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The Border Patrol DAC - Maybe linearity in a DAC is bad ... Spitballing

Hi Everyone,
I've been thinking about a few things related to DAC's and how they behave and how we hear. Also thinking about a couple of audiophile comparisons I've heard and how we interpret what we hear.

Let's talk about this simple measurement called linearity.

In a DAC what we mean is that as the magnitude changes the output changes the same amount. That is, if the signal says "3 dB softer" you want to get exactly 3 dB softer output on the jacks.

And with modern, top tier DACs this is usually really good until around -90 dB where noise becomes the limiting factor.

For a long time I felt that a DAC which allowed me to hear the decay of a note, so that it fades instead of stops suddenly was the mark of a truly excellent sounding DAC.

I'm wondering if what I'm actually hearing is compression? Lack of linearity.

The reason I bring this up is that I was reading a long article about the complexities of reviewing a DAC from Border Patrol. One of the main failings, from measurements, is that it is really not linear at all. Sounds don't get softer fast enough. And ... low and behold, Herb Reichert actually makes many comments about how much more he can hear with this DAC than with others.

I'm going to link to a critique of the "scandal" so you all can get a better look:


https://parttimeaudiophile.com/2019/01/06/border-patrol-dac-revisited-audio-fur/


Also, take a look at the linearity charts in the original review. Honestly, awful. Not up to what we expect in state of the art DACs today, but ....


https://www.stereophile.com/content/borderpatrol-digital-analogue-converter-se-measurements

What do you all think? Do we need a compression feature in DACs so we can hear more details? That would make more sense to me than a lot of the current fad in having multiple filter types.

Best,
E

erik_squires
erik_squires OP
16,056 posts
 
Apparently I like the decay and transparency of a typical DAC because I felt the Border Patrol sucked the life right out of my system.

If I interpret this as a loss of dynamics, it would be too much compression.

It’s not that it’s literally removed, but rather that the resolution of one is superior, allowing to hear deeper and wider into the soundstage, thus capturing the extremely minute character of the reflections off the walls of the venue. 


Which would be easier to hear with compression, not expansion.


erik_squires OP
16,056 posts
 
Anyway, I don't know anythiung for sure, I'm just spit balling about compresion, and air and dynamics.

I used to think more air = more linear. I'm not sure now. :)

emcdade
95 posts
 
One album I remember distinctly with the Border Patrol was the Daft Punk RAM album.  It has several tracks with beautifully recorded drums and cymbals.

The cymbals with the BP Dac sounded dark and with very little decay, no sparkle and air.  This is not the cymbal sound I know from a live drum kit.  “Live” sounds wide open with plenty of HF energy and of course natural decay with a cymbal.  

Other DACs I’ve had in my system give goosebump moments on this album but it was a strange experience with the BP.
onhwy61's avatar
onhwy61
5,218 posts
 
In the Stereophile 2nd opinion review the reviewer specifically mentions that the Border Patrol sounds like the Benchmark, but with a vintage tube compressor inserted.  It's not surprising that listeners would like the resulting sound.  It's a fleshed out, pleasurable sound.  Over the past years I've used two different devices to introduce slight amounts of compression into my primary playback system.  One was all analog, the SPL Tube Vitalizer and the other was digital, a Drawmer 2476.  Both worked well, but ultimately I stopped using them.  When taken out of the system I realized how they "homogenized" the sound.  I was a likable effect, but it was an effect.
There's no right or wrong with the Border Patrol vs. Benchmark.  I just wish people would approach it rationally with some understanding of the engineering involved.  Tube compression sounds really nice and recording engineers have known that since the 1950s.
erik_squires OP
16,056 posts
 
In the Stereophile 2nd opinion review the reviewer specifically mentions that the Border Patrol sounds like the Benchmark, but with a vintage tube compressor inserted.

Good find, I missed it.

Also, given the difference in non-linearity and difference in listening experiences, I wonder if a major problem is manufacturing consistency in the R2R DAC?

Best,
E



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