i've been led to believe that optical is less prone to electrical/RF interference than coax or usb. it's also better for longer runs. however, i believe coax has more bandwidth, and makes a more secure physical connection than optical, so i usually go for coax.
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System-dependent, because it depends on implementation quality at both ends.
DSD or fs > 192 kHz usually requires USB.
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Someone correct me if I’m wrong, but it seems like I read that most dacs require USB connection for asynchronous functionality. |
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Whatever sounds best to you. EVERY setup is different. |
Bluesound Node 2i to Benchmark DAC 3 b |
Bluesound Node 2i to Benchmark DAC 3 b 1.25 to 2 meter reasonable quality 75 ohm coax |
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no
shorter than 1 m coax runs risk of reflections in the transmitted square wave signal... that is why best length is 1.25 m or longer |
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I ordered 1M..can you share documentation of this phenomena? |
op
do what you want... research it if you really want to understand, you have google on your laptop or i-pad or phone, right?
you come here asking a question, we take the time to give you the right answer, we owe you no proof
give me a break |
Jjss49.
Maybe you should give the OP a break. He asked you a civil and legit question. I would question the reason for specific length of coax too. |
you can research it too... he asked, i answered trying to be helpful, and i told him why... then he says prove it, to that i say no thanks, that’s why there is google (and a search bar at the top of this very page) - i am done being helpful at this point - my info isn’t suspect because you hastily ordered a 1 m cable before you got the proper answer to your query...
you guys buy whatever length you want... really... hardly matters to me... |
If it all comes down to sound quality, I'd be willing to bet you couldn't hear the difference between a 1 meter coax connection to the 1.25 length. Not being snarky, just say'in....
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jw944ts, When cable impedance is perfectly matched to DAC then length of the cable doesn't matter, but when it is mismatched then you'll get reflection from the end of the cable. This reflection originates from the beginning of the transition (knee) and might come back exactly at the middle of it, where level change is recognized, possibly shifting it in time. We can avoid it by delaying reflected signal using longer cable. For typical dielectric electricity moves at about 2/3 of the light speed - about 5ns/m. With 1.5m cable reflection will come back at 3m*5ns/m=15ns just missing half of typical 25ns transition. When transition is longer, for instance 30ns than you need 2m cable, but when it is shorter than 1m might be enough. Hard to predict and almost impossible to measure, so the best way is to try. 2m sounds like the safest choice, but it is a little more prone to electric ambient noise. For DAC3 I would use USB, but again the best is to try.
Optical has slow transitions making point of level recognition (threshold) unstable in presence of system noise on either end. The benefit, of course, is electric ambient noise immunity and no ground loops. I use inexpensive glass Toslink having both ends (DAC3 and Airport Express) plugged into conditioner (don't have USB source). In addition DAC3 has strong jitter suppression. Hope it helps. |
@jjss49 , my polite request was out of intellectual curiosity, and my tendency not to believe things just because someone says something. I sorry to have made you SO defensive...I thank you and @kijanki for the information....
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@jw944ts
hardly defensive, just irritated
no one here is your information butler, serving stuff you want on a silver platter on demand
search the site if you want background info... you can figure any basic question you have has been answered before -- that is why each a-gon page starts at the very top with the search bar
just type "proper length digital cable" in it, see what happens if you doubt what folks trying to help you with the correct answer are saying -- it’s like magic!
instead of saying - ’show me documentation of your assertion...’ |
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for what it is worth to those on this tread, I am now aware there are some articles about this subject, but interestingly, neither my DAC or cable manufacturer recognize this as an issue.....I would certainly think they would if it was a significant issue, as it would cause consternation about their products and the resulting sound.... |
USB best. No documentation to prove it. Just lots of testing. And if you want to listen to DSD, which is to be recommended as it sounds better if a genuine DSD recording (ie not simply upsampled) then you need USB. |
“Somebody” needs to switch to decaf …
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OP. I'm with you on this one. Nothing wrong with a question to learn. Some people are extremely touchy and sensitive. The proof is in the pudding, and that is, how does it sound??? :-))) |
I read this thread with some interest as I am upgrading my DAC and am interested in the question posed. It sure seems to me the question was answered in a durect and helpful way, and the original poster is somewhat belaboring the point after receiving the answers, maybe not hearing what he wanted to hear. We who use the internet and internet forums to get assistance for our own uses should have some basic research and searching skills to get more information to satisfy their curiosities. Especially since we all know that there is a great deal of misinformation on the net, and who knows who has what stake in giving their answer. |
further inquiries to the manufacturer of my DAC, (Benchmark DAC 3B), I have this response.... From engineering and designer of the DACs: Yes, the DAC1, DAC2 and DAC3 converter have the UtraLock, UltraLock2, and UltraLock3 jitter attenuation systems that remove incoming jitter. There is never any jitter-induced distortion no matter what cable length is used. we can chose to believe what we wish, and/or trust our ears....thank you |
@jw944ts
Facepalm is right, geeezzzzus. Your response was totally neutral in asking for additional info out of curiosity. Nothing more. You weren't asking to be spoon fed, cripes. This read like some road rage. Just keep scrolling.
Anyway, as others have mentioned its really always about implementation. Way too many variables to say interface X is the best, its impossible. Inquiring to the manufacture is probably the best place to ask as well as providing them you workflow/signal chain => if you do a lot of hi rate up-sampling for example, USB/i2s is usually the interface of choice.
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