Are you sure about the 4495's DC offset? According to its datasheet it should have the same offset that the 4490 has (VDDx/2).
This is from ak4495 datasheet.
"The AK4495S/95 is a 32-bit DAC, which corresponds to high-performance, high sound quality digital audio systems such as DVD-Audio and BD. An internal circuit includes newly developed 32-bit digital filters for better sound quality, achieving low distortion characteristics and wide dynamic range. The AK4495S/95 has full differential SCF outputs, removing the need for AC coupling capacitors and increasing performance for systems with excessive clock jitter. The AK4495S/95 accepts up to 768kHz PCM data and 5.6MHz DSD data, ideal for a wide range of applications including Network Audio and SACD."
... removing the need for AC coupling capacitor ... You will not find this statement in ak4490 datasheet.
I tried connecting ak4495 and ak4490 to my tube buffer. Only ak4495 worked. Besides dc Offset could easily measured.
That is odd. Looking at Fig. 39 in page 57 we can see DC blocking caps.
Plus the 4495's datasheet says: "The analog outputs are full differential outputs and 2.8Vpp (typ, VREFHL/R VREFLL/R = 5V) centered around VDDR/2 and VDDL/2 voltages." which is exactly what the 4490's datasheet says.
But if you are measuring no DC offset (WRT ground) I can't argue with that.
Plus the 4495's datasheet says: "The analog outputs are full differential outputs and 2.8Vpp (typ, VREFHL/R VREFLL/R = 5V) centered around VDDR/2 and VDDL/2 voltages." which is exactly what the 4490's datasheet says.
But if you are measuring no DC offset (WRT ground) I can't argue with that.
So datasheets are confusing. I did not measured dc offsets. I assumed it based on what was in datasheets plus my successful connection of ak4495 to tube buffer and unsuccessful connection of ak4490 to the same buffer( ak4490 gave very distorted sound). If it was today I would obviously measured it.
Hello,
I'm not sure it is the right place to post this but since there is already so many info on AK4490 I take my chance.
I plan to build a JLSounds AK4490 DAC (DAC+I2SoverUSB+LME49710 filter) and use the 0.8uV Ultralow noise PSU from DIYinhk (one for 2x5V and one for +-15V).
I was wondering if there is any upgrade I could easily do ?
For the opamp I understood that AD4898 was a good replacement for the LME49710, is there other candidates I chould try ?
For the transformers, R-core are a better choice than donnut form, am I right on this ? And are those value good : 2x7V and 2x12V (for the 2x5V and +-15V output) ?
Thank you a lot in advance !
I'm not sure it is the right place to post this but since there is already so many info on AK4490 I take my chance.
I plan to build a JLSounds AK4490 DAC (DAC+I2SoverUSB+LME49710 filter) and use the 0.8uV Ultralow noise PSU from DIYinhk (one for 2x5V and one for +-15V).
I was wondering if there is any upgrade I could easily do ?
For the opamp I understood that AD4898 was a good replacement for the LME49710, is there other candidates I chould try ?
For the transformers, R-core are a better choice than donnut form, am I right on this ? And are those value good : 2x7V and 2x12V (for the 2x5V and +-15V output) ?
Thank you a lot in advance !
You can try diyinhk ak4497 board instead of ak4490.
As opamp you can try some of the discrete replacement e.g.: from silabs.
You can try O-Core (not toroidal!) from jamestransformer instead of R-Core
Use Salas Ref-D regulator instead of diyinhk 0,8uV or use Salas Ref-D as prereg for those from diyinhk. Low noise is not everything. Transient response, low impedance and broad bandwith are also factors that does matter in audio.
I2SoverUSB is based on old xmos chip. Diyinhk uses newest one (xmos2016) with digital volume control!
So pretty much you can upgrade everything
Last edited:
You can try diyinhk ak4497 board instead of ak4490.
As opamp you can try some of the discrete replacement e.g.: from silabs.
