[SlimDevices: Audiophiles] Re: SPDIF question - error correction and interconnect quality
konut Wrote: Rereading this thread convinces me that my money is better spent upgrading the on board electronics of the SB3 rather than trying to implement an external DAC. What are already very good circuits can be improved to excellent with a relatively modest sum compared to the added complexity and expense of an external solution with comparable performance. just a side note... i am not fully convinced that running DAC chips direct to the RCA jacks as many suggest is the best idea. i am running a similar DAC chip in my Sony CD/SACD player like this right now, and i've also done this to a Panasonic DVD player which uses a chip practically identical to the SB. while it sounds nice, i do miss the additional drive capability i had with the opamp output buffer... the output level is quite low, and i am missing some oomph and depth to the sound. numerous power supply tweaks have improved matters, but it's still a little on the weak side. another issue is the lack of output filtering. the Burr-Brown chips have a very basic 1st order analog filter. additional filtering is desirable to suppress PWM noise from the bitstream conversion process. left unfiltered, it may cause stability problems with some systems. my system seems alright, but i haven't checked with a 'scope, and i feel it might be adding some residual brightness and noise the sound. at the very least you would want to add a simple RC filter to get the effective response to be 2nd order, but the limited drive capability of the DAC output pretty much rules out doing this passively. i have removed all shunt capacitance from the output of the chip as it really kills the sound. still, i suppose compared to a mediocre output section (and obviously the stock one on the SB), the direct DAC method has advantages in sound quality. anyway, an external DAC with a better analog section, despite the drawbacks of S/PDIF, may still yield some sonic advantages due to the analog limitations of the SB. -- dorkus dorkus's Profile: http://forums.slimdevices.com/member.php?userid=3373 View this thread: http://forums.slimdevices.com/showthread.php?t=21415 ___ audiophiles mailing list audiophiles@lists.slimdevices.com http://lists.slimdevices.com/lists/listinfo/audiophiles
[SlimDevices: Audiophiles] Re: SPDIF question - error correction and interconnect quality
Red Wine Audio recently changed its mod set to the SB2/3. Vinnie is now substituting a BB OPA2604 for the NJM2041 opamp. Details of the changes can be found here. http://www.redwineaudio.com/SB2_SB3_Mods.html I had originally ordered mine SB3from Vinnie the at the end of Nov. but had told him to hold off on shipping it because I use a passive pre in my system and was on the fence weather to get the digital mod only or the full mod. I couldn't be happier at the changes he's made and I should be getting it in a couple of weeks. -- konut konut's Profile: http://forums.slimdevices.com/member.php?userid=1596 View this thread: http://forums.slimdevices.com/showthread.php?t=21415 ___ audiophiles mailing list audiophiles@lists.slimdevices.com http://lists.slimdevices.com/lists/listinfo/audiophiles
[SlimDevices: Audiophiles] Re: SPDIF question - error correction and interconnect quality
konut Wrote: Red Wine Audio recently changed its mod set to the SB2/3. Vinnie is now substituting a BB OPA2604 for the NJM2041 opamp. i'm sure the OPA2604 is an improvement over the NJM2041 (what wouldn't be), but i have serious doubts about how well any drop-in replacement could perform given the existing 5V supply rail. i consider even the +/-7V rails in my Sony player to be a severe limitation, and that's nearly 3x the swing. also, the OPA2604 is not particularly transparent as far as opamps go, but perhaps it is more insensitive to implementation than the higher-performance, twitchier parts. anyway, let us know how it sounds when you get it back. -- dorkus dorkus's Profile: http://forums.slimdevices.com/member.php?userid=3373 View this thread: http://forums.slimdevices.com/showthread.php?t=21415 ___ audiophiles mailing list audiophiles@lists.slimdevices.com http://lists.slimdevices.com/lists/listinfo/audiophiles
[SlimDevices: Audiophiles] Re: SPDIF question - error correction and interconnect quality
Actually, I know there will always be some reflections, as nothing is perfect, but I plan to do what I can to minimize the reflections. You want one of these then :- http://tinyurl.com/o4cbl Andy. -- Andrew L. Weekes Andrew L. Weekes's Profile: http://forums.slimdevices.com/member.php?userid=573 View this thread: http://forums.slimdevices.com/showthread.php?t=21415 ___ audiophiles mailing list audiophiles@lists.slimdevices.com http://lists.slimdevices.com/lists/listinfo/audiophiles
