Digital Coax 1.5m

[devianet]

Worth bearing in mind that the companion has the ability to output a mono (downmixed from stereo) subwoofer output. This is exactly how I have my 440 configured, to drive my REL at line level.

This can only mean that the digital link between the two units is stereo. So, in my configuration, the master takes the R signal and uses it for both amp channels in that box (left amp channel inverted). It then sends both R and L to the companion. The companion takes the L signal and uses for both amp channels in that box (left amp channel inverted). Then it also takes the L + R signals and mixes them to mono for the subwoofer output.

[ada]

Which is fine but still it doesn’t change the reality of one of your amps are not subject to the signal that passes through the link cable. By the nature link cable’s sound quality only impacts the sound that the amp gets the input from the link.

[devianet]

I did not claim that it did. My description of the signal path supports the point of view that the speaker driven by the master is not affected by the details of the interconnect joining the master and companion. The speaker driven by the companion, however, could - at least theoretically - be affected. It just so happens that I don't hear it, but then I might have broken ears.

There's also the complicating detail that the inputs on the companion can be used, and, in this case, the whole signal path has to be reversed, including the direction of the interconnect. Unless anybody can think of any other way it could possibly have been implemented? That wouldn't need the interconnect to work in both directions simultaneously? In this case it's the speaker driven by the master that could - at least theoretically - be affected by interconnect details.

[daniel.avasilichioaei]

Regardless of the direction of the signal, it is a digital signal, and it reaches intact from one amplifier to another. From this point of view, the cable cannot influence the sound quality.
The hypothesis remains that the Devialet is a very poorly designed and/or built amplifier and additional currents (not the digital signal) flow through the cable from one amplifier to another and they end up affecting the sound quality. I don't believe in this hypothesis, but others may...

[hardcore]

The interconnect cable affects the sound of both master and companion, but it's not because of differences in the data signal itself.

It's because the interconnect cable creates a ground loop between the amplifiers, which introduces noise in the ground plane of both the Devialets. This is likely why many of us prefer using the RCA->XLR connection because the XLR input has transformer isolation on the signal pins, which may reduce the effect of the ground loop.

https://www.circuitbread.com/ee-faq/what...round-loop

Also, daniel is right that the interconnect signal is the stereo music signal, plus control signals (volume, input, etc.). Another member of this forum used an ifi spdif ipurifier on the interconnect link, and it works.

[ada]

First of all, I don't think there is a difference in 75 ohm digital cables in the 1.5 meter range. But if there is, the sound difference is not only due to the background noise, but also the impact of the medium, which is the cable itself. If someone says that one cable makes a difference to another, I assume that he doesn't pay 10 times more just to have the background noise distributed better between the amplifiers, but rather he expects better connectivity. If that's not the case, you don't need to read the rest

Secondly, yes, the signal is 100% stereo, but not bi-directional. It's just one direction from the one with the input to the one without. (I don't say master or slave because the input could be on the slave).

What we are discussing here is;

1. The signal comes from the source to the head unit
2. The head unit converts the signal into a low-level PCM signal that will be ready to be sent to the DACs
3. The head unit receives the signal directly from the internal components
4. The second unit receives the signal from the link cable!
5. The music is played in dual mono mode

In this setup, the difference in the medium (cable) only affects the sound heard on the second unit. Yes, the background noise is bi-directional, but we are not just talking about noise, but about the cable making a difference to the digital signal and that only applies to the sound from the second amplifier.

[hardcore]

A ground loops goes across both amplifiers via the link cable and affects the ground plane noise on the circuits of the clocks and DACs on both amps.

I avoid using the trigger cable as well, as it also adds another ground loop path.

It's not just Devialets that are sensitive to ground plane noise. Digital devices like DACs and clocks are very sensitive to noise on the ground plane and taking effort to remove or reduce ground loops can significantly improve the sound quality.

[markush]

I use both 220 Pro on an AudioQuest Niagara 5000 avoiding ground loops when connected for the dual mono setup.
Apart from that if you have another power setup it might be interesting to use a iFi iPurifier SPDIF along with a Project Accu Box to get complete isolation! https://www.project-audio.com/en/product...ox-s2-usb/