Audio-gd Digital Interface
Jul 4, 2010 at 4:02 AM Post #31 of 4,156
The upcoming M2tech Evo will have AES, BNC, RCA and IS2 - and a 10V DC input and timing lifted away from the computer with two built in clocks and even an input for an external clock unit.  It just ticks all the boxes.  Period.
 
Jul 4, 2010 at 8:10 AM Post #33 of 4,156
Fair enough about the cynicism with the "kill" comment, but he has canned (ha!) a couple of ideas where either he wasn't satisfied with the sound quality or reliability.  He is genuine about creating good gear (rather than flogging generic stuff on eBay), as well as genuine feedback as opposed to hype.
 
Wouldn't mind seeing some HiFace vs. USBFace jitter measurements though, after he's put in a 75 Ohm socket (someone, who shall remain nameless, suggested it was a 50 Ohm one, oops if so) and 75 Ohm wire.
 
Jul 4, 2010 at 8:29 AM Post #34 of 4,156


Quote:
Fair enough about the cynicism with the "kill" comment, but he has canned (ha!) a couple of ideas where either he wasn't satisfied with the sound quality or reliability.  He is genuine about creating good gear (rather than flogging generic stuff on eBay), as well as genuine feedback as opposed to hype.
 
Wouldn't mind seeing some HiFace vs. USBFace jitter measurements though, after he's put in a 75 Ohm socket (someone, who shall remain nameless, suggested it was a 50 Ohm one, oops if so) and 75 Ohm wire.


I'm very supportive if this is what he is doing and it does show his commitment to building a good product and I've seen from several posts that there is a fair bit of interaction between the manufacturer and the the consumers ensuring that the product is tailored as much as possible to the needs of the consumers and with good quality products in mind.
 
only comment is that I wish the design of the box itself could look a tad nicer
biggrin.gif
. yes yes, I know it makes no sonic differences heh.
 
Jul 4, 2010 at 10:02 AM Post #35 of 4,156

 
Quote:
Nice, I hope Kingwa will also implement this within his DACs, replacing the current USB input, so that we won't need an external box anymore.


That's what I proposed when the RE3 was first released. I'm not sure that having more elements (USb cable, converter, etc...)  in the sound chain can be very good for SQ.

 
Quote:
Wish it had AES.


You are your AES...
tongue_smile.gif

 
Quote:
Wouldn't mind seeing some HiFace vs. USBFace jitter measurements though, after he's put in a 75 Ohm socket (someone, who shall remain nameless, suggested it was a 50 Ohm one, oops if so) and 75 Ohm wire.


Kingwa has confirmed to me that the BNC socket on the USBface is 50 ohms because according to him the HiFace BNC socket is also 50ohms and he wanted to match the hiface as much as possible for comparaison purposes.

 
Quote:
only comment is that I wish the design of the box itself could look a tad nicer
biggrin.gif
. yes yes, I know it makes no sonic differences heh.

 
I'm ok with the design as long as the price stays low.
 
 
Jul 4, 2010 at 10:41 AM Post #38 of 4,156


Quote:
The Tenor chip is adaptive. Woot, the hiface is a 75 ohm BNC? Damn it, i need to replace the BNC on mine then


No it's a 50ohms BNC socket. Marco said that it the Hiface BNC would be true 75ohms but he's wrong.
 
Jul 4, 2010 at 6:50 PM Post #42 of 4,156


Quote:
75[size=medium]Ω female BNC connectors are hardly ever used for a very good reason, [/size][size=medium]and many ppl think that "the impedance mismatch problem at the connector is academical": http://recforums.prosoundweb.com/index.php/m/381397/0/#msg_381397[/size]
 
[size=medium]Does this interface use the Tenor chip BTW?[/size]

This could well be the pragmatic view of 75/50ohm connectors & the path taken by manufacturers but stating that impedance mismatch is academic is mistaken as far as I know. This 2008 quote from Bruno Putzeys (designer of Hypex amps) ignores the real speeds that cause the problems (reflections) of impedance mismatches & this is the rise time which is where the 0 or 1 are sensed. These rise times can be as fast as 2nS so reflections can be a real problem 
 
Jul 4, 2010 at 7:46 PM Post #43 of 4,156
A useful question would be: Will the socket make a significant audible impact? However, this would surely need measurements to determine properly IMO.
 
Jul 4, 2010 at 7:55 PM Post #44 of 4,156


Quote:
A useful question would be: Will the socket make a significant audible impact? However, this would surely need measurements to determine properly IMO.


If impedance mismatch happens anywhere (including the sockets) then theory says that it will cause reflections (at the speeds mentioned for rise times). These reflections can cause jitter - whether that happens in your implementation is down to individual implementations. But, is it not better to design out these issues in the first place rather than try to fix them at a later stage?
 
Jul 4, 2010 at 7:56 PM Post #45 of 4,156
This could well be the pragmatic view of 75/50ohm connectors & the path taken by manufacturers but stating that impedance mismatch is academic is mistaken as far as I know. This 2008 quote from Bruno Putzeys (designer of Hypex amps) ignores the real speeds that cause the problems (reflections) of impedance mismatches & this is the rise time which is where the 0 or 1 are sensed. These rise times can be as fast as 2nS so reflections can be a real problem 


Good point! But a short cable(1ft or so) should minimize those reflections? Dan Lavry thinks that the shorter your S/PDIF cable, the better
jyb34.gif

 
The thing is that I'm not sure any manufacturer wants to increase its RMA figures on purpose because they decided to go 75[size=large]Ω, but their customers ruined the connector due to 50[size=large]Ω[/size] cables..[/size]
 

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