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question regarding electrical noise, network cables, optical

sonder

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I'm having a little bit of trouble squaring away different schools of thought regarding connecting devices.

Disregarding higher hi-res audio and potential benefits it brings, and sticking strictly to 96/24 or lower for discussion:

Why would network cables to streamers and then USB to DAC, both of which carry electrical current from (often poorly designed) switching power based components be /better/ than wifi + optical?

If my home mesh network is strong and there's no data loss or interference for such a comparatively low stream of data compared to other uses, and then said device is connected via optical to DAC, thus just light based, is this not potentially the "cleanest" signal I can get here?

For example:
- a tiny 5v/1amp chromecast audio over wifi, then optical to dac
- the same device via the network adapter plug with internal network interface and network cable through to average switching gear, then optical to dac
- a larger streaming device with more electrical things going on through network cable to same network, then usb to dac

My "gut" tells me that less wires carrying electrical current and nuances the cleaner the signal in to the dac will be, this is why people use fibre optical cables and high grade switches isn't it, and devices to clean up signals over usb wires, to get rid of that, why would I introduce it?

Can anybody shed any further light here?
 

HarmonicTHD

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I'm having a little bit of trouble squaring away different schools of thought regarding connecting devices.

Disregarding higher hi-res audio and potential benefits it brings, and sticking strictly to 96/24 or lower for discussion:

Why would network cables to streamers and then USB to DAC, both of which carry electrical current from (often poorly designed) switching power based components be /better/ than wifi + optical?

If my home mesh network is strong and there's no data loss or interference for such a comparatively low stream of data compared to other uses, and then said device is connected via optical to DAC, thus just light based, is this not potentially the "cleanest" signal I can get here?

For example:
- a tiny 5v/1amp chromecast audio over wifi, then optical to dac
- the same device via the network adapter plug with internal network interface and network cable through to average switching gear, then optical to dac
- a larger streaming device with more electrical things going on through network cable to same network, then usb to dac

My "gut" tells me that less wires carrying electrical current and nuances the cleaner the signal in to the dac will be, this is why people use fibre optical cables and high grade switches isn't it, and devices to clean up signals over usb wires, to get rid of that, why would I introduce it?

Can anybody shed any further light here?
Where did you get the information that it would matter?

As long as either connection is stable you get no degradation or improvement in sound regardless of your three possibilities.
 

twsecrest

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Modern USB offers better audio packet control, over optical/coaxial.
I would also assume a network cable, offers better packet control, over optical.
(Both offer controlled two way communication).
S/PDIF optical/coaxial just spits out audio data packets and has no idea if it arrived safety at the other end (only one way communication).
 
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sonder

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optical just spits out audio data packets and has no idea if it arrived safety at the other end

Why would an optical cable have packet loss though, presuming it hasn't been hit with a hammer or broken strands or a massive forced bend in the thing. We're dealing with centimeters here, not kms.

Where did you get the information that it would matter?
It seems to matter everywhere, or I'm mislead by the presence of devices and chips to reduce interference from electrical sources, perhaps wrongly I was working under the assumption that reducing noise and getting the cleanest possible signal from source to speakers is an optimal setup.
 
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wwenze

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Why wouldn't an optical cable have packet loss? It also runs on electronics and receive the signal from electronics. The LED intensity also has slew rate and there is reflection and attenuation in the optic fibre.

My "gut" tells me that less wires carrying electrical current and nuances the cleaner the signal in to the dac will be, this is why people use fibre optical cables and high grade switches isn't it, and devices to clean up signals over usb wires, to get rid of that, why would I introduce it?

The problem is once you really dig deep, you will realize that a cable is really just a waveguide for electromagnetic wave, just like air is also a conductor of electromagnetic waves. The optic fibre is also a waveguide but it works for waves that are of a much higher carrier frequency.

And certainly from an internet standpoint the wireless connection is way inferior compared to a wired connection.

The main concern is common-mode noise but that is not a problem for ethernet since the ethernet standard requires isolation transformers. Heck, the wireless signal (which is technically common-mode by nature) will be more noisy since either the signal or the noise generated by the receiver circuit can go anywhere, with BT receivers often being the best teaching example. In contrast the signal in cables are confined in the cable.
 

HarmonicTHD

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Why would an optical cable have packet loss though, presuming it hasn't been hit with a hammer or broken strands or a massive forced bend in the thing. We're dealing with centimeters here, not kms.


