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| JanVigne |
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I'm rather unfamiliar with computer based audio systems. For all their pros of storage and access convenience they still seem to have just as many cons given all I have read on the subject. And at the moment I have no intentions of moving a computer into my main listening room. I would, however, be interested in experimenting with portable digital players feeding a DAC which would run to my system. In other words, I'd prefer to dispense with the spinning hard drive and go straight to a storage device such as a flash drive or a SD card.
The first question I can't seem to find an answer to is, how much voltage does a USB DAC draw from its source? I can't seem to find an input voltage requirement on any USB DAC nor can I locate the output voltage of either an "average" computer's USB port or from the "average" portable device. I'm guessing the portable would power the USB port for at least a period of time which would allow an average listening session for me - a few albums - before running out of sufficient battery power. But is the battery power from a portable device alone of sufficiently high enough voltage to work with a USB DAC?
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| dmitchell |
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Nick would be the guy to answer this one.
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| Hawkbilly |
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I thought it was 5V DC. Not 100% sure though. I don't think I get exactly what you are thinking Jan, but it sounds like you'd like the playback device to power the DAC via the USB connection ? What were you thinking of using for a source ?
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| N1ck |
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I dont know how I missed this thread. Dave it appears that I get emails when people reply to threads but not when they create new threads? Perhaps this is normal which is fine, I just need to check in more often. Sorry been busy.
Jan USB 2.0 outputs 5Volts DC and allows for a draw usually of 1.5amps of current and USB 3.0 can handle a maximum of 5amp of draw from the source being powered by it, also at 5Volts DC. That said small DAC's like the HRT music streamers simply power themselves from USB but larger DAC's integrating input switching and dedicated power supplies obviously will not.
Your idea of going solid state source for the music is a good idea. Fans, 3.5 and 2.5 inch hard drives and such do create noise in the signal. Measurable yes, but audible? that can stay with the cable arguments. More importantly for sound is driver integration, codec integration and the player your choose. If you do not have the know-how to make your PC solid state the closest and cheapest solution to get there would be a laptop. 2.5 inch Laptop hard drives, while still presenting moving parts, typically spin at lower RPM's then the latest 3.5 PC drives and do produce less noise. Small fans are noisy, but you can tweak the power options in Windows to have all cooling off as well as components within the system go to sleep once the system is in idle long enough, or in this case you have q'd up a music session and let it play.
The problem I see with using a handheld Device fed into a DAC is that both DAC and Handheld Device will both be looking for a USB-A port to power them both, typically. Which would not work. Unless I am mistaken on what you mean Jan.
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| dmitchell |
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Nick, people only get emails from threads to which they have contributed.
On the main forums page there is a list of newest threads, sorted by newest.
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| N1ck |
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That makes sense Dave. Thx bud.
On another issue I see simply using a Handheld with a USB Dac would be driver integration.
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| JanVigne |
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Things that require more 'Splanation, please ..
"Jan USB 2.0 outputs 5Volts DC and allows for a draw usually of 1.5amps of current and USB 3.0 can handle a maximum of 5amp of draw from the source being powered by it, also at 5Volts DC. That said small DAC's like the HRT music streamers simply power themselves from USB but larger DAC's integrating input switching and dedicated power supplies obviously will not."
Yes, I can opt for a DAC with its own power supply, either on board or built in. That would eliminate the requirement for the source player to power the DAC. But my curiosity is centered on the DAC's which would not involve any connection to the AC outlet and which would therefore not require any subsequent rectification from AC to DC in a conventional power supply. "Black" backgrounds typically begin in the power supply and minimizing or eliminating any AC ripple noises which could enter there. My battery powered T amp excels at "black". Just as I would hope to eliminate moving parts and other disruptions to the music generated by a computer of any sort, I would like to explore a system where batteries provide the power for the source player and the DAC. IMO that sort of playback system should provide what you might consider to be the "cleanest" source.
"More importantly for sound is driver integration, codec integration and the player your choose. If you do not have the know-how to make your PC solid state ... "
"Solid state"? Nick?! I finally arrived at a solid state computer awhile back though that old tube version is still taking up and heating an entire room and really can't do much more than simple addition. I did get it cheap though at the Army/Navy store's garage sale clearance. LOL!
I don't understand what "solid state" refers to here, Nick. To me "solid state" is nothing more than a reference to any product not using vacuum tubes, but instead relying on transistors or FETs, to provide its operation.
