I just want to give an warning about Volumio.
Volumio will during boot send out DC through DSD. And it is not only zero's or one's so that AK4490 can detect it as DC.
Through Windows, Vortex box and MAC OS/X this is not the case. Then it all works just fine.
I have posted a bug report to Volumio but no one has reacted on it!??
The link: https://volumio.org/forum/strange-problem-during-boot-until-first-played-song-t3212.html
This DC is present until the first music plays. After that there is no problem at all.
Volumio will during boot send out DC through DSD. And it is not only zero's or one's so that AK4490 can detect it as DC.
Through Windows, Vortex box and MAC OS/X this is not the case. Then it all works just fine.
I have posted a bug report to Volumio but no one has reacted on it!??
The link: https://volumio.org/forum/strange-problem-during-boot-until-first-played-song-t3212.html
This DC is present until the first music plays. After that there is no problem at all.
Update on the buy list.
stajo = 1 (Paid) (Shipped)
pinnocchio = 1 (Paid), 1 Softstart (Shipped)
Press57 = 1 (Paid) (Shipped)
Myint67 = 1(withdraw from early bird ) (will receive later)
rogerchou = 1 (Paid) (Shipped) (Today)
vitalica = 1 (Paid) (Shipped) (Today)
pdb = 1 (SE) (Paid) (Shipped)
burninggecko = 1 (SE) (Paid) (Shipped)
MisterRogers = 1 (SE) (Paid) (Shipped)
Catal = 1 (SE) (Early bird) (Shipped)
Ravid = 1 (SE) (Paid) (Shipped)
stajo = 1 (Paid) (Shipped)
pinnocchio = 1 (Paid), 1 Softstart (Shipped)
Press57 = 1 (Paid) (Shipped)
Myint67 = 1(withdraw from early bird ) (will receive later)
rogerchou = 1 (Paid) (Shipped) (Today)
vitalica = 1 (Paid) (Shipped) (Today)
pdb = 1 (SE) (Paid) (Shipped)
burninggecko = 1 (SE) (Paid) (Shipped)
MisterRogers = 1 (SE) (Paid) (Shipped)
Catal = 1 (SE) (Early bird) (Shipped)
Ravid = 1 (SE) (Paid) (Shipped)
Pinniocchio has made an review on his website it is in french but you can translate it with google translate.
The review is in
Mirand Audio AK4490 DAC DSD
The review is in
Mirand Audio AK4490 DAC DSD
Thanks for the info. Have a real nice and relaxing Holiday. You truly deserve it
All the best, Per
Hello, i am back.
Just some update on the shield. The opamp modules are assembled..
As you all can see it is very compact.
It is true folded cascode, with jfet input pair 2SK2145-BL.
It runs from around +/-15VDC
But at is right now. I have started on the shield layout with the use of my opamp modules. I will upload info this evening.
But i have also two frontpanels on completion.
After the shield i will shortly after make the preamp sections using the discrete opamps.
Just some update on the shield. The opamp modules are assembled..
As you all can see it is very compact.
It is true folded cascode, with jfet input pair 2SK2145-BL.
It runs from around +/-15VDC
But at is right now. I have started on the shield layout with the use of my opamp modules. I will upload info this evening.
But i have also two frontpanels on completion.
- One with LED for source format, and one filter select button. Very simpel.
- One with OLED display, buttons and IR input.
After the shield i will shortly after make the preamp sections using the discrete opamps.
Attachments
I have been looking onto different types of analog filters.
The PCM filter that they suggest in the datasheet is an butterworth type with an Q of 0.704.
I will change it to an bessel. It is only R and C values that will change.
Gain will be -1.5dB, phase @ 20KHz will be 17 degrees instead of 18 degrees. Q will be a lot lower 0.5771. So the step response will be better as we have an constant group delay and a linear phase response.
Also the shield has space for 3 opamps per channel.
IF you only want to go single ended discrete then only one per channel is needed.
IF you only want to go balanced discrete then two per channel is needed.
IF you only want to go balanced and single ended discrete then three per channel is needed.
The PCM filter that they suggest in the datasheet is an butterworth type with an Q of 0.704.
I will change it to an bessel. It is only R and C values that will change.
Gain will be -1.5dB, phase @ 20KHz will be 17 degrees instead of 18 degrees. Q will be a lot lower 0.5771. So the step response will be better as we have an constant group delay and a linear phase response.
Also the shield has space for 3 opamps per channel.
IF you only want to go single ended discrete then only one per channel is needed.
IF you only want to go balanced discrete then two per channel is needed.
IF you only want to go balanced and single ended discrete then three per channel is needed.
Good idea. It is much flexible for us. Is the preamp same design for us to choose balanced or SE or both?
Jfet folded cascode amp measurements.
We have measured on the discrete opamp. Normally folded cascode does not have high open loop gain, but we managed to pull out and THD+N of close to -110dB with 2x gain (2K + 2K) and 4Vpp at 1KHz.
DC offset is only a few mV.
See the FFT signal i have attached. Below 1KHz there is some pins but it is 50Hz and harmonics of it.
