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hojen

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  1. Frank: <br /> Keep in mind that I do my headphone listening exclusively in BALANCED mode, using XLR outputs. I have used my Seinheiser HD800's only briefly in Single-ended mode for the first month that I owned it. Since converting it to balanced mode, I have never looked back. The only way to drive my converted HD800, with the XLR plugs, is to use the XLR output of the DAC202, which was not meant to drive headphones. I don't necessarily disagree with the experience of others who say that it drives headphone well with its conventional single-ended headphone plug. However, you should check to see if those people drove high-impedance, demanding headphones such as the HD800.<br /> <br /> Prior to my current rig, I had<br /> the headroom BUDA/UDAC combo to drive my converted HD800's. I use custom made (DIY) silver foil interconnects and Headphone cables as per the Allen Wright (Vacuum State Electronics) design. Quite enjoyed this system, for ~2-3 years. Open, dynamic, accurate, musical.<br /> <br /> I then replaced the system with the Weiss DAC202, after reading Chris' review. True to his words, the DAC202 is simply outstanding as a DAC. More revealing, more subtle detail, especially for HD symphonic works; more clarity.<br /> <br /> I have now replaced the headroom UDAC with the Rudistor RP101B headphone amp. The theory of its design made sense to me: quad channel class A amp. In balanced mode, all four channels (+, inverted, R, L) are individually driven by their own power supply. The sound? Beautiful, definitely more life-like. Its raw power is obvious, but that's not where you appreciated the difference, compared to my headroom BUDA, which also had ample power. With the Rudistor, the overal auditory image is more lifelike, has more air, and is more "accurate". Loud, complex passages sounded more clear, accurate, remained better defined, and less fatiguing. Softer passages have more flesh on each individual performer, and more air between them.<br /> <br /> For me, the price difference between Rudistor RP101B/Weiss DAC202 vs headroom BUDA/UDAC is worth it, based on the performance difference, but that is an individual choice.
  2. The amp gurus out there are probably laughing at me for even trying this little experiment: driving a high impedance, power-hungry headphone with an output meant to feed a power amp probably makes no sense. I guess a more proper comparison would be to drive the HD800 via the conventional single-ended jack up front, with an HD800 headphone that has NOT yet been converted to balanced mode.<br /> <br /> I think I can predict the outcome of that experiment before I even try: you can't seriously expect the modest headphone circuit of the DAC202 to compete with the brute force monster power of a dedicated power amp like the Rudistor or any other good dedicated headphone power amp.
  3. Yeah. I did try out the power amp capability of the DAC202. My Sennheiser HD800 is modified to operate in balanced mode, with XLR connectors, so I had to wait get some XLR gender converters, to try driving them with the analog output of the DAC202. I played around with the nominal output voltages of the DAC202, pushing up to the highest value.<br /> <br /> Unfortunately, the DAC202, can't do much of a job at driving a power-hungry headphone like the HD800. Not at all surprised, though. This is NOT what you are paying for, with the DAC202. First and foremost, you are paying for a superb, state of the art DAC unit whose sonic performance as a DAC is well-documented. As a firewire based unit for a computer based audiophile system, it is unbeatable: a COMPUTER AUDIOPHILE's dream come true !<br /> <br /> I never intended to use my DAC202 as a primary headphone power amp, anyways. This trial was just for fun.<br /> <br /> The combo of DAC202 feeding the powerful and deadly accurate RudiStor RP101B quad mono power amp, driving the detail-rich Sennheiser HD800, is so far, the closest I have ever experience to actually "being there..", for a headphone system.<br /> <br />
  4. Yes, avoiding the DAC and external HD on the same set of cables makes intuitive sense. <br /> <br /> However, for all true COMPUTER audiophiles, I highly recommend a NAS unit on a gigabit ethernet, for convenience and robust, ultra-huge capacity music storage. This potentially noisy box does NOT even have to be in the same room as the rest of your audio equipment.<br /> <br /> Then, you don't have to worry about interference with traffic from PC to DAC.<br /> <br /> The total gear in my cramped little office (the NAS unit is in another room) is DEAD SILENT, except for the headphones !!<br /> <br />
  5. Yes, thanks for the correction. Upon review of the documentation for the Weiss DAC202, turns out that it uses a two-stage PLL circuitry, which corrects for both high and low frequency jitters, rather than controlling the source input rate per se. Might explain why I could consistently hear a difference between different brands of firewire cards, on different machines. I thought I was just plain crazy.<br /> <br /> But as Bob Stern points out, the DAC202 CAN be used as an external master clock, with good audio cards such as the lynx, which will accept an external clock input. Funny, then, how music through firewire sounded better than music through an externally synced lynx audio card via SPDIF, on the same setup, in Chris' thorough assessment of the DAC202. I haven't tried this yet, but you sure can't beat the super convenience of a single digital wire such as firewire, versus needing a PAIR of cables.<br /> <br /> BTW, Dennis, I don't think you needed firewire for the ext HD to Computer link. USB has a higher peak bandwidth than firewire, and the magnitude of data transfer from ext HD to computer is much higher than intrinsic audio data flow rates from computer to DAC. I have seen issues with temporary frame freezes when watching video from usb-external HD, but I doubt this would affect even HD audio.<br /> <br /> <br /> <br />
