When my Pioneer DV-535 DVD/CDA player started to fail, after trying to repair it and failing, I went looking for a new CDA player. But, the market (when not!) had already stopped the production of these dual DVD/CDA players, and exclusive CDA players like Marantz had very high prices. Streaming music and Netflix movies were here to stay!
So I bought a product made in China, which had on its forehead a brand that was synonymous with quality at the time. I'm talking about Philco. I remember that after putting together several TV kits in my beginnings as a technician - the ones that copied the original Wells Gardner circuit - and having cursed for that 50 C/S oscillation (here
in Argentina, in the USA and other countries it is 60 Hertz, as you know ) on the screen that refused to disappear after changes of rectifier tubes, filter capacitors, etc. , I bought an original Philco TV for personal use - manufactured here under license and strict quality control - I never saw such a high quality black and white image in those years! (Possibly Westinghouse would have been, but it was never made here).
So the Chinese generic outfit "Philco" manufactured wholesale and with the brand and model "on request" that I bought, - DVP-500 -, ultra thin, fashion rules, they call it "slim" has been working perfectly a few years ago Already.
I have to admit that it has an excellent behavior as a CDA player, MP3 player; WMA etc The big drawback is its slow process for selecting tracks and the poor information on the display. And well, for the money it cost, you couldn't ask for more, that's clear to me. As a DVD player, very limited too, but since the Optoma projector blew up, there was no more cinema in my home.
Having said all this, and having used the optical connection from the beginning and coupled the Philco to an Oppo Sonica Dac, - the idea was to use it as a transport and take advantage of the virtues of the ES9038PRO chip of the Oppo Sonica DAC -, I had a doubt.
Lately I have read that to listen to music the coaxial cable connection is better than the optical one ..... and a demanding audiophile like me cannot ignore this just like that!
Delving deeper into the subject, in favor of the optical cable is the null interference of nearby electromagnetic fields, and against its lower bandwidth, also against the fact that the cable should not be bent, and the poor quality of many "generic" cables that in instead of a crystal center conductor they use plastic, which would degrade the entire bit path. Well I use the one that came with the Pioneer.......
In favor of the coaxial cable we have a greater bandwidth, against which it is prone to pick up electromagnetic signals from nearby equipment and that the cable must have a characteristic impedance of 75 Ohms, so common analog interconnection cables should not be used. RCA.
Thinking ? Am I missing some SQ (sound quality) when using the optical connection? I want to do the experience, should I buy a specific "boutique" coaxial cable or is it the same to prepare one with a generic 75 Ohm cable and two RCA connectors?
So I bought a product made in China, which had on its forehead a brand that was synonymous with quality at the time. I'm talking about Philco. I remember that after putting together several TV kits in my beginnings as a technician - the ones that copied the original Wells Gardner circuit - and having cursed for that 50 C/S oscillation (here
in Argentina, in the USA and other countries it is 60 Hertz, as you know ) on the screen that refused to disappear after changes of rectifier tubes, filter capacitors, etc. , I bought an original Philco TV for personal use - manufactured here under license and strict quality control - I never saw such a high quality black and white image in those years! (Possibly Westinghouse would have been, but it was never made here).
So the Chinese generic outfit "Philco" manufactured wholesale and with the brand and model "on request" that I bought, - DVP-500 -, ultra thin, fashion rules, they call it "slim" has been working perfectly a few years ago Already.
I have to admit that it has an excellent behavior as a CDA player, MP3 player; WMA etc The big drawback is its slow process for selecting tracks and the poor information on the display. And well, for the money it cost, you couldn't ask for more, that's clear to me. As a DVD player, very limited too, but since the Optoma projector blew up, there was no more cinema in my home.
Having said all this, and having used the optical connection from the beginning and coupled the Philco to an Oppo Sonica Dac, - the idea was to use it as a transport and take advantage of the virtues of the ES9038PRO chip of the Oppo Sonica DAC -, I had a doubt.
Lately I have read that to listen to music the coaxial cable connection is better than the optical one ..... and a demanding audiophile like me cannot ignore this just like that!
Delving deeper into the subject, in favor of the optical cable is the null interference of nearby electromagnetic fields, and against its lower bandwidth, also against the fact that the cable should not be bent, and the poor quality of many "generic" cables that in instead of a crystal center conductor they use plastic, which would degrade the entire bit path. Well I use the one that came with the Pioneer.......
