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Why most $3000 and lower DAC’s sound almost identical

I have a theory as to why all modern DACs essentially sound so similar these days, making it difficult to differentiate between them. IMO modern Delta Sigma chips have homogenized DACs into close to the same sound, making it very easy to take any DAC under $3000 and find it will sound good as another.

What I have discovered is that ladder R2R DACs and fully discrete DSD DAC’s are creating a better soundstage and less digital “glare”. An observation supported by countless others - nothing new. Anything with a Delta Sigma chip-based DAC that does oversampling will have less soundstage and more glare.

Nothing new so far - most of you will likely agree that that the above is a common consensus but here is the new bit, so read on if you are curious…

The dissatisfaction with this sound has led to a band-aid solution where Delta Sigma DAC manufacturers now offer a plethora of filters from sharp to smooth, linear phase to minimum phase. All of this is hand waving nonsense that offers a band aid to what is an absolutely fundamental design issue.

FUNDAMENTAL DESIGN ISSUE:

All oversampling with Delta Sigma offers superb measured spec at very low cost - it’s the logical choice for anyone using Precision test equipment to design a DAC. Typical chip filters use about 60 taps in their filters. They also ALL use Parks-McLellan filter designs (which has best “spec” and the short tap length is required for low-latency and easy processing). The result is a filter that has equiripple through the entire pass band. Mathematically it is a fact that an equiripple in the frequency domain equates to two echoes in the time domain - a pre-echo and post-echo. The “digital glare” heard is because of these echoes, likely the pre-echo is most audible. Our ears brain are processing the echos because unlike noise they are a complete reflection of the entire audio signal - low in level but lasting long enough to be detected by our acuity to locate the source of a sound. It is the same reason our speakers sound and image much better when moved out into the room and away from any close proximity to reflective surfaces. Despite these echoes being 60 db down from the primary signal, my listening sessions have convinced me of their audibility, particularly the echoes caused by the first 2x upsampling for 44.1 Redbook data (less so for higher resolution files).

CONCLUSION

Those who are trying MQA and various filters with typical Delta Sigma DAC’s are using band aids. A growing number of critical listeners have discovered that ladder R2R sounds better than typical DS DACs or, alternatively, that high precision conversion to DSD256 on a computer fed to a true one-bit discrete Delta Sigma converter (no chip) sounds equally great too. 
 

Basically any conversion that eliminates oversampling/upsampling done on a chip is going to have less digital glare and better soundstage because of this absolutely fundamental design flaw in ALL Delta Sigma DAC chips.


 

shadorne
shadorne's avatar
shadorne OP
7,487 posts
 

@dsnyder0cnn 

 

Unfortunately, the ESS chips all have pass-band equiripple just like other DS upsampling chips. This results in echoes (exact copy of entire audio at lower level just like a reflection)

Ringing is not the same as echo.

Ringing is a Gibbs phenomenon and mathematically it occurs at the corner frequency of the filter - unless you can hear 21KHz (typical corner) then pre or post ringing will be inaudible anyway. In truth it should not be on any digital audio mastered file/CD because those frequencies above 20 KHz should have been filtered out prior to A to D.

The problem with any filter other than a sharp linear phase at 21KHz is that 

1) It changes the phase of high frequencies compared to low frequencies which changes the timbre.

2) any smooth filter with slow roll off can be leaky and frequencies above nyquist can get through, resulting in intermodulation distortion.

This is just from a technical perspective. Of course what sounds better to the listener trumps everything else.

 

mcraghead
5 posts
 

I went from a $300 Geshelli Labs J2 to a $1300 Denafrips Ares 15th. The sound was completely different. 

@halfastro Is that Ares better than the J2 or just "different"?
webking185's avatar
webking185
224 posts
 

My goodness. A $1k DAC super duper awesome. The Schiit Modi 3 for $100 does good for me compared to my Gustard X26pro.  $3K must have something special.

shadorne's avatar
shadorne OP
7,487 posts
 

@cundare2 

 

T+A, one of Europe’s ’s most highly regarded manufacturers of high-end DACs (well-known on the continent and now starting to establish a rep in the US) sells sophisticated $5-9000 dual-path DACs that process PCM with Delta-Sigma circuitry, but run DSD through an independent bespoke R2R DAC. 

T+A D200 DAC is incredible. I was wildly lucky to get one. It does have separate PCM (using a Burr Brown chip) and a discrete DS DAC that accepts DSD up to 1024. The DSD side of the DAC runs without upsampling and is the best aspect of this DAC, although PCM sounds pretty good. 
 

Another, similarly priced DAC is the Holo May KTE - this one supports DSD and NOS via an R2R DAC. It is equally highly regarded as the T+A D200. 
 

Both overcome the upsampling limitations of the short tap filters of a typical chip-based DS DAC.

As mentioned, elsewhere in this thread, not all filters in DAC chips are optimized by Parks-Mcllelan - yet this approach yields the best specs - so it’s been almost a standard approach for years. However even those filters without this design will suffer from equiripple. Even “smooth” filters have equiripple. Only NOS R2R or 1 million+ taps upsampling  (like Chord Dave) or super high precision conversion of PCM to high rate DSD on a computer (also using high number of taps) can sufficiently reduce pass-band equiripple and the echoes it generates. Only R2R can do so and not introduce latency.

 

 

cundare2
292 posts
 

I’ll have to check out that Holo DAC.  Sounds interesting.  Any technical papers you’re aware of that detail what’s under the hood?

One thing that continues to amaze me is the lack of T+A awareness among street-level audiophiles.  See, e.g., this thread itself.  One reason might be T+A’s low profile at American shows.  I was speaking to a colleague who visited two AXPONA booths that featured T+A gear last month, and he reported that neither setup produced SQ anywhere near what I hear at home from my T+A integrated, which is the sole source driving a pair of Harbeths through mid-fi (like $1K) cables.

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