[SlimDevices: Audiophiles] Re: SPDIF question - error correction and interconnect quality
Patrick Dixon Wrote: I don't think things are that simple: if you have a mismatch at both ends (which you probably will) the reflection will bounce back and forth along the cable as it decays. What if I have 75 ohm BNC's at both ends, and have optimized the SB tx circuit, and my dac rx circuit to make sure they are set at 75 ohms, and don't create reflections. Actually, I know there will always be some reflections, as nothing is perfect, but I plan to do what I can to minimize the reflections. Randy -- randytsuch randytsuch's Profile: http://forums.slimdevices.com/member.php?userid=3783 View this thread: http://forums.slimdevices.com/showthread.php?t=21415 ___ audiophiles mailing list audiophiles@lists.slimdevices.com http://lists.slimdevices.com/lists/listinfo/audiophiles
[SlimDevices: Audiophiles] Re: SPDIF question - error correction and interconnect quality
Rereading this thread convinces me that my money is better spent upgrading the on board electronics of the SB3 rather than trying to implement an external DAC. What are already very good circuits can be improved to excellent with a relatively modest sum compared to the added complexity and expense of an external solution with comparable performance. Had Slim Devices chosen to target a more restricted (read higher end) part of the market, I'm sure they would have come up with a higher performance product as well. -- konut konut's Profile: http://forums.slimdevices.com/member.php?userid=1596 View this thread: http://forums.slimdevices.com/showthread.php?t=21415 ___ audiophiles mailing list audiophiles@lists.slimdevices.com http://lists.slimdevices.com/lists/listinfo/audiophiles
[SlimDevices: Audiophiles] Re: SPDIF question - error correction and interconnect quality
Andrew L. Weekes Wrote: It represents an impedance discontinuty that will give rise to reflections that are serious enough to impact the performance of SPDIF. It's specific location is largely irrelevant here - a mismatch is a mismatch is a mismatch.The closer the impedance anomaly is to the transmitter or receiver, the closer the reflection is to the incident edge. In a 100ns pulse, a reflection at a 1ns delay may not even be picked up, but a reflection at a 50ns delay would probably cause problems. -- John Stimson John Stimson's Profile: http://forums.slimdevices.com/member.php?userid=218 View this thread: http://forums.slimdevices.com/showthread.php?t=21415 ___ audiophiles mailing list audiophiles@lists.slimdevices.com http://lists.slimdevices.com/lists/listinfo/audiophiles
[SlimDevices: Audiophiles] Re: SPDIF question - error correction and interconnect quality
Ask any comedian. Timing is EVERYTHING! -- konut konut's Profile: http://forums.slimdevices.com/member.php?userid=1596 View this thread: http://forums.slimdevices.com/showthread.php?t=21415 ___ audiophiles mailing list audiophiles@lists.slimdevices.com http://lists.slimdevices.com/lists/listinfo/audiophiles
[SlimDevices: Audiophiles] Re: SPDIF question - error correction and interconnect quality
ezkcdude Wrote: I have a hard time believing our ears can detect picosecond jitter when it's modulated by the DAC to produce distortion components in the audible spectrum, why not? -- dorkus dorkus's Profile: http://forums.slimdevices.com/member.php?userid=3373 View this thread: http://forums.slimdevices.com/showthread.php?t=21415 ___ audiophiles mailing list audiophiles@lists.slimdevices.com http://lists.slimdevices.com/lists/listinfo/audiophiles
[SlimDevices: Audiophiles] Re: SPDIF question - error correction and interconnect quality
Patrick Dixon Wrote: But the pulse width is not that important in an S/PDIF connection, it's the transitions that are. Reflections / impedance mismatches are rarely serious enough to cause actual data corruption (in S/PDIF), but they can affect the timing information contained in the rising and falling edges.If the reflection occurs close enough to the source or receiver, it can blend into the transition. Switching isn't instantaneous, and SPDIF isn't that high in frequency. The timing of a reflection can determine whether you see blurring of the edge/jitter in the clock, or visible artifacts/bit errors. -- John Stimson John Stimson's Profile: http://forums.slimdevices.com/member.php?userid=218 View this thread: http://forums.slimdevices.com/showthread.php?t=21415 ___ audiophiles mailing list audiophiles@lists.slimdevices.com http://lists.slimdevices.com/lists/listinfo/audiophiles
[SlimDevices: Audiophiles] Re: SPDIF question - error correction and interconnect quality