In favor of the coaxial cable we have a greater bandwidth, against which it is prone to pick up electromagnetic signals from nearby equipment and that the cable must have a characteristic impedance of 75 Ohms, so common analog interconnection cables should not be used. RCA.
Thinking ? Am I missing some SQ (sound quality) when using the optical connection? I want to do the experience, should I buy a specific "boutique" coaxial cable or is it the same to prepare one with a generic 75 Ohm cable and two RCA connectors?
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They both have their evils but the coax goes through fewer conversions. From electricity to light and back again making more places to screw up the signal. If you are in RF and EM hell then the optical might be the way to go. Find some Belden 1694A coax and roll your own cables with the connectors of you choice. It’s a little stiff but it’s what we use in the broadcast industry to move HD audio and video. There are lots of other good ones by Canare etc..
Belden is indeed fine coax but it's so stiff it would be unwieldy around the back of the
units and may even break the RCA connectors mounted directly to PCBs. As far as
'conversions' , the disc player might (or not) send the data directly in which case the
conversion to analog would be at the preamp/receiver. Never any ground loops with
optical.
G²
I like my SACD DV59aviPioneer through its stereo L&R coaxial until I plug thorough a up to date moderized Dac and by pass the dual Burr Browns inside. Imagine those were cutting edge back in the earlier 0000's. This one and that are cracking good players, I always stuck with Pioneer mostly. The 59 is one of the best transports Pioneer put out even to this day.
Otherwise I feed the digital coax through the Dac. Sometimes its hard to beat the redbooks and a solid player no matter how much resolution you throw at the thing 🙂
Otherwise I feed the digital coax through the Dac. Sometimes its hard to beat the redbooks and a solid player no matter how much resolution you throw at the thing 🙂
When you draw a block diagram of your equipment with all ground connections (signal ground, protective earth, CATV cable ground), you can probably figure out whether a coaxial S/PDIF connection is going to cause ground loops. If not, just use a coaxial connection.
Optical so Toslink wins in terms of jitter big time. It is in most cases much much worse than coax SPDIF and in the range of hundreds of picoseconds to almost 1 ns. Only manufacturers that give "special attention" have overcome this one way or another. In most cases listening makes immediately clear that Toslink is worse. It won't take more than a minute even 🙂 Please use 75 Ohm cable of normal industrial quality.
A media player is a good alternative to DVD players. Optical media are old fashioned. You'll get high res for free and USB output to the Oppo with that. In some cases USB is better than SPDIF over coax (but not always). Of course the best approach is a device that does not need an external DAC and interface at all but that has an internal high quality DAC.
A media player is a good alternative to DVD players. Optical media are old fashioned. You'll get high res for free and USB output to the Oppo with that. In some cases USB is better than SPDIF over coax (but not always). Of course the best approach is a device that does not need an external DAC and interface at all but that has an internal high quality DAC.
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for coaxial s/pdif connection, a high quality 75 ohm "RG-59" video cable with decent RCA connectors works just fine, Belden 1694A is too stiff, Belden 1505F (about 6mm O.D) used for SDI digital / HDTV video should work and is more flexible / lighter than the 1694A.
Thank you all for the answers.
I will try to build a coaxial cable with a piece of 75 Ohm cable of the type used in home installations. I think it's the RG-59. I will look for one as flexible as possible, I have many scraps out there. I guess the length shouldn't matter because it transmits bits, but anyway I'll make it just the right length to get from one artifact to the other comfortably, without too much leftover, which is always a hassle.
So, will there be a difference in sound quality with respect to optical?
I will try to build a coaxial cable with a piece of 75 Ohm cable of the type used in home installations. I think it's the RG-59. I will look for one as flexible as possible, I have many scraps out there. I guess the length shouldn't matter because it transmits bits, but anyway I'll make it just the right length to get from one artifact to the other comfortably, without too much leftover, which is always a hassle.
So, will there be a difference in sound quality with respect to optical?
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SPDIF carries both digital bits and analog timing reference information. Its the analog timing part that tends to degrade first.
SPDIF is an analog signal carrying digital information. Length does matter but it is more depending on the quality of the terminations. Longer cable may in fact have less reflections. I doubt your connectors or PCB tracks at either end are truly 75 ohm. The impedance of the connecting cable does not then help much.