It seems to matter everywhere, or I'm mislead by the presence of devices and chips to reduce interference from electrical sources, perhaps wrongly I was working under the assumption that reducing noise and getting the cleanest possible signal from source to speakers is an optimal setup.
You are misled. See the many reviews of such devices / cables here and the proof that there is no effect on sound quality. Manufacturers are out for your money and have a vested interest to continue spreading false information. Pick a connection of your convenience eg USB and be done.

But if you can be specific where exactly you got the information one could have a closer look as opposed to discuss generalizations.
 
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sonder

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And certainly from an internet standpoint the wireless connection is way inferior compared to a wired connection.

Minor point here, in my own particular setup I have the entire house cabled through the wall, but also have a good mesh network with wireless 8x routers meshed, and ability to network cable in to them too. I tend to lean to cables for the most persistent connections, e.g. if I have ssh terminals open for days/weeks on end. As far as streaming goes, I haven't noticed any difference regardless of connection types, so for ease I'm sticking to chromecast audio via wifi -> optical ->dac and also w/ usb in to dac from pc. No discernible difference, which I expect will stick, or perhaps as I upgrade amps/speakers I'll notice more.

Thanks both for the replies, appreciated.
 

twsecrest

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Why would an optical cable have packet loss though, presuming it hasn't been hit with a hammer or broken strands or a massive forced bend in the thing. We're dealing with centimeters here, not kms.


It seems to matter everywhere, or I'm mislead by the presence of devices and chips to reduce interference from electrical sources, perhaps wrongly I was working under the assumption that reducing noise and getting the cleanest possible signal from source to speakers is an optimal setup.
Modern USB gives the receiving device (USB DAC?) control over the timing of request for the info (audio data packets) and allows the receiving device to get the data packets at a controlled rate the receiving device can handle.
S/PDIF optical/coaxial sends the packets, but it may not be in a way the receiving device can effectively 100% handle.
 

MaxwellsEq

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Why wouldn't an optical cable have packet loss? It also runs on electronics and receive the signal from electronics. The LED intensity also has slew rate and there is reflection and attenuation in the optic fibre.
I designed and project-managed a multi-mile dark-fiber (passive) optical network resiliently serving many sites, with hundreds of fibers in each duct and capable of multiples of Tbits/s. It's been in the ground for more then 20 years. There is still no packet loss due to fibers ageing. Over this period much of the electronic kit has been upgraded several times, so transmitters and receivers have been replaced (usually with a ten-fold or hundred-fold enhancement. Fiber is extremely robust and reliable.

When transmitters and/or receivers degrade, bit-error rates creep up or data just stops. But, this is easily detectable by increased dropped higher-layer Ethernet or IP checksums. A 1% bit corruption can create a 50% checksum packet drop, so minor degradation is immediately obvious.
 

Zapper

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One potential disadvantage of wired connections is hum and noise from ground loop problems, where the system is grounded at multiple points and ac voltage is developed between them from ambient electromagnetic fields from 50/60 Hz domestic power, nearby high power RF transmitters, etc. A wireless or optical connection breaks ground loops. So your example of a Chromecast or WiiM into a DAC via Toslink avoids those potential problems. That's how I do it. It also eliminates a source of component failure if lightning strikes nearby and the induced voltages in the ground loops can reach thousands of volts. Industrial electronics makes extensive use of galvanic isolation to prevent such failures, and optical and wireless links are forms of galvanic isolation.

The only downsides I know have to do with transmission problems. A weak Wifi signal can result in dropouts and/or a reduction in bitrate in Spotify for example. A defective Toslink cable can result in audible degradation. But these problems are easily solved.
 

Zapper

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Modern USB gives the receiving device (USB DAC?) control over the timing of request for the info (audio data packets) and allows the receiving device to get the data packets at a controlled rate the receiving device can handle.
S/PDIF optical/coaxial sends the packets, but it may not be in a way the receiving device can effectively 100% handle.
True. One disadvantage of SPDIF (either optical or coax) is the clock is transmitted with the data and requires a clock recovery PLL. The resultant clock can have jitter from both the original source and the clock recovery circuit, and jitter causes a reduction in the SNR of the signal. A good DAC will reclock the data after the receiver to a very stable PLL, but not all of them do so. As you mentioned, the receiving USB device can use its own stable clock and receive and reclock packets at its own rate, avoiding one source of jitter. Of course that can be screwed up too.
 
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