TC_Shadow Posted November 12, 2009 Report Posted November 12, 2009 What's the best method of connecting transport to DAC via either spdif or aes/ebu encoding, in real life? I have the option of doing one of the following (from transport -> DAC): 1. BNC 75 -> RCA ~75 2. RCA ~75 -> RCA ~75 3. XLR 110 -> XLR 110 4. toslink -> toslink I have been going through my emag book and coax is theoretically the perfect medium at transmitting high-frequency signals over a length of 1M. I have been trying different combination with blue jeans cable, and they all sound different. So what's objectively the best connection in the real world?
Dusty Chalk Posted November 12, 2009 Report Posted November 12, 2009 Recently learned that RCA is physically impossible to meet spec, so, one of the other two. I suspect XLR, but haven't had any problems with Toslink that others seem to have.
Grahame Posted November 12, 2009 Report Posted November 12, 2009 AES/EBU is probably going to be the best, assuming that everything is actually at the correct resistance. Some people disagree "AES/EBU doesn't fix anything in s/pdif, it makes it worse. It uses wiring and connectors that lack the bandwidth and impedance matching for RF signaling. Just because XLRs are suitable for analog audio doesn't make them good for high frequencies. It's included on Transporter frankly because of legacy expectations, and perhaps in a pro environment you might need it for one reason or another (got the cable handy, used up all the other inputs, etc) but I don't recommend it. Squeezebox : Community : Forums - View Single Post - Help: Best new device for audiophile with DAC? "Its nice to know someone else agrees with me about AES EBU, I always thought I was the lone voice in the wilderness. Anyway I see two main reasons for the inferiority of AES/EBU. 1. XLRs are horrible RF connectors. In order to send a square wave fairly faithfully the interface must support a bandwidth many times higher than the frequency of the square wave. For the signals in question that is getting well up into the RF spectrum where the XLRs are terrible. The impedance varies radically with frequency which will cause all kinds of bizarre reflections. The choice of XLR was a very poor choice. 2. Output voltage. The S/PDIF electrical spec is 0.5V into 75ohms, but the AES/EBU is 3-5V into 110 ohms. Think about that for a second, what happens when you put 5volts across 110 ohms? You get almost 50mA of current flowing. This means the driver sitting in the source box has to be able to dump between 30-50ma into the cable. That causes huge current spikes in the power and ground pins of the driver chip which is going to cause big noise spikes in the power and ground planes of the board. If you are not extremely careful that is going to cause significant jitter in the output signal. All modern high speed interfaces use less than 0.5V signal. As far as I can tell the XLRs were chosen because studios had lots of microphone cables and wanted to use them. Because they are such lousy RF transmission lines they had to go with high voltages to make sure there was some signal left at the end. John S. " Squeezebox : Community : Forums - View Single Post - Help: Best new device for audiophile with DAC?
Dusty Chalk Posted November 12, 2009 Report Posted November 12, 2009 I think you should try all four and tell us if you can hear the difference. Use glass for the toslink -- you don't need to get expensive glass, but you do need to be especially careful with it.
TC_Shadow Posted November 12, 2009 Author Report Posted November 12, 2009 I think you should try all four and tell us if you can hear the difference. Use glass for the toslink -- you don't need to get expensive glass, but you do need to be especially careful with it. There is a difference between RCA and XLR, with XLR being the softer sounding of the 2. The one concern I have with toslink is that I have a number of 24/96 files and that's almost at the limit of toslink transmitter/receiver bandwidth. So is my best option BNC -> RCA (I know there will be a little reflection from the DAC due to the RCA connector)?
luvdunhill Posted November 12, 2009 Report Posted November 12, 2009 DO WE NEED ANYMORE THREADS TALKING ABOUT DIGITAL CABLES?
Pars Posted November 12, 2009 Report Posted November 12, 2009 Threads? Polls, yes, of course... threads, no.
manaox2 Posted November 12, 2009 Report Posted November 12, 2009 How does one justify stereotyping the sound of different connectors? I see listing strengths such as BNC keeps impedance in spec, etc. But saying that coaxial RCA when speaking to the effects of jitter universally sounds "softer" then AES sounds to me like total horse shit.
TC_Shadow Posted November 12, 2009 Author Report Posted November 12, 2009 How does one justify stereotyping the sound of different connectors? I see listing strengths such as BNC keeps impedance in spec, etc. But saying that coaxial RCA when speaking to the effects of jitter universally sounds "softer" then AES sounds to me like total horse shit. that was my reply to a question asking if I had tried different cables using the above mentioned connectors (based on what I have and what I heard, XLR was the softer one). I don't know where you get the idea that all XLR sound softer than all coax -> I am not so stupid as to make that assertion based on my limited sampling of cables with an even more limited supply of sources.
Beefy Posted November 12, 2009 Report Posted November 12, 2009 How does one justify stereotyping the sound of different connectors? I see listing strengths such as BNC keeps impedance in spec, etc. But saying that coaxial RCA when speaking to the effects of jitter universally sounds "softer" then AES sounds to me like total horse shit. Improvements from digital cabling always include tighter bass......
TC_Shadow Posted November 12, 2009 Author Report Posted November 12, 2009 Improvements from digital cabling always include tighter bass...... is that true? if so why?
Beefy Posted November 12, 2009 Report Posted November 12, 2009 is that true? if so why? Its not true. Its audiophool bullshit. Perhaps I should have added sarcasm tags to let you know that I was making fun of you?
manaox2 Posted November 12, 2009 Report Posted November 12, 2009 that was my reply to a question asking if I had tried different cables using the above mentioned connectors (based on what I have and what I heard, XLR was the softer one). I don't know where you get the idea that all XLR sound softer than all coax -> I am not so stupid as to make that assertion based on my limited sampling of cables with an even more limited supply of sources. My mistake. So what's objectively the best connection in the real world? I think your answer is 'depends' I guess is what I am saying. You didn't give us any information and your asking us to stereotype these connectors to prove which is best. I'm not sure anyone without your equipment is really going to be able to help you in this case. Different transports, receivers and sources. I think you did the right thing testing yourself, would have been better without the thread about it.
Sherwood Posted November 12, 2009 Report Posted November 12, 2009 I hereby designate "fixedsys" the sarcastic font.
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