Schiit Happened: The Story of the World's Most Improbable Start-Up
Apr 24, 2014 at 4:53 PM Post #931 of 144,027
But more seriously, have a look at Rocky Mountain Audio Fest videos of presentations by people like Keith Johnson, and think about how he takes a much more (literally) "outside the box" view of common problems with audio systems, focusing on system-wide interactions.  Or consider the age-old argument about whether power cords matter.  You can look at the power cord alone and be stuck in the same old back-and-forth: "But I hear a difference!"  "But you can't from 3 feet of wire!"  Or you can look at it from a system perspective and with a couple of bucks worth of parts you can make your transformer much less subject to "ringing" behavior and thus tremendously reduce or eliminate any sonic difference from power cords.  (Google "snubber circuit," "Hagerman," and "John Swenson.")

Ok, I get where you're coming from now with the comment. I was having trouble understanding the context. I totally agree that a whole-system approach to design will always give better results. As a chemical engineer, I've seen a lot of systems fall apart because one part of the system was designed separately and does not "talk" to the rest of the system. PID loops are single in-single out as well, so that causes a lot of horrible problems since people are too cheap to implement more elaborate control schemes.
 
Apr 24, 2014 at 8:03 PM Post #932 of 144,027
   
There is a reason why I am so pumped for the Yggy, way more than I am for the Ragnarok, and it's cause of the fact that its going to be a ladder dac and this filter...cant wait to see it! Im thinking it's going to be as advanced as some of the best computer based digital filtering out there, but without needing all the computer horsepower.
 
Now we just need to know if it will have i2s, via either hdmi preferably or rj45 if not...

 
+1
 
The trick is laser trimming those resistors for matching just so... 
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   And in combo with FPGA filtering with the newer technology chips now available...  Please just let me be still able to say Schiit and affordable in the same breath.
 
EDIT:  Just read elsewhere that the 18K+ timing interpolation filter taps going to be via a DSP processor (+ the 1917 paper algorithm) and not FPGA, like some other recent products (e.g. Chord Hugo).
 
So you're blown away by the input HDMI I2S convertor board as well?  I still can't break away from the AD chip board long enough to try out the rave TI chip one.
 
EDIT:  Checked my source, and evidently you're not one of the DIY board recipients.  No soup for you! 
wink.gif
  Apologies.
 
Apr 24, 2014 at 8:55 PM Post #935 of 144,027
Ok, I get where you're coming from now with the comment. I was having trouble understanding the context.


Yeah, sorry about that. I was thinking about trying to explain that a bit more but decided the comment was already pretty long.
 
Apr 24, 2014 at 9:28 PM Post #936 of 144,027
I know this is a popular viewpoint, but the full flight manual (including performance charts) is declassified and available online. Top speed is limited by a compressor inlet temp of 427C, which falls somewhere around mach 3.0 to 3.5, depending on ambient conditions (primarily the air temperature at ~75-85k feet). Here's the manual - it can be very interesting to look through (and it was definitely an astonishing aircraft, and it would still be even if it were made today, much less in the 60s...)
 
http://www.sr-71.org/blackbird/manual/
 
Here's the speed chart: http://www.sr-71.org/blackbird/manual/5/5-9.php
Here's another chart showing max speed vs ambient temperature (based on the inlet temp capability): http://www.sr-71.org/blackbird/manual/5/5-10.php
 
Note that in extremely cold ambient conditions, it does show a capability for higher than mach 3.3, and it probably could push up as high as mach 3.5 or so if the external conditions were just right, but it isn't something it could do routinely without risking engine damage (the reason for the CIT limitation). In addition, if you do the shock angle analysis for what speed the SR-71 would be traveling when the nose shock starts to encounter the wingtips, you end up with a mach number of around 3.3 or so, which further supports that its true design top speed was in this neighborhood. That having been said, sustained cruise at mach 3.2 is nothing to sneeze at - it's still the fastest manned aircraft ever built that could take off under its own power, and the only other ones that ever got even close could not sustain that kind of speed for very long (as opposed to the SR-71, which could cruise at M3.2 for an entire tank of gas without difficulty).

 


Huh, you don't post often it would seem, but I really enjoyed reading this, thanks for posting it! even though it was mostly off topic.
 
Apr 25, 2014 at 1:22 AM Post #939 of 144,027
  Oh, and Yggy's digital filter? 18,000+ taps, running a proprietary algorithm based on a 1917 Western Electric paper on time-domain optimization (yes, nine-teen seven-teen, 1917), perfected by a Professor Emeritus of Mathematics at Iowa State (to get around the divide-by-zero problem) and implemented by a RAND Corp mathematician. 

How did you even find that paper? Where you actually looking in academia or did you just happen upon it? Sounds too convenient to be true haha.
 
Apr 25, 2014 at 1:54 AM Post #940 of 144,027
Huh, you don't post often it would seem, but I really enjoyed reading this, thanks for posting it! even though it was mostly off topic.

It's true that I mostly lurk (especially outside of the sound science forum, where I do emerge from time to time), but my degree is in aerospace engineering with a focus on high speed fluid dynamics, so if I see a post about something like the SR-71, I can hopefully contribute something interesting and/or useful
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Apr 25, 2014 at 2:48 AM Post #941 of 144,027
Ok so I gotta ask… :thumb
 
At the boundary layer?
 
JJ 
 
Apr 25, 2014 at 12:37 PM Post #942 of 144,027
O.K. The Schiit web site was down during the night, and it's 17:30 now in the UK and it's still down. What's happening? Not that I'm worried, of course...
    ___
"'«{°î°}»'"
    """""
 
Apr 25, 2014 at 12:43 PM Post #943 of 144,027
It's up and perfectly fine.
 

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