  6. "bit transparency" simply means the ability to send the digital audio data, exactly as it is stored on the media (CD, audiofile,etc), untouched by the OS, to the DAC. This is typically a matter of taking care of the details of how you are sending the digital music to the DAC. In Windows, it is a matter of ensuring that the output wav file does NOT get intercepted by the windows music mixer on its way to the DAC after leaving the software player, by using mechanisms such as asio, wasapi, etc. I'm not familiar with the JRiver software, but it is well-regarded, and I'm sure that it has the appropriate measures to ensure bit-transparency.<br /> <br /> Those familiar with JRiver please fill in???<br /> <br /> As for the USB transfer of data from hard drive to laptop, that is a non-issue. It should be instrinsicaly bit-perfect, like any other piece of data. Otherwise, you have a serious problem, if you cannot ensure error-free data transfer from external hard drive to computer !<br /> <br /> The audiophile preference for firewire vs USB is NOT a question of bit transparency. It is a matter of jitter control. Firewire allows uninterrupted data flow, as well as an intrinsic ability for an external device to control the rate of data flow, thus allowing superb jitter control. Whereas USB is NOT fundamentally designed for uninterrupted data flow. Better flow control is achieved only with 'asynchronous' mode usb data flow, which not all chipsets support.<br /> <br /> Hope that clarifies the issue.<br />
  7. Of course, I'm talking about music listening in the HEADFI domain! <br /> <br /> I don't want to insult all the owners of monster speaker units out there!<br /> <br /> Now, I'm in Headfi Heaven !!!
  8. I agree with your comment about the gigabit net. However, once you have a well-tuned gigabit net installed (using jumbo frames, for optimal speed), there's NO GOING BACK to 100 mbit !!!<br /> <br /> Enormous files in the 100 of megabyte size (such as HD audio) whiz back and forth between machines in seconds!. <br /> <br /> It's not even expensive to implement. Gigabit switches dropped considerable in price, all support jumbo frames. Most new mobos are gigabit compatible. Most drivers will allow you to use jumbo frame mode. <br /> <br /> What's holding you back?
  9. Just got my new legendary Rudi stor RP101B from Italy.<br /> <br /> Wow! headphone listening with this is probably the closest you can come to live music, as of the current state of technology:<br /> <br /> -modified silent CAPS PC server<br /> -NAS server on gigabit ethernet<br /> -Weiss DAC202<br /> -Rudi stor RP101B QuadMono Headphone amp<br /> -Senheiser HD800 headphone, in Balanced mode<br /> -custom balanced silver foil headphone cables and interconnects<br /> <br />
  10. My D510 motherboard-based silent PC is fast and sweet! No performance issues whatsoever! I don't think the current D510 chip was available at the time Chris did his work.<br /> <br /> Sure, I'll get my benchmarks for you later. Off hand, I would guess that it must have something to do with the dual core nature of the latest atom processor. I also used 4gig or ram (yes, I know that a 32-bit OS can't use all of this).<br /> <br />
  11. Thanks for the extensive review Chris, having done all the leg work. It was invaluable.<br /> <br /> Since your review, more atom processors have become available, and I think this is a blessing for us computer audiophiles, considering what it took a few years back, to build a silent, fanless system.<br /> <br /> I used all of your info, but opted for the newer Intel D510M0 motherboard with the newer dual core D510 processor. I opted for a cheaper but effective black case.<br /> <br /> My audio system is based on the Weiss DAC202, so I didn't need to get the Lynx audio card: just a good PCI firewire card.<br /> <br /> 160 gig SSD HD, 4 gig RAM.<br /> <br /> Win7 pro 32bit.<br /> <br /> Getting such a machine built was a breeze: there are web stores which specialize in mini-ITX machines, who have access to all the specialized components, and can build any such machine to your specification, for not much more than the component costs and shipping.<br /> <br /> The one chore most people must attend to is the need to "strip down" the machine and default OS components, to minimize the DPCs (delayed procedure calls) which I found to be moderate to long, in the default OS settings. This degrades the quality of the audio, and produces audible "clicks", whenever a particularly long DPC interval occurs.<br /> <br /> You have to carefully remove all the unnecessary features (disable audio, serial port, parallel ports, etc in BIOS and in the OS. I also removed various background services carefully. You have to update all the drivers to the latest versions. Slowly, I was able to bring down the average DPC interval to a very low value (<200 usec). <br /> <br /> I access my music library from a NAS unit on a gigabit network. To my delight, I found that the network access does not produce any significant increase in DPC intervals.<br /> <br /> So now, I have a smoothly running DEAD SILENT mini PC, accessing HD music on a gigbit network, feeding the Weiss DAC202 via firewire. This drives a headphone amp(Headroom BUDA), output to Senheiser HD800 headphones. All in the confines of a little cluttered office.<br /> <br /> This, for now, is bliss .<br /> <br /> This bliss will become audiophile heaven, when my RudiStor RP010-B MkII headphone amp arrives from Italy !<br /> <br /> <br /> <br />
  12. Yes, thank you. Guess it's well known or well believed amongst the professional users of firewire audio interfaces that Texas Instrument-based firewire chipsets are preferred. I will certainly follow up on that lead.