" The impedance of the connecting cable does not then help much."
🤔
https://en.wikipedia.org/wiki/Characteristic_impedance
🤔
https://en.wikipedia.org/wiki/Characteristic_impedance
So what's the use of cable impedance if terminations are not properly implemented?
As long as the traces and connectors with incorrect impedance are electrically short, that is, much shorter than the distance that the signal travels within its rise time, they don't have much impact. The cables can be many metres long, the PCB traces not.
But unless your terminations and connectors are not 75 ohm what is the use of 75 ohm cable instead of let's say normal RCA?
Besides proper terminations and connectors are for minimizing reflections which is important for low jitter SPDIF.
The terminations are 75 ohm, 75 ohm +/- 5 % to be standard compliant if I remember well. The connectors are electrically very short, so they hardly have any impact. (It would be a different matter if this were some GHz-range transceiver, as almost anything is too large to be considered electrically short then.) The cable could be long enough not to be electrically short.
What terminations are you referring to here? We are not talking about standards but terminations in Philco and Oppo.
I mean the termination resistors inside equipment with IEC 60958-1-compliant S/PDIF inputs and outputs. I assume Philco and Oppo are professional enough to ensure that their equipment is standard compliant.
Chapter 7.1 of IEC 60958-1 (at least the version from 2006 that I have access to) specifies a termination impedance of 75 ohm +/- 5 % at the receiving end and an impedance of 75 ohm +/- 20 % at the transmitting end for frequencies from 100 kHz to 128 times the maximum frame rate. For stereo uniformly-quantized PCM, the frame rate is simply the sample rate.
If, for example, the equipment supports sample rates up to 192 kHz, 128 times the maximum frame rate is 24.576 MHz. In a cable in which waves propagate with a velocity of 200 000 km/s, the wavelength of 128 times the maximum frame rate is then 8.138 m. The first transmission line resonance occurs when cable is 1/4 wavelength long, so cables have to be much shorter than 2.0345 m to be considered electrically short. Most cables won't meet that, but a cinch connector of a few centimetres is definitely electrically short.
By the way, IEC 60958-1 specifies a cable characteristic impedance of 75 ohm +/- 35 %. Even a 50 ohm cable can still meet that (only just). I'm sure the jitter will be better when you use a more accurate characteristic impedance, though.
Chapter 7.1 of IEC 60958-1 (at least the version from 2006 that I have access to) specifies a termination impedance of 75 ohm +/- 5 % at the receiving end and an impedance of 75 ohm +/- 20 % at the transmitting end for frequencies from 100 kHz to 128 times the maximum frame rate. For stereo uniformly-quantized PCM, the frame rate is simply the sample rate.
If, for example, the equipment supports sample rates up to 192 kHz, 128 times the maximum frame rate is 24.576 MHz. In a cable in which waves propagate with a velocity of 200 000 km/s, the wavelength of 128 times the maximum frame rate is then 8.138 m. The first transmission line resonance occurs when cable is 1/4 wavelength long, so cables have to be much shorter than 2.0345 m to be considered electrically short. Most cables won't meet that, but a cinch connector of a few centimetres is definitely electrically short.
By the way, IEC 60958-1 specifies a cable characteristic impedance of 75 ohm +/- 35 %. Even a 50 ohm cable can still meet that (only just). I'm sure the jitter will be better when you use a more accurate characteristic impedance, though.
And lots of jitter but tube guys apparently seem to like that 🙂 With a good SPDIF receiver jitter can be lower than 75 ps via coax. With Toslink it is hundreds of picoseconds even with original Toshiba ones.
Ground loops are very easy to avoid (by design) and many devices already have pulse transformers for coax SPDIF that do a fine job of galvanic separation so the ground loops are likely not caused by SPDIF over coax but by design errors elsewhere. So the choice for the worst interface is made for the wrong reason.
A dedicated audio device that plays music files from either a NAS or, when one is not too keen on networked devices, from a USB stick or external SSD so no electrical motor or laser that wears out. When using a 256 gb USB stick one can have many albums accessible. Like the CD player once took the market today the media player/audio player takes its place. Examples: Bluesound N130, Elac DS-S101-G, Auralic, Lumin devices etc. When one chooses a type with very good DAC implementation one can get rid of the external DAC. Less = more.
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