"The problem I see with using a handheld Device fed into a DAC is that both DAC and Handheld Device will both be looking for a USB-A port to power them both, typically. Which would not work. Unless I am mistaken on what you mean Jan."
Here's one article that sparked my interest in this configuration though I have no intention of running an iPod Shuffle as the power source for a USB powered DAC; http://www.positive-feedback.com/Issue59/ipod.htm
My intent was to use my digital recorder which we discussed in a previous thread. http://www.zoom.co.jp/english/products/h2/
It uses high capacity SD cards for a storage device, can upsample when run through a DAW first or record directly from another digital source at higher bit rates but, at the least, records in CD quality WAV without problem (and with substantial recording space available at that bit rate) and has a USB output. It runs off either two AA batteries or an external wall wart type power supply, so Voltage component out from the USB can't be anything more than slightly under 3VDC - amperage would depend on the batteries used or the external ps.
My interest was recently increased by this DAC; http://www.techradar.com/reviews/audio-visual/hi-fi-and-audio/hi-fi-accessories/jolida-glass-fx-mini-dac-674040/review
A dealer was showing a Jolida/Linn system at the audio show here in Dallas a few weeks ago and using this $120 DAC from his computer output. I didn't get into any long discussion with him about the DAC but got to thinking about its versatility if it could be powered by the Zoom recorder. The system comprised a Dell laptop into the DAC then to a Jolida integrated tube amp which powered the Linn Akkurate 242's; http://www.linn.co.uk/systems/products/loudspeakers/akurate-242 Not the most detailed system at the show - that honor went to a system with about 50 times the monetary investment - it was rather ear catching for its simple muscality and its high degree of cleanliness in all the right ways. Musical lines certainly stood out from a very quiet background despite the tube amp in the signal path.
Now, to put this system together I could use a DAC with a conventional power supply. But, if the USB DAC could be driven from the battery powered portable, that's an experiment I would prefer to begin with just for S&G's.
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| JanVigne |
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Here's another little USB powered DAC that states a 5VDC power requirement; http://www.nuforce.com/hp/products/iconudac2/
Looks like my plan isn't workable.
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| N1ck |
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""Solid state"? Nick?! I finally arrived at a solid state computer awhile back though that old tube version is still taking up and heating an entire room and really can't do much more than simple addition. I did get it cheap though at the Army/Navy store's garage sale clearance. LOL!"
LOL!! Solid State to computer geeks is a term used based on the latest Solid State hard drives which are flash based media instead of a platter. What I mean by the term "Solid State PC" is a PC built with no moving parts at all. No Fans to cool it, but heat sinks instead. Solid State hard drive with no moving parts, fan-less Power Supply and integrated CPU or CPU cooling done by heat sink as well. No moving parts in the system what so ever, which is really the only disadvantage I can see in computer audio, is too much noise created by movement. A Solid State PC (absolutely 0 moving parts) is IMO Audio bliss. LOL! You make the Audiophile's want to use PC audio, and you make PC guys want to become an Audiophile. orrr ahh sort of. haha
I think you idea is a cool one, and I am not sure why someone hasn't came up with a device, like yours that could present a solution to what you want to accomplish. The reason I do not see it working is this : There are two types of USB connectivity happening in a USB connection. There is the USB-A and USB-B connections. A is generally the port providing the power to the device. The Device (your handheld is this case) is using the B style connection to communicate, and retrieve the power from connection A. The problem with your situation is that both a USB powered DAC and your Handheld device both probably have B style connections (your handheld probably a mini-b) in which both will be looking for power, but neither one able to power each other. Even with your handheld powered by batteries I still do not see how this works. But hey, I have been wrong on many counts.
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| N1ck |
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To add, both the Jolida DAC and the NuForce Dac look very cool. Jolida IMO has always had great sounding stuff especially in its price categories.
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| JanVigne |
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OK, so the original idea doesn't appear to be functional at this time. Someone will develop a product along those lines and they'll make their fortune on it.
Let's switch to iPod docks. Lots of stuff out there for iPods and MP3 players which allow their use in an audio system. What's the dock doing? If I went with a DAC which draws its power from a conventional AC rectified power supply, is there a need for a dock ? Or, is this just dressing things up to sell a product that isn't really needed when I look at the price of these docks? Can a portable, battery driven device be plugged straight into such a DAC without the intervention of a dock?