Hi Guys I thought if the reflections was close to the rx end, it could blur the transition. If it was far enough away to look like a discrete event, it was not likely to cause any harm. I have seen this as an argument to use a long digital cable, so any reflections are the tx end won't cause any degradation. Randy -- randytsuch randytsuch's Profile: http://forums.slimdevices.com/member.php?userid=3783 View this thread: http://forums.slimdevices.com/showthread.php?t=21415 ___ audiophiles mailing list audiophiles@lists.slimdevices.com http://lists.slimdevices.com/lists/listinfo/audiophiles
[SlimDevices: Audiophiles] Re: SPDIF question - error correction and interconnect quality
dorkus Wrote: regardless, if you cannot hear the differences, consider yourself very lucky. :) being able to hear all these little changes is a curse really. It was easy to hear the difference between that Philips chipset DAC (built in to the CD player) and the Lucid DA2496 until I did a blind test. The experience made me fundamentally re-think my approach towards evaluating audio equipment. -- cliveb cliveb's Profile: http://forums.slimdevices.com/member.php?userid=348 View this thread: http://forums.slimdevices.com/showthread.php?t=21415 ___ audiophiles mailing list audiophiles@lists.slimdevices.com http://lists.slimdevices.com/lists/listinfo/audiophiles
[SlimDevices: Audiophiles] Re: SPDIF question - error correction and interconnect quality
cliveb Wrote: It was easy to hear the difference between that Philips chipset DAC (built in to the CD player) and the Lucid DA2496 until I did a blind test. The experience made me fundamentally re-think my approach towards evaluating audio equipment. quick A-B blind tests are not very instructive, as they tend to make it very difficult to make out anything but the most egregious differences in sound quality. blind tests in and of themselves are fine, but they have to be done over prolonged periods (days, even weeks) so the sound of each method can adequately sink in. long-term listening can yield very different conclusions from short-term comparisons. if you rely on quick A-B testing to evaluate equipment, i think it might be difficult to achieve a high level of listening satisfaction in the long term. i review gear for an audio publication and very often i've heard stuff that wowed me in the first couple days of listening and in A-B tests, but ultimately left me unsatisfied when left in the system for the long haul. -- dorkus dorkus's Profile: http://forums.slimdevices.com/member.php?userid=3373 View this thread: http://forums.slimdevices.com/showthread.php?t=21415 ___ audiophiles mailing list audiophiles@lists.slimdevices.com http://lists.slimdevices.com/lists/listinfo/audiophiles
[SlimDevices: Audiophiles] Re: SPDIF question - error correction and interconnect quality
p.s. clive, i hope you don't think all i'm trying to do is contradict you at every opportunity. :) just trying to provide an alternative view of things in the hopes that it may help you get greater musical satisfaction out of your hi-fi. -- dorkus dorkus's Profile: http://forums.slimdevices.com/member.php?userid=3373 View this thread: http://forums.slimdevices.com/showthread.php?t=21415 ___ audiophiles mailing list audiophiles@lists.slimdevices.com http://lists.slimdevices.com/lists/listinfo/audiophiles
[SlimDevices: Audiophiles] Re: SPDIF question - error correction and interconnect quality
dorkus Wrote: p.s. clive, i hope you don't think all i'm trying to do is contradict you at every opportunity. :) just trying to provide an alternative view of things in the hopes that it may help you get greater musical satisfaction out of your hi-fi. As it happens, I do get a great deal of satisfaction from my hi-fi. For about 15 years I was a typical audiophile, forever seeking out better equipment to feed my habit. (In a sense, audiophilia is like an addiction). Then in 1993 I bought a new pair of speakers, and since then the urge to tinker and try out new things has practically disappeared. I put this down to the fact that when those speakers arrived, I had finally got to the point where my system was playing music instead of audio. For sure, I sometimes wonder whether something new is worth trying - hence the experiment with the Lucid DAC. But the bottom line is that I'm happy with the way it sounds and I have better things to do with my money. Meanwhile, I'll occasionally pop up in here to offer some objective ying to the subjectivists' yang. This thread started out as a discussion of SPDIF. My only intention in posting was to point out how amazingly robust the protocol is, and that people fret far too much about it. -- cliveb cliveb's Profile: http://forums.slimdevices.com/member.php?userid=348 View this thread: http://forums.slimdevices.com/showthread.php?t=21415 ___ audiophiles mailing list audiophiles@lists.slimdevices.com http://lists.slimdevices.com/lists/listinfo/audiophiles
