a new multibit DAC chip Arda technologies AT1401

[Shinja]

hi

this might be a good news for multibit DAC lover.
a new multibit *not ΔΣ* DAC will be released from Arda technologies.
Arda Technologies - AT1401 Flagship Audio D/A Converter

there is not complete datasheet yet,
but reported it overcomes THD+N and DNR spec of PCM1704...

 

[tritosine]

That DA is ridiculously good. External reference, passive iv. I'll go & sign up.

 

[wktk_smile]

Seems to be designed for passive IV conversion, right?
Their ADC also seems to be good...

 

[Gluca]

Me too, signing up ... it looks like we can start with something new ... I do even have a R+xformer+tube I/V ready to roll.

 

[Joseph K]

I concur with the previous Gentlemen..

It's like all dreams coming true in one shot..

The next (real) shot will be the price?

Ciao, George

 

[abraxalito]

Certainly looks interesting - very nice to see a differential clock input to the DAC. Wonder why the ADC doesn't have that? ADC A-A filter is b*ggered up, violating Nyquist, but response looks nice otherwise - could have been a very nice part.

 

[qusp]

meh, you guys can keep your passive IV. very cool that you can finally play around with a chip that is still in production though. I like the sound of the AT1525 cleanup phaselock loop chip. i'm going to keep an eye on it, because it does sound quite intriguing and a fresh way of doing things.

option for external reference is good, hardly unique though

 

[abraxalito]

I think its not 'still in production' rather 'still to be produced' as they're inviting input into the feature set.

 

[qusp]

not sure why you corrected me there. I realize that, I read the copy, seems they are pretty far along, was just making the distinction between it and the usual NOS of sometimes dubious origins

 

[tritosine]

Nice coincidence at some other diy forum, lol:

Most users ever online was 125 on Sun Jan 30, 2011 2:18 am

 

[Gluca]

Signed up and I requested a couple samples. I was thinking to a CS8422 + AT1401

 

[SoNic_real_one]

Indeed impressive specs. I am curious if they will deliver.
OS capability is great and an I/V stage with fast OpAmps (LT1807, LT6200 ?) should be all right.

 

[abraxalito]

Indeed impressive specs. I am curious if they will deliver.

Me too - I can't see a market for a custom chip especially targeted at the passive I/V crew myself. The volume just does not seem to be there. I signed up though, we'll see.

 

[SoNic_real_one]

If we get some samples, maybe we can design a PCB board and a group-buy...

 

[abraxalito]

... an I/V stage with fast OpAmps (LT1807, LT6200 ?) should be all right.

No, I wouldn't recommend LT6200 in I/V duty. I've found that opamps designed for low noise are more susceptible to RF - they don't give good sound without a lot of circuit tricks. LT1807 is better, at 3.5nV, but still would need careful feeding. Since the signal levels are so high in I/V, low noise isn't a primary requirement.

 

[SoNic_real_one]

It't all in S/N ratio. At 2V maximum output, to get the -120dB you need an equivalent input noise of 2uV... I think that translates to a maximum 5nv/sqrtHz...isn't?

 

[abraxalito]

Well its the output where we measure the SNR. So let's see, if we want 120dB SNR and the bandwidth is say 40kHz (assuming we're running at 96kHz) then that's 2uV in sqrt(40000) which comes out at 10nV/sqrtHz by my estimation. In an I/V, the opamp is operating at unity noise gain typically - its effectively a follower noise-wise. That is assuming that the DAC's output impedance is high relative to the feedback resistor used and its output capacitance isn't high enough to raise the noise in the audio band.

We can add another 3dB when the DAC's being used to generate a balanced output as the signal will be correlated but the noise not. -123dB noise floor is fairly unlikely to be found on any real-world recording btw - the noise floor of 16bit/44k1 is around -93dB, depending on the dither used.

 

[SoNic_real_one]

I like to have some headroom for the I/V resistor noise and for the one originating in the DAC ladder/curent supply... If I can minimize one influence (OpAmp noise), why not?
I think anything below 3.5uV/sqrtHz should be all right.
And yes, I am thinking at 24bit/96kHz sources, not necesarly CD's. After all, 120dB means "only" 20bit resolution.

 

[JarekC]

Hello,

I anybody get information from ARDA about sampes and chip availability?

Best Regads
JarekC

 

[Gluca]

They said me that the chips will be available later this summer