Also, Nick, can you easily explain the difference between synchronous and asynchronous USB's?
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| N1ck |
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There is some in depth differences between sync and async usb. To sum it up to someone who wants to use it in a dac..Sync is the typical USB we have learned to hate in the every day DAC. Its a two way communication where the USB connection needs a device to accept the communication (ie. Power, Driver) and is dependent on such. Async USB is USB connection integrated with its own dedicated Power supply or shared off the likes of the internal PSU on the DAC as well as having its own internal clocking. This means that most Async USB connections do the clocking in the DAC itself instead of having the dreaded PC do the clocking which is why USB is generally terrible sounding. If you were to buy a DAC that had its own AC connection with Async USB then you should technically be able to plug in your Handheld into the Async USB connection and produce tunes. Although I have never tried this myself. This may be your solution right there Jan. Of course Async USB will always be found on a DAC with its own PSU I would assume. But!! If your going that route now, this may very well work out. I believe WaveLength DACs were one of the very first to start using the Async USB technology. Heres the kicker that most Audiophiles will squirm at...Async USB is actually cheaper to integrate. haha. For DAC integration it is a far better connection.
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| N1ck |
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IPOD Doc's act as a proprietary connection to an IPOD (everything Apple is proprietary *puke*) in then usually uses a cheap pathetic internal DAC with RCA out. Some Hi Fi companies have integrated IPOD connection into somewhat "high end" dac solutions. IMO I would start looking for Powered DAC's with Async USB as its far more flexible. If your looking for a cheap solution for testing the waters I always seem to come across FireStone USB dac's with Async USB for under 200. Not sure if they sound good or not, but some have compared them to the Dac Magic by Cambridge Audio and preferred the FireStone by a good margin. Just a thought though.
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| N1ck |
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I guess we need to find someone who has connected Async USB up to something other than a PC. lol. I will dig further.
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| JanVigne |
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"Heres the kicker that most Audiophiles will squirm at...Async USB is actually cheaper to integrate. haha. For DAC integration it is a far better connection."
That's interesting considering this pricing schedule; http://www.nuforce.com/hp/products/iconudac2/index.php
NuForce, in their extremely, incredibly, not really saying anything at all short mention of asychronous vs synchornous USB mentions the more tedious set up for the asynchornous version. Any idea why the set up is complicated? Or, even different? I would have assumed the DAC would have taken into account which device was doing the clocking and made its own adjustments.
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| N1ck |
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Jan what NuForce states as a difficult installation makes absolutely no sense to me. lol Every other company integrating Async USB states the complete opposite where its an easy plug and play installation that simply uses the built in Windows or Mac USB support. That said though I wonder if it still needs A driver to communicate. Weather built in or not, it may still have to be there. This is crucial that we find this out as this would be a make or break. I will find this out.
I was just scouting the Wavelength DAC's as they are on my short list to try and came across a really good explanation of why Async is superior as it cuts out the PC doing the clocking. Just scroll down a bit.
http://www.usbdacs.com/Concept/Concept.html
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| N1ck |
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Going back to pricing, I believe its what is needed in the DAC to use the Async USB technology that may make it more money. That, or they know what people want more they will pay more for. lol. As far as USB alone goes, Async is cheaper, and typically easier to integrate into basic PC audio cards.
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| Hawkbilly |
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http://www.hifi-advice.com/USB-synchronous-asynchronous-info.html
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| dmitchell |
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I just got re-interested recently in computer playback as a source in my system.
Since the source I'm using (a 6 year old laptop) does not have an optical or coax out for sound, I am stuck with using USB. I've always sort of viewed USB as inferior to using a coax link, but I guess technology has come along a bit. Helps too that my DAC (in this case, the Audiolab) has an async USB input.
I'm actually quite surprised how good it sounds. CD playback may be just a bit better (or maybe I'm just used to that more), but it is negligible. One thing I do notice, though, is every now and then the timing in the music seems to just a bit off. Network latency maybe? I am streaming the files from a central file server in my house with a 2TB drive, but both machines are connected via ethernet to a switch in my basement.
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| N1ck |
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Hey Dave is your old server Gigabit along with the rest of your network? Music streaming wasn't great on my network and movies was impossible, found out my dirty old Xbox was killing my streaming capability.
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