembly and USB Stick with Windows driver and documents
 
pdb

pdb

Member
Joined 2007
CaféNoir said:
...I find variable volume only operated by software slightly dangerous: it is easy to damage your ears by accident. Adding a physical volume control somewhere in the chain (in the form of volume knob/buttons,...) is probably safer.
Click to expand...
Agree. Once (actually twice!) I listened on headphones when suddenly there was a glitch in the playback software / driver that put white noise at full volume into my ears... it was a - how do I put it - interesting experience...! You could use both a software solution and a pot as a safety precautions if you don't have a motorized pot or an electronic / LDR volume control. I don't know how the MAS6116 solution works. Maybe it is safer?
 
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R

rogerchou

Member
Joined 2012
I am taking a long vacation right now. I respect and follow the final choice here.
Sonny, do you have any good idea at analog volume control for balanced configuration? Besides, i am a little bit confused about your preamp idea. The balanced discrete opamp output stage you mentioned above is for ak4490 dac, and then you will develop another discrete buffer with volume control IC for your preamp? So, my final solution might be ak4490 DAC with balanced discrete output stage + discrete balanced buffer with volume contro IC +V4 amp?
 
sonnya

sonnya

Member
Joined 2001
mirand-audio.dk/?post_type=product
rogerchou said:
I am taking a long vacation right now. I respect and follow the final choice here.
Sonny, do you have any good idea at analog volume control for balanced configuration? Besides, i am a little bit confused about your preamp idea. The balanced discrete opamp output stage you mentioned above is for ak4490 dac, and then you will develop another discrete buffer with volume control IC for your preamp? So, my final solution might be ak4490 DAC with balanced discrete output stage + discrete balanced buffer with volume contro IC +V4 amp?
Click to expand...

I can see it from your point of view.

If you are choosing the preamp i will make for this one, you will only need a fixed output from the DAC.

The discrete balanced buffer with volume control will be made of the MAS6116 attenuator chip. It is a thin film resistor network with CMOS switches. It was originally made by wolfson micro. It is designed to use an external opamp in this case it will be a discrete opamp.
 
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