[SlimDevices: Audiophiles] Re: SPDIF question - error correction and interconnect quality
hi clive, that's great that you're happy with your rig - that's a lot more than i can say for most audiophiles! cliveb Wrote: This thread started out as a discussion of SPDIF. My only intention in posting was to point out how amazingly robust the protocol is, and that people fret far too much about it. right, sorry for all the digressions. back to the subject at hand, and where my objection originally started. :) not to fan the flames of audiophile neurosis, but i actually do not think most people are not concerned ENOUGH with it. i'm guilty of this as well, i tend to just throw a belden coax in there and be done with it - i'm usually too lazy to fuss with it. but i've been using a single-box CD player for a few years now, so i haven't had to contend with the whole SPDIF ordeal. yes, SPDIF is very robust - that was clearly one of the original design objectives. however, i disagree that this robustness in data integrity translates to immunity to audible changes. this is not just a subjective evaluation, it is easily measurable as well. really, the best way is to avoid SPDIF altogether by using I2S (either internally as all CD players do, or externally to the DAC). but if you are stuck with it, it *is* worthwhile to play with different cables, connectors, tx/rx circuits, etc. to see if it makes a difference in sound quality, even in a resampling DAC like the Benchmark. the more i learn about how things work, the more i realize how little i actually know and how much knowledge and experience it takes before you can start to understand all the myriad phenomena at play in even the simplest of circuits. just perusing some of the in-depth technical discussions on the DIY sites has forced me to dust off the ol' EE college textbooks. cheers, dorkus -- dorkus dorkus's Profile: http://forums.slimdevices.com/member.php?userid=3373 View this thread: http://forums.slimdevices.com/showthread.php?t=21415 ___ audiophiles mailing list audiophiles@lists.slimdevices.com http://lists.slimdevices.com/lists/listinfo/audiophiles
[SlimDevices: Audiophiles] Re: SPDIF question - error correction and interconnect quality
John, Do you mean 75 Ohm? Yes. It seems that there are several manufacturers of 75 Ohm RCA connectors (Canare, et al) who would be highly vulnerable to false advertising suits if their product did not meet their published specifications. I don't know what they've published, but it is physically impossible, given teh physical dimensions of the connector, for an RCA Phono to be 75ohms and be able to plug into an RCA phono socket, period. Ask them for verified measurements as to the wideband impedance of the connector, and see what they come back with ;) The closer an impedance anomaly is to the sender or receiver, the less effect it will have. Why do you say that? It represents an impedance discontinuty that will give rise to reflections that are serious enough to impact the performance of SPDIF. It's specific location is largely irrelevant here - a mismatch is a mismatch is a mismatch. I would expect at least the high-end units to use something else if the RCAs didn't work. Well engineered units do, but the Sony/ Philips spec calls for RCA - for a manufacturer to use something else makes it not compliant with the SPDIF standard. Most manufacturers don't even realise it's important and the mismatch introduced by their SPDIF circuitry is so bad the RCA is just a factor in the equation. Dorkus, yes, i know they claim their UltraLock is completely immunte to input jitter, but that's what it is - a claim. if they showed spectral analysis of the jitter with varying input sources, that would lend it some credibility. [image: http://www.benchmarkmedia.com/dac1/D-A%20JITTER%20TOL.gif] The thing is this is just one spec the BM measures well on, who knows what the audible effect of the ASRC circuit is? Andy. -- Andrew L. Weekes Andrew L. Weekes's Profile: http://forums.slimdevices.com/member.php?userid=573 View this thread: http://forums.slimdevices.com/showthread.php?t=21415 ___ audiophiles mailing list audiophiles@lists.slimdevices.com http://lists.slimdevices.com/lists/listinfo/audiophiles
[SlimDevices: Audiophiles] Re: SPDIF question - error correction and interconnect quality
