A good way to reduce R-2R DAC linear error

[AD1865]

I have used AD1853

I don't think AD1853 as good as PCM1704. PCM1704 gives the emotion in music but AD1853 only play the music. Maybe PCM179X is much better than AD1853? The advantage of Delta-Sigma DAC in sound is softness, but can't express emotion in music like R-2R dac, so I like R-2R better.

 

[Ulas]

One 20 or 24 bit DAC chip per bit.

Assuming that the DAC has parallel input:

We need only a binary counter that is connected to an encoder.
And turn the wheel until the output voltage matches the theoretical output voltage of "Bit 1 on" as good as possible.
The corresponding code is the fixed code, the first DAC will always see when bit 1 is "on".
We take a new DAC chip and turn the wheel until the output voltage matches the theoretical output voltage of "Bit 2 on" as good as possible.
The corresponding code is the fixed code, the second DAC will always see when bit 2 is "on".

And so on...

Bernard,
Whereas the sign-magnitude architecture of the PCM170x is intended to minimize the zero-crossing glitch, your proposed DAC-per-bit will maximize it. A very small signal swing, from 0 to –1, for example, will result in a significant glitch and maximum settling time. I’ve modeled settling time and found it does more damage to the signal than a comparable amount of jitter. Furthermore, I wouldn’t worry about absolute linearity because every audio sample already has a theoretical error in the range of +/- 1 LSB. The actual error in each sample of a well-produced audio CD is more like +/- 2 LSB.

 

[jan.didden]

Re: I use best DAC

WM8768? why not use PCM1792/4? IMHO, Delta-Sigma DAC is not better than R-2R dac in sound quality, although its spec is better.
To Bernhard, using 4 pcm1702 for balance is enough, And to validate if only need to test 38 code for each PCM1702.

Well, I thought, going from 32 x PCM1702 to 4 times WM8768 would be more economical. You probably save 200 $ on PCB area alone 😉 .

Now of course there are many that will cry that it ****** up the sound, but that's in the ear of the beholder, isn't it?

Jan Didden

 

[Bernhard]

😕 😕 😕