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Computer Audiophile


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  1. The link you provided (to thread on Steve Hoffman forum) is just about curing ground loop hum. Nothing new there at all, and most folks here at CA are already well past that point. Breaking leakage loops, improving clocking and signal integrity, and things with power supplies and interfaces to obtain better sound is going way beyond eliminating system hum and noise.
  2. Article: Computer Audiophile Turns 10 Today!

    I try not to. Actually, my hearing is still good, it's my tinnitus that has gotten worse.
  3. It is a bit of a chicken/egg or Catch-22 situation. Computer operating systems don't directly support audio through many interfaces beyond USB (and heck, Windows is only just this year adding UAC2 audio support--for USB devices at hi-res). Any hardware manufacturer that would want to introduce a new and more audio-ideal interface will both have to develop and support OS drivers for it and recruit DAC manufacturers to adopt it. It could--and may--be done, but it will take time. As an example, just look at Ravenna/AES67 for Ethernet audio: It has been promised to "take over" for years--and still has yet to make the slightest dent. Not that it won't. But it illustrates my point. And Merging's VSC (virtual sound card) software will be the key. Still, it is not a certainty that Ethernet>I2S will actually be the most ideal or immune interface. Again, we'll have to wait and see. So there you have my short answer as to why computer audio is "stuck" with USB.
  4. Sorry, but this is a gross oversimplification of much more complex issues. Still, welcome to CA. Hope you stay and keep reading.
  5. Article: Computer Audiophile Turns 10 Today!

    Funny, I still have your very first business card Chris--from our first meeting in the Hovland Company suite at CES Las Vegas, January 2008. We were showing the prototype of an ahead-of-its-time/ahead of the tech CD data player/DAC/music server, with Ethernet input and credit-card-size Linux module. It never made it into production, but you sure enjoyed asking questions about it. John Swenson did not attend with us that year but the digital parts of the piece were all him. Flash forward many years and I could not be happier to have found community here at CA. Yes this place and its populace have been very good for our business, but for much longer I've enjoyed just being another enthusiastic audiophool exchanging ideas, tweaks, and music with everyone. So I raise a mouse to the next decade of The Computer Audiophile! Who knows what this fascinating and musically rewarding hobby will look like in another 10 years. --Alex C.
  6. SMPS and grounding

    a) It's not high frequency noise, it is is high-impedance common-mode leakage (which has both high and low freq. components); b) You are correct that grounding the output of a linear supply is not needed--except with regards to the specific Netgear switches that John tested, for which grounding whatever power supply is used allows that Ethernet switch to shunt leakage currents coming in on the CAT cable from other upstream gear. So it is not so much that you are grounding the PS for this switch, just that it is the easiest place to ground those unique switches (and which if you are using an SMPS for it--just fine--will also take care of ITS high-impedance leakage).
  7. SMPS and grounding

    No, it can not be both ways. Either all the rails share a common ground, or they are all floated from mains ground.
  8. SMPS and grounding

    The UltraCap LPS-1 does not tolerate "energizing"/charging input above 12V. Even a short spike above 12V can fry one of its input regulators--turning the board into scrap. Four of the six destroyed LPS-1 boards we have in a box here came from people using an HDPlex power supply. Now I do not know the vintage of the offending HDPlex units owned by those who have suffered, and while HDPlex seems to offer good value (and I know they offer good support), at this time we must advise against using that brand as a charger for our LPS-1. Perhaps one set at 9V would be safe, but that is no guarantee. It is easy for us to inspect a failed LPS-1 board to determine if an over-voltage killed it: Such is not covered by our warranty. As this thread--and the graphs that we published made clear--there is no advantage to powering an LPS-1 with a linear power supply versus the Mean Well we include, once the Mean Well's output is shunted. I am still trying to make arrangements with a quality SMPS manufacturer to supply us with units that already have their zero-volt output ("ground") tied to the AC mains ground pin. There are some that do so already, but we have multiple factors to consider in making our choice before I make the required 1,000 unit stock purchase. Thank you all for your enthusiasm, patience, and understanding. --Alex C.
  9. CLOCKS, what should we look for in next generation

    That's a very good article Jonathan, thanks! (What makes it "good" is that I actually understood most of it. )
  10. Hi: Here is something that John Swenson wrote a while ago that is likely most relevant. Hope it helps: So I have been trying all kinds of things today and the issue is generic, the microRendu will NOT see a hotplugged hub, period. Any hub attached has to be plugged in and powered up at boot time to be seen. As long as the hub stays connected (USB cable plugged in) and power applied, plugging and unplugging, or powering on and off DACs seems to work. The kernel will happily hotplug devices on the other side of a hub, it just won't hotplug the hub itself. There MAY be an issue with some DACs that power the receiver from the bus, but the rest of the DAC is self powered. If the receiver stays powered up and connected and the rest of the DAC powers down and comes back up the rest of the DAC and the receiver may be out of sync. None of my DACs show this behavior but it MAY happen. Any USB receiver chip should be implementing the "connect protocol" properly so a hot plug should work. So it doesn't look like a REGEN specific issue.

    This might make your head explode, but the fact is, all digital isolators (call them "galvanic" isolators if you wish) add jitter--sometimes a lot (though smart designers reclock most of it out with a flip-flop or other process afterwards). Free lunch will not be served...
  12. SMPS and grounding

    I love you guys...
  13. SMPS and grounding

    Sorry Cornan, but while I appreciate your enthusiasm and the pleasure you get in doing tweaky things, I am going to call BULL on the notion that silver wires improve the ground-shunt of an SMPS. That is just a bridge too far. John's trick of shunting an SMPS' high-impedance leakage to ground makes a measurable difference--and for some an audible one. But using a silver wire to do it is not going to do anything. You can do these things (though replacing the 3+ Gopher SMPS units in your system would give real benefits) but I feel the need to say something here as I really don't want John's based-on-engineering mod to get too mixed up in hoofy-spoofy stuff. We have enough of a time already with skeptics calling our actual products "snake oil." All good wishes to you, --Alex C.

    It's a trick question...
  15. In this case it's his cable up his [braided] sleeping.