dorkus Wrote: ah, the wonders of marketing. yes, i know they claim their UltraLock is completely immunte to input jitter, but that's what it is - a claim. if they showed spectral analysis of the jitter with varying input sources, that would lend it some credibility. again, are you relying on pure theory, taking their word for it, or have you actually confirmed this with your own ears and/or seen measurements? I've seen measurements - granted they are from Benchmark's own website, so I suppose we should take them with a pinch of salt. And Andrew has pointed you at a relevant graph that shows varying input jitter has zero effect on distortion. This is exactly what you should expect given the asynchronous sample rate conversion method that Benchmark uses for its reclocking. As for my own ears: they're probably not good enough to discern any difference that may exist. In the past I've failed to discern the difference between a 1990 vintage Philips chipset 16bit 4x oversampling DAC and a 2000 vintage Lucid DA2496, in a blind test. Call me deaf if you like. Or alternatively consider the possibility that well-implemented digital technology already exceeded the limits of what's needed in a domestic playback environment many years ago, and that worrying about the last few picoseconds of jitter is akin to debating the number of angels that fit on the head of a pin. -- cliveb cliveb's Profile: http://forums.slimdevices.com/member.php?userid=348 View this thread: http://forums.slimdevices.com/showthread.php?t=21415 ___ audiophiles mailing list audiophiles@lists.slimdevices.com http://lists.slimdevices.com/lists/listinfo/audiophiles
[SlimDevices: Audiophiles] Re: SPDIF question - error correction and interconnect quality
'certainly not to my ears! :) but in this age of compressed music and ipods, i think people are not aiming very high anymore. i also feel that mp3s and headphones are the death of music and a bane to society, but that's another rant. :p' Well I still enjoy dragging a rock around a lump of plastic, which I guess gives my view on the state of 'modern' audio ;) Andy. P.S. I think you'll find the DAC1 is insensitive to jitter on the SPDIF, it's a function of ASRC, but I don't think that will tell you a lot about how it sounds overall! -- Andrew L. Weekes Andrew L. Weekes's Profile: http://forums.slimdevices.com/member.php?userid=573 View this thread: http://forums.slimdevices.com/showthread.php?t=21415 ___ audiophiles mailing list audiophiles@lists.slimdevices.com http://lists.slimdevices.com/lists/listinfo/audiophiles
[SlimDevices: Audiophiles] Re: SPDIF question - error correction and interconnect quality
dorkus Wrote: and btw, reclocking does not eliminate jitter, it just attenuates/shifts it.I think what you mean by reclocking here is what is commonly referred to as clock reconstitution, which is done by chips like the Crystal Semiconductor chip I referred to earlier. That takes the incoming clock signal and filters it to produce a clock signal with less jitter or with a different jitter spectrum. True re-clocking would involve storing the incoming data in a memory buffer, and then clocking the data out with a locally generated clock that isn't based on or otherwise influenced by the transport clock. If you do that, then there is no way for the jitter from the source to affect the timing of the data coming out of the buffer. You are in effect starting fresh, with only the jitter present in the local clock. That jitter can be very, very, very low if you take the care to do it right. -- John Stimson John Stimson's Profile: http://forums.slimdevices.com/member.php?userid=218 View this thread: http://forums.slimdevices.com/showthread.php?t=21415 ___ audiophiles mailing list audiophiles@lists.slimdevices.com http://lists.slimdevices.com/lists/listinfo/audiophiles
[SlimDevices: Audiophiles] Re: SPDIF question - error correction and interconnect quality
dorkus Wrote: i should think not. I hope you didn't take my tongue-in-cheek suggestion of using wet string literally. It's a standard joke used to describe situations in which high-quality cables/antennae/etc are not required. and btw, reclocking does not eliminate jitter. Genuine reclocking (of the type implemented by the Benchmark DAC1) does indeed *eliminate* the jitter on the incoming signal - and then of course replaces it with the characteristic jitter of the receiver's clock. The point here is that using such a DAC renders the jitter on the incoming signal irrelevant, which means as long as you don't get data errors it doesn't matter what cable you use. -- cliveb cliveb's Profile: http://forums.slimdevices.com/member.php?userid=348 View this thread: http://forums.slimdevices.com/showthread.php?t=21415 ___ audiophiles mailing list audiophiles@lists.slimdevices.com http://lists.slimdevices.com/lists/listinfo/audiophiles