  13. Wouldn't that negate the precise clockrate control afforded by firewire? <br /> <br /> Or do those USB->SPDIF units have the ability to receive an external clock rate like the Lynx? I was previously using coax SPDIF output with and M-audio audiophile 192 PCI card, which was pretty good. It, like the Lynx, can receive input from an external source such as the DAC202, for a more precise jitter control. But Chris felt that with the DAC202, this (externally clocked) SPDIF performance was SECOND to firewire.....
  14. Sorry for some of the typo errors:<br /> <br /> To clarify, I am comparing relative sound qualitiy of laptop<->DAC202 vs ultra desktop<->DAC202, AFTER, I eliminated all the "pop and click" artifacts from DPC latencies on the laptop. Both have bit perfect stream, according to the DAC202's testing utility.<br /> <br /> <br /> <br />
  15. Hi Chris: I would like to tap into your experience with firewire links for an opinion of a few questions:<br /> <br /> I recently sent you a note about how happy I am with the DAC202. My very first installation on the computer end is on my current working desktop, which is a fairly up to date, relatively high end machine:<br /> <br /> ASUS P6T m/b, based on the X58 chipset;<br /> i7-930 Intel CPU<br /> 12 gigs of ram<br /> Patriot 128g SSD for the OS; 600 gigs of HD space in RAID0 via 2 Western Digital 300g raptor drives.<br /> on board firewire 400 chip from VIA: VIA VT6315N PCIe<br /> 2 PCIe DVI graphics cards, to drive 4 HD monitors, for a huge desktop space.<br /> <br /> <br /> The machine is a monster! All of the superlatives I confirmed in my prior note were from using this desktop, to feed the DAC202.<br /> <br /> I then tried to revive some older laptops and desktops with firewire ports, because I don't want to use my working desktop for music. As you know, there are lots of issue with getting firewire to work on other machines with different chipsets. The biggest one that plagues laptop users is the problem of prolongued DPC latencies, which produce "click and pop" artifacts in the analogue output from the DAC. You have to do much work to find, eliminate or update the culprit processes.<br /> <br /> To summarize: After resolving all issues of DPC latencies, so that there are "click and pop" artifacts, no visible excessive DPC latencies reported by the DAC202's own monitering program, aftering passing the DAC202's bit transparency test, HD music fed via firewire STILL sounds better coming from my monster desktop, when compared to the same sources coming from a laptop (DELL latitude 820) or older desktop with an PCI firewire card.<br /> <br /> I kept telling myself that this is NOT possible, but still I can hear the difference: more detail and clarity from the more power desktop! After listening with the laptop for a while, I began questioning my initial impressions of the DAC202: good but ??? great???? It was only after going back to the desktop that I realized the difference between the two computers. If the bitstream is confirmed to be bit perfect, and assuming that the firewire protocol has virtually eliminated siginficant jitter, I don't understand how there can possibly BE a difference.<br /> <br /> <br /> Question:<br /> <br /> Have others noticed differences in SOUND QUALITY (not noise or artifacts) when using firewire from different machines/chipsets ?? <br /> <br /> If so, are some chipsets known to give better performance than others?<br /> <br /> The practical reason for questioning is that I want to build a small, silent, PC such as your C.A.P.S., optimized for firewire and the DAC202. Oviously, I want to use a chipset and platform that is known to work well. So far, for me, that would comprise a machine built on the ASUS P6T m/b on a Win7 64x platform. I'm SURE this must be overkill, but I would do it, if that was my only option. (I would rather stay OFF the MAC platform, if possible.)<br /> <br /> Thank you in advance for any suggestions you can provide. I apologize if this is the wrong forum for my questions.<br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br />
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