BR Sonny
We have measured on the discrete opamp. Normally folded cascode does not have high open loop gain, but we managed to pull out and THD+N of close to -110dB with 2x gain (2K + 2K) and 4Vpp at 1KHz.
DC offset is only a few mV.
See the FFT signal i have attached. Below 1KHz there is some pins but it is 50Hz and harmonics of it.
BR Sonny
Sonny has extended the TSSA V2 early bird till the end of this week (29) Read more on the V4/V8 thread about specs and sound
Filter settings firmware for AK4490 USB Audio DAC V1.0
Hello The attached zip file includes 5 sets of binary files to load onto the DAC.
To upload them to the DAC you have to use the windows driver supplied on the USB stick.
The driver will be installed under c:\programs\XMOS\USBAudioStDriver_305C
In this folder there is an program called xmosusbaudiost305C_dfuapp.exe
Unzip the files in an folder.
Connect the DAC, start the xmosusbaudiost305C_dfuapp program.
It will find the DAC.
Then select "browse" button and find the file you wants to upload.
Then press "Start" button.
Thats it! Enjoy it and let us hear what you all think.
BR
Sonny
Hello The attached zip file includes 5 sets of binary files to load onto the DAC.
To upload them to the DAC you have to use the windows driver supplied on the USB stick.
The driver will be installed under c:\programs\XMOS\USBAudioStDriver_305C
In this folder there is an program called xmosusbaudiost305C_dfuapp.exe
Unzip the files in an folder.
Connect the DAC, start the xmosusbaudiost305C_dfuapp program.
It will find the DAC.
Then select "browse" button and find the file you wants to upload.
Then press "Start" button.
Thats it! Enjoy it and let us hear what you all think.
BR
Sonny
Thank you Sonny. Eagerly looking forward to being able to listen to your dac and evaluate the different filters.
OUTPUT Shield DIFF/SE V1.0 Discrete
Hi.
Just an update.
The Shield takes form now. It is an 4 layer board. Each opamp uses around 40mA. So this board need +/-15V and 300mA (The optocouples uses a bit )
The board has the same size as the DAC mainboard.
There is no relay on this one. It is replaces by SSR with very low RDS on and very low QR for minimal insertion loss of sound quality. Less than with relay, and no clicking as well...
It is laid out now, so we need to route it and put it into production.
The opamps are identical to the ones used in the TSSA V2/V4 and V8 control which works very well.
>220 components on this one!
BR
Sonny
Hi.
Just an update.
The Shield takes form now. It is an 4 layer board. Each opamp uses around 40mA. So this board need +/-15V and 300mA (The optocouples uses a bit
)The board has the same size as the DAC mainboard.
There is no relay on this one. It is replaces by SSR with very low RDS on and very low QR for minimal insertion loss of sound quality. Less than with relay, and no clicking as well...
It is laid out now, so we need to route it and put it into production.
The opamps are identical to the ones used in the TSSA V2/V4 and V8 control which works very well.
>220 components on this one!
BR
Sonny
Frontpanel Design.
For the frontpanel we will get this button made from aluminium or steel.
It is made for an 8mm front. It is running in an nylon bush to give a smooth feeling.
For the Encoder we will make an volume button in similar design.
On request we will do a frontpanel. But we have to know how many is interested in this.
Preamp Design
The preamp will use same discrete opamps as the DAC output shield. So this is not far away as well.
BR
Sonny
For the frontpanel we will get this button made from aluminium or steel.
It is made for an 8mm front. It is running in an nylon bush to give a smooth feeling.
For the Encoder we will make an volume button in similar design.
On request we will do a frontpanel. But we have to know how many is interested in this.
Preamp Design
The preamp will use same discrete opamps as the DAC output shield. So this is not far away as well.
BR
Sonny
OUTPUT Shield DIFF/SE V1.0 Discrete done!
Hi, The new output shield is now done.
It will be ready to ship within 2 weeks.
The shield alone will cost 167,5€ + shipping.
An combo pack with the USB DAC mainboard 326€ + shipping.
Early bird on this one is:
The shield alone will cost 147,5€ + shipping.
An combo pack with the USB DAC mainboard 306€ + shipping.
It is fully discrete. 71x110mm
Filter components is thin film resistors in 0805 layout 0.1% 25ppm and capacitors is PPS also in 0805 and 2%
And output relay is replaced by ultra low distortion SSR switches.
The odd shape is because of USB and connectors on the mainboard
BR
Sonny
Hi, The new output shield is now done.
It will be ready to ship within 2 weeks.
The shield alone will cost 167,5€ + shipping.
An combo pack with the USB DAC mainboard 326€ + shipping.
Early bird on this one is:
The shield alone will cost 147,5€ + shipping.
An combo pack with the USB DAC mainboard 306€ + shipping.
It is fully discrete. 71x110mm
Filter components is thin film resistors in 0805 layout 0.1% 25ppm and capacitors is PPS also in 0805 and 2%
And output relay is replaced by ultra low distortion SSR switches.
The odd shape is because of USB and connectors on the mainboard
BR
Sonny