[SlimDevices: Audiophiles] Re: SPDIF question - error correction and interconnect quality
John Stimson Wrote: True re-clocking would involve storing the incoming data in a memory buffer, and then clocking the data out with a locally generated clock that isn't based on or otherwise influenced by the transport clock. If you do that, then there is no way for the jitter from the source to affect the timing of the data coming out of the buffer. that's what i thought. common sense right? but then i read someone's observation that they tried this, and it was *still* only an attenuation affect, not complete isolation. yes, even with a reclocked FIFO RAM buffer. sounds unbelievable, but he had the measurements to back it up. you can also hear still hear differences in transports - e.g. the Chord DAC's have a buffer reclocking option, it does reduce the audible effect but you can still hear the difference between a good and bad transport. i can't remember where i saw the measurements, i will try to find them. -- dorkus dorkus's Profile: http://forums.slimdevices.com/member.php?userid=3373 View this thread: http://forums.slimdevices.com/showthread.php?t=21415 ___ audiophiles mailing list audiophiles@lists.slimdevices.com http://lists.slimdevices.com/lists/listinfo/audiophiles
[SlimDevices: Audiophiles] Re: SPDIF question - error correction and interconnect quality
Fortunately, high-bandwidth cable with the proper impedance isn't expensive or difficult to find. That's true, but similarly accurately engineered SPDIF inputs and outputs aren't so readily available ;) If they use an RCA phono (as the Philips standard specifies), you're immediately stuffed and can't do much about it. That's where most of the problem lies - there's no such thing as a 75R phono anywhere in the universe, no matter what any salesman might try and tell you :) Andy. -- Andrew L. Weekes Andrew L. Weekes's Profile: http://forums.slimdevices.com/member.php?userid=573 View this thread: http://forums.slimdevices.com/showthread.php?t=21415 ___ audiophiles mailing list audiophiles@lists.slimdevices.com http://lists.slimdevices.com/lists/listinfo/audiophiles
[SlimDevices: Audiophiles] Re: SPDIF question - error correction and interconnect quality
75R? Do you mean 75 Ohm, or 75 Ohm right angle? 1) RCA connectors are used for SPDIF and composite or component video in just about all consumer-grade A/V gear. I would expect at least the high-end units to use something else if the RCAs didn't work. Plus, you'd be able to see visible ringing on high-quality monitors (I can easily spot a cheapo VGA cable used with a computer monitor). 2) It seems that there are several manufacturers of 75 Ohm RCA connectors (Canare, et al) who would be highly vulnerable to false advertising suits if their product did not meet their published specifications. 3) The closer an impedance anomaly is to the sender or receiver, the less effect it will have. Since the RCA connector is generally placed very close to the sending or receiving circuit, that may provide the answer to #1, but not to #2. -- John Stimson John Stimson's Profile: http://forums.slimdevices.com/member.php?userid=218 View this thread: http://forums.slimdevices.com/showthread.php?t=21415 ___ audiophiles mailing list audiophiles@lists.slimdevices.com http://lists.slimdevices.com/lists/listinfo/audiophiles
[SlimDevices: Audiophiles] Re: SPDIF question - error correction and interconnect quality
cliveb Wrote: The only reason you might want to use good quality SPDIF connectors is to protect the signal from noise induced jitter, and that's only necessary if the receiving DAC doesn't reclock well. If you've got something like a Benchmark DAC1, you could probably use wet string. i should think not. a bit technical, but: http://www.diyhifi.org/forums/viewtopic.php?t=453 and btw, reclocking does not eliminate jitter, it just attenuates/shifts it. sometimes it can even make it worse. it really depends on the implementation and the circumstances. furthermore, reducing jitter doesn't necessarily translate to better sound quality. sometimes higher jitter can sound better. for instance if the spectral distrubition of the jitter is in a more innocuous part of the audible spectrum. sometimes it can even have a dither-like effect which sounds better in some systems. one must understand there is both quantity and quality to jitter. it's not just a matter of 1 or 0. my recommendation is to experiment with some different SPDIF cables and see if you can hear a difference. they don't have to be expensive, regular 75 ohm video cables will do just fine. use whatever you end up liking for whatever reason makes you happy, just try to have an open mind. the results may surprise you. -- dorkus dorkus's Profile: http://forums.slimdevices.com/member.php?userid=3373 View this thread: http://forums.slimdevices.com/showthread.php?t=21415 ___ audiophiles mailing list audiophiles@lists.slimdevices.com http://lists.slimdevices.com/lists/listinfo/audiophiles
