Another Discrete R2R Multibit Dac that can do DSD, again from the land of the Great Wall

Digital is a totally different animal to analog, like Ying and Yang. I've got no problems with I/V and output stages in dacs and cdp's. But the 0 and 1's side of things leave me cold.
Cheers George 

George I'm curious, what would be your preferred method of I/V  and output stage circuit if you were to design a DAC?
Charles,

An I/V passive resistor is very tempting, but the trouble is it knocks down the output of the dac so much the amplification after it has to be huge and that means so is the noise. I/V transformers sound too colored to me. Both of these suffer in the dynamic department.

I prefer this I/V stage thread I started, zero feedback and very high slew rate I/V, 3 -4 stacked, so the input impedance comes down to around 10ohms, and the current handling goes up, so there’s no current limiting as happens with a single one.

http://www.diyaudio.com/forums/digital-source/227677-using-ad844-i-v.html
(go to page 17 mid way down) that’s where it starts getting interesting with the stacking of these I/V stages.

As far as the buffer, good clean low output impedance with good current output, discrete or opamp based I’ve used both on this thread and reported their sounds with this I/V stage.

At the moment I also have a Linn CD12 v2 here, which uses similar I/V but with 4 X PCM1704’s and it is very good on PCM 16/44 and 24/96 replay.

Cheers George

Thanks for your informed response George, I appreciate it. My DAC takes the approach of a single resistor for I/V conversation. It is but only one of several suitable methods but it surely sounds very good as implemented.  I will read the thread you cite. 
Charles,

For multiple stacked implementation of R2R chip, do take a look at this website,  www.dddac.com . It allow you to stack as many R2R as you like and it comes in diy modules. Some basic knowledge of electrical and soldering skills needed though. However,  from the diy community, the results from this dac are overwhelming,  the more stack you use, as much as 16 (4 levels high)  the better the sound. The audio performance always improve by using more and more R2R chips! 
-phil