You can try O-Core (not toroidal!) from jamestransformer instead of R-Core
Use Salas Ref-D regulator instead of diyinhk 0,8uV or use Salas Ref-D as prereg for those from diyinhk. Low noise is not everything. Transient response, low impedance and broad bandwith are also factors that does matter in audio.
I2SoverUSB is based on old xmos chip. Diyinhk uses newest one (xmos2016) with digital volume control!
So pretty much you can upgrade everything
Hello TioFrancotirador and thank you for your reply.
About the diyinhk board I read (at the first release of the AK4490 so a long time ago) that the board had click noise. Also that the reconstruction filter was nos very optimized.
Then I really prefer the screen of the JLSounds and above all, the menu and settings ; the diyinhk seems to let you choose only from 4 filters (instead of 5) and seems to lack the DSD direct mode. My goal is to use HQplayer and run many tests with different settings... I don't really mind the volume control.
For all those reasons I chose the JLSounds, but maybe I am wrong or those things have been corrected ...?
For the Salas Ref-D I would be glad to give it a try but the GB seems to be over
I will definitely check on the O-Core from jamestransformer.
Thanks again for your help !
----EDIT----
PS : Why is O-core preferable to R-core ? Thx
Last edited:
Hello TioFrancotirador and thank you for your reply.
About the diyinhk board I read (at the first release of the AK4490 so a long time ago) that the board had click noise. Also that the reconstruction filter was nos very optimized.
Then I really prefer the screen of the JLSounds and above all, the menu and settings ; the diyinhk seems to let you choose only from 4 filters (instead of 5) and seems to lack the DSD direct mode. My goal is to use HQplayer and run many tests with different settings... I don't really mind the volume control.
For all those reasons I chose the JLSounds, but maybe I am wrong or those things have been corrected ...?
For the Salas Ref-D I would be glad to give it a try but the GB seems to be over
I will definitely check on the O-Core from jamestransformer.
Thanks again for your help !
----EDIT----
PS : Why is O-core preferable to R-core ? Thx
Above all proper powering is most important.
Click noise in diyinhk is eliminated by powering xmos not from PC but externally.
If you are so into DSD and want to use HQPlayer then I would go for amanero and DSD passive conversion. Check "Mshow Differential DSC1 DAC decoder DSD Assembled Compatible w/ Amanero or XU208" on ebay.
The best place for volume control is at the dac. akm4490 has bit perfect volume control.
Transformer should be before the buffer, as it eliminates DC, unless your buffer eliminates DC then transformer might be unnecessary.
The wiring I use is just transformer. No additional caps and resistors.
As for the volume control you can refer to here:
768kHz/32Bit AK4497EQ DAC, I2S/DSD input - DIYINHK
Why do you need buffer anyway?
Volume control in all of these DAC chips is done in the digital domain so there has to be at least some loss in resolution, but since the processing is done with 32bit accuracy the loss is extremely small.
There is no such thing as "bit perfect volume control", since there is always digital processing involved so bits have to be dropped.
There is no such thing as "bit perfect volume control", since there is always digital processing involved so bits have to be dropped.
ok, that's what i thought.
I have a Ian Canada Multi-Channel FIFO + Multi-Channel DualXO then i attack the DAC directly in I2S.
My original idea, for 3 active channels, is to use AK449x DAC + LDR volume Control by Arduino (i have one in 1 channel configuration and it works very well) + Buffer (to achieve good impedance between volume control and amplifier).
But if i can have a good volume control directly in the AK449x, i can reconsidered my opinion...
For that i need to find a solution with 3 DAC boards (I2s input) and 1 control volume for the 3 boards. I did not find.
Perhaps i can use dimdim arduino code but i need to manage CAD0 and CAD1 on the DAC board. I just have to find the right board...
nounouchet
I've designed and built this board: http://www.diyaudio.com/forums/digi...-arduino-controlled-dual-mono-ak4490-dac.html
But it too is not "multichannel friendly".
But it too is not "multichannel friendly".
- Status
- This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.