Backwards RCA Y-splitter for 2 digital coax sources?

[tmtomh]

This might sound crazy, which I guess is why I'm asking.

In another thread (which I can't remember or find at the moment), folks were discussing the lack of inexpensive digital audio switches on the market: there are a good number of inexpensive digital format converters, and even one or two converters with multiple output formats (like the Schiit Eitr). But there are virtually no sub-$500 (let alone simple sub-$200) digital format converters with multiple INPUTS.

So some folks were saying that if you're using digital coax, then a simple passive analogue RCA switchbox should work fine, as long as it's decently constructed.

Taking that a step further, I was wondering, why do you even need a switch? If you have two source devices with digital coax outputs, why not just connect them to an RCA y-splitter, using the two RCA "outputs" as the inputs and the single RCA "input" as the output? Of course it would be a hot mess if you played a signal from both devices at the same time.

But if you didn't, wouldn't the splitter just pass along the digital signal from whichever device was playing?

That would eliminate the need for a remote control for the switcher, or for getting up and manually flipping a switch.

I understand that in certain situations having two devices connected at the same time can create issues even if only one is active, but in this kind of a situation I would imagine that would not be a problem.

What do folks think?

 

[staticV3]

When you play from one of the two Coax sources, it would have both the Coax sink, and parallel to that, the second inactive Coax source loading down its output. Something to consider.

The active source needs to be able to tolerate the higher load and the passive source needs to be able to tolerate having its output driven by the active