[SlimDevices: Audiophiles] Re: SPDIF question - error correction and interconnect quality
Have a search on the forums for jitter. The thread http://forums.slimdevices.com/showthread.php?t=20675 started off as a discussion on the potential of using a USB connection, but branched out in all sorts of ways you may find interesting. Ceejay -- ceejay ceejay's Profile: http://forums.slimdevices.com/member.php?userid=148 View this thread: http://forums.slimdevices.com/showthread.php?t=21415 ___ audiophiles mailing list audiophiles@lists.slimdevices.com http://lists.slimdevices.com/lists/listinfo/audiophiles
[SlimDevices: Audiophiles] Re: SPDIF question - error correction and interconnect quality
S/PDIF does not realy fit into the usual ISO-OSI model but seems to have more in common with a layer 2 network protocol (e.g. ethernet). It does not use any error-correction. Details at http://en.wikipedia.org/wiki/S/PDIF (BTW: TCP/IP does not use error correction but re-sends, which on a faulty line leads to unpredictable transmission rates. Not something you would want for an audio signal) Lade -- lade lade's Profile: http://forums.slimdevices.com/member.php?userid=3180 View this thread: http://forums.slimdevices.com/showthread.php?t=21415 ___ audiophiles mailing list audiophiles@lists.slimdevices.com http://lists.slimdevices.com/lists/listinfo/audiophiles
[SlimDevices: Audiophiles] Re: SPDIF question - error correction and interconnect quality
gobikey Wrote: is there someone that knows digital audio transmission protocols that can comment? does S/PDIF use error correction? if not, i would completely understand the need for a high quality cable. i would also like to hear about anyone's experience with digital cable upgrades. As someone else has already pointed out, SPDIF does not use error correction. As a one-way protocol (ie. the receiver has no way of talking to the sender), you can't do resends a la TCP/IP. In that sense it's more like UDP than TCP. You might argue that the designers of the protocol should have included redundancy to assist in error correction. But as it happens SPDIF is an amazingly robust protocol. I've sent it over 50 feet of random thin COAX I had lying around (certainly not 75 ohm), terminated in cheap phono plugs (also certainly not 75 ohm) and got bit-perfect data transfers. Of course I'm sure that the jitter would have suffered were it feeding a DAC, but it wasn't so that's moot. The only reason you might want to use good quality SPDIF connectors is to protect the signal from noise induced jitter, and that's only necessary if the receiving DAC doesn't reclock well. If you've got something like a Benchmark DAC1, you could probably use wet string. -- cliveb cliveb's Profile: http://forums.slimdevices.com/member.php?userid=348 View this thread: http://forums.slimdevices.com/showthread.php?t=21415 ___ audiophiles mailing list audiophiles@lists.slimdevices.com http://lists.slimdevices.com/lists/listinfo/audiophiles
[SlimDevices: Audiophiles] Re: SPDIF question - error correction and interconnect quality
According to what I've read, SPDIF does not include re-clocking the data at the receiver, and even the high end Crystal Semiconductor (now Texas Instruments) only filter out clock jitter at high frequencies above the audio band. So unless you are sure that your DAC buffers and re-clocks the data with a low-jitter clock, it's probably a good idea to use a high-bandwidth cable with the proper impedance. Fortunately, high-bandwidth cable with the proper impedance isn't expensive or difficult to find. One of the Squeezebox guys pointed me to http://www.bluejeanscable.com/ which is a company that assembles RCA cables using high quality cable and connectors. You can also buy the parts yourself from http://www.zackelectronics.com/ . I made my own cables using Belden 1505F (or was is 1505A?) cable and Canare RCAP-C4F connectors. Boutique cable with freaky designs is likely to perform worse than this, because they're unlikely to have impedance that's as consistent and preceisely matched, or to support as much bandwidth. -- John Stimson John Stimson's Profile: http://forums.slimdevices.com/member.php?userid=218 View this thread: http://forums.slimdevices.com/showthread.php?t=21415 ___ audiophiles mailing list audiophiles@lists.slimdevices.com http://lists.slimdevices.com/lists/listinfo/audiophiles
