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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
mihorn
908 posts
 

OP  $3000 and lower DAC’s sound almost identical

$3k? To almost people, 260k DAC sounds a lot better than #3k DAC. But to my ears, $260k DAC sounds same veiled and bright as cheap DACs. They are small differences behind thick veils anyway. Simply, they all are unlistenable to me. The source is as important as speakers. Alex/Wavetouch audio

mahler123
4,001 posts
 

I dispute the premise.  I have heard significant variability in sound in sub $3K DACs even amongst ones using the same chip

shadorne's avatar
shadorne OP
7,491 posts
 

 

Isn’t eliminating the “pre echo” exactly what Meridian’s apodising filters (circa 2008) were designed to eliminate? Not mitigate, eliminate - at the expense of higher artifacts on the post side. I also thought that has been largely replicated now as “minimum phase” filters in other DACs.

The Meridian apodising DACs do sound quite good to me, but then so does its old 566 - Delta Sigma chips, and way before the apodising filters. 

I’ve heard the sterile, etchy nature you cite in other DACs, and certainly, I do not like it at all! 
 

@mulveling 

Excellent point - especially about sterile etchy sound - and yes an MQA style apodizing filter might improve things but it is what I would call a Band-Aid and this is why:

The ringing you refer to above is in the time domain. It happens at the cut off frequency. It only occurs on signals that exceed the Nyquist frequency. Properly produced music should not have transients above 21 KHz. It’s actually a non issue and unnecessary. 

However, an apodizing filter will change the sound and energy distribution - so it will sound less accurate but may be arbitrarily preferred by the listener - especially on poorly produced material that has many non-musical transients at 22.05 KHz (which will ring).

 

$3000 is arbitrary to be the cost at which ladder-R2R and discrete DACs become available. Obviously older DACs with TDA 1461 may be found used for less than that but I am generalizing with respect to current DACs being manufactured.

shadorne's avatar
shadorne OP
7,491 posts
 

@mahler123 

Indeed there are differences due to the upsampling filters used and other designer tweaks - that said there is usually no way around the upsampling function built into these Delta Sigma chip DACs where EVERYTHING ultimately ends up converted to high rate DSD in the final stage. However, the difference between these Delta-Sigma upsampling chip DACs and a modern R2R ladder DAC or PC upsampled audio to DSD256 to a discrete DSD DAC (no chip) is in my experience much more dramatic.

 

erik_squires
17,543 posts
 

I've heard all sorts of DACs except R2R. Personally I dont' think the issue is delta sigma so much as the current to voltage converters.

DACs have universally gotten much better at playing Redbook in the 21st century than almost anything that went before them, to the point where upsampling and similar technologies barely make a difference when older DAC s really demanded high rez material to sound their best.

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