What is the better wiring for a DAC? Long USB cable vs. long unbalanced RCA?

[paulg1]

For example SMSL D6s DAC: The preamp is VTL 5.5 with unbalanced inputs. Computer for streaming needs a 25vft cable to connect. Should I place the DAC near the preamp with short RCA cables, and run a long USB-C cable, or place the DAC near the computer and run long RCA cable?

 

[DJNX]

Definitely RCA.
Certified USB-C cables, that can guarantee to function properly, will always be of short length. Whereas a decent RCA cable should be able to handle 25ft with no problem.
That being said, for length, always use ethernet, when possible.

 

[paulg1]

Thanks. That's good news. The DAC has Bluetooth, which would allow a wireless connection, but I use my speaker system with the TV as a monitor for movies often, and there is a time delay between the picture and the audio using that. A DAC with ethernet input would be nice, but they cost $$ like Okto 8 stereo with streaming option.

 

[sam_adams]

Use a balanced to unbalanced cable like the below:

The cable should be of the star-quad type, Mogami W2534 or similar. You'll pickup a few more dB of noise rejection over the length of the cable. If you want to go unbalanced, use a coaxial cable like Belden 8281F or Canare LV-77s.

 

[paulg1]

I considered using a balanced cable from the DAC to the preamp. There is a note in the Okto 8 Stereo DAC manual about this (quote below):

"We highly recommend using balanced cabling between analog audio components whenever possible. The main reason is that, due to the different reference, ground is not a part of the balanced signal path. This makes equalizing currents created by ground loops and electromagnetic interference, which would otherwise be injected into the signal, harmless. If you need to interface the dac8 with a legacy pre-amplifier or a power amplifier that has single-ended inputs only, there are three methods to do so:

1) A solid-state conversion circuit, for example the Neurochrome Universal Buffer
2) Audio transformers like Lundahl LL1584-3FXPHM
3) A special adapter cable with floating pin 3, like “Benchmark XLRF to RCA cable for analog audio with pin 3 floating”. The cable does not perform actual signal conversion; instead, it only uses one half of the balanced output from the dac8 without shorting the other half to ground. This method will result in a loss of performance, but it is recommended as a cost-effective way to connect subwoofers.

Warning: We strongly discourage the use of balanced-to-unbalanced cables and converters. Doing so will result in significantly decreased analog performance due to the short they present to the output of the dac8 Stereo's analog stage, potentially overloading it and risking damage after long-term use with high signal levels. Warranty does not apply to units with analog circuitry damaged by using XLR to RCA cables and converters."

Methods 1 and 2 are both quite costly.
Your solution is like their method 3; it suggests a loss in performance. Not sure how much. Their warning note scares me. Running 25 ft. of unbalanced cable, better or worse?

 

[Chrispy]

Why the long length needed in the first place?

 

[paulg1]

The seating position, with computer for streaming on a coffee table, is only about 15 ft away from the TV and speaker system, but the cables have to be run along two walls to be neat and avoid tripping hazard. A DAC with ethernet (DJNX alluded to this) would totally solve the problem. Which good, affordable DACs have Ethernet input?

 

[unpluggged]

The seating position, with computer for streaming on a coffee table, is only about 15 ft away from the TV and speaker system, but the cables have to be run along two walls to be neat and avoid tripping hazard. A DAC with ethernet (DJNX alluded to this) would totally solve the problem. Which good, affordable DACs have Ethernet input?

Just get a USB extender over twisted pair or an active USB cable.

 

[paulg1]

Thank you so much for suggesting this. The USB to ethernet extender solution is the way to go. Thunderbolt 4 compliant USB-C to ethernet connectors, along with a run of good ethernet cable (Cat 8) completes the job, with Thunderbolt 4 compliance, and inexpensive. A superb solution.

 

[unpluggged]

Thunderbolt 4 compliant USB-C to ethernet connectors, along with a run of good ethernet cable (Cat 8) completes the job, with Thunderbolt 4 compliance, and inexpensive. A superb solution.

Overkill for your current use, but fine for future-proofing

 

[voodooless]

Thank you so much for suggesting this. The USB to ethernet extender solution is the way to go. Thunderbolt 4 compliant USB-C to ethernet connectors, along with a run of good ethernet cable (Cat 8) completes the job, with Thunderbolt 4 compliance, and inexpensive. A superb solution.

What product can do this? Does it really support 40gbps over Ethernet ?

 

[Vincent Kars]

There are all kind of USB extenders.: https://www.thewelltemperedcomputer.com/HW/USB_Extender.htm
Check if they do support USB in High Speed as this is the mode needed for USB DAC's using UAC2.
https://www.corning.com/oem-solutio...active-optical-cables/usb-optical-cables.html might be an affordable solution.

 

[paulg1]

I checked on Amazon when Unplugged suggested this: These only cost $14 USD each. They say Cat 6 or better for ethernet cable,

Amazon.com

 

[Vincent Kars]

That is a adapter turning your USB-C into a Ethernet port.
This requires a USB host (PC, mobile).
I don't expect a slave (USB DAC) to recognize it.

 

[boxerfan88]

I run long usb (using 5M usb3 extender) from PC to SMSL DAC, and shorter XLR from DAC to speakers.

 

[paulg1]

My PC has USB- C output (actually thunderbolt 4). Can a pair of these function (with a good ethernet cable between them) to connect the PC to the DAC?

 

[GXAlan]

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[paulg1]

Looks like boxerfan88 has already implemented this. I would want to do the same, except with short RCA cables from the DAC to the preamp.

 

[voodooless]

My PC has USB- C output (actually thunderbolt 4). Can a pair of these function (with a good ethernet cable between them) to connect the PC to the DAC?

As @Vincent Kars already said, you cannot. It's just a USB to ethernet adapter. you cannot plug this into your DAC because it's not a USB host device.

Just get an optical USB cable, they are reliable and can bridge long lengths. Check out this topic for a similar question:

20 meter between PC <> DAC

Hi, how would you recommend connecting a PC with a DAC which is 20 meters away? AFAIK, I have two options: - active USB 2.0 cables - Toslink cables With both solutions I'm worried about if there is degradation in jitter and also bit-loss. Also, for the Toslink cable, I'd need to basically buy...

www.audiosciencereview.com

 

[paulg1]

This scheme won't work?