Denafrips Terminator R2R Multibit, ultimate pcm redbook converter??

@teo_audio

Just because there are many bad sounding (screeching as you put it) Delta Sigma DACs does not mean that none of them are any good.

The latest Delta-sigmas use multiple 1 bit converters to achieve the same as a 6 bit R2R DAC. You can understand how a ladder DAC takes output from a resistor network where a small number of resistors are exact multiples of each other (1x,2x, 4x, 8x etc). Well you can also build a network from the SAME 1x resistor but simply by using a huge number of them. This is in effect what new Sabre Delta Sigma DACs do - 64 x 1 bit DACs - and by summing them to various degrees you get up to 6 bits.

So the line between R2R and Delta Sigma is blurred when you realize that the latest Delta Sigma chips are behaving much like an R2R DAC (but only a 6 bit one). The end result is that the latest Delta Sigma DACs are extremely linear (benefit of 1 bit) and yet they also do not need to upsample nearly as much as older generation pure 1 bit DACs (without a 64 array).

Of course an R2R DAC can be designed to be NOS however this is at the expense of linearity (THD) performance.

Since multibit DACs have great low noise but poor linearity and the 1 bit DACs have excellent linearity but high noise NEITHER are purely the best approach - the 6 bit DAC with some oversampling is currently achieving the best performance.

More explanation here of how one designer has approached the challenge of noise and linearity.

https://benchmarkmedia.com/blogs/application_notes/inside-the-dac2-part-2-digital-processing

Furthermore, as this manufacturer states 90% of the circuitry and the major part of DAC performance is all in the ANALOG design (so according to manufacturer much of the performance is NOT even related to Multibit R2R NOS vs Delta-Sigma digital conversions)

https://benchmarkmedia.com/blogs/application_notes/149341191-inside-the-dac2-part-1-analog-processin...

Conclusion (if you buy this line of reasoning): It is far far more important how well the DAC is designed and built than the specific digital conversion chip employed (1704, 9018 etc)!!!!!!!

Excellent sounding DACs do not ALL have to use the same exact methodology and there is more than one way to skin a cat.

@kclone

It depends on the particular DACs you are comparing but let’s say early Delta Sigma implementations had a reputation for hashy highs or digital glare. Recent implementations like the Benchmark series of DACs sound very clean articulate and neutral. They do not suffer from lack of rhythm or bounce (quite dynamic and punchy) but they are thinner or leaner sounding (neutral is probably a good description) than a DAC with a slightly more euphonic output (tube or R2R).

As I mentioned on another thread - if you 100% love the sound of your speakers then a neutral DAC will work. If you don’t 100% like your speakers then some slight coloration in the source may be beneficial holistically.

@kclone  

R2R requires a ladder of very highly matched resistors as each 16 or 24 bit data point (at whatever the sample rate) is decoded to a discrete voltage from the ladder.

The advantage is no conversion of the digital data.

The disadvantage is that digital converters are mathematically extremely accurate and can achieve better performance if done properly with proper dithering to eliminate quantization error.

It is like DSP done with analog filters versus doing the filtering in the digital domain. Cheaper and greater accuracy can be achieved in the digital domain.

The problem of R2R is maintaining accuracy of a super accurate R2R ladder as resistors will drift with temperature and the tolerances required are extremely tight to achieve desired performance. Generally you get more THD and noise with R2R vs modern Delta Digma.

That said - a lot of Delta Sigma chips were used incorrectly by many manufacturers that did not understand how to implement conversion accurately - so many Delta Sigma chips - especially the early Sony ones did not sound good and had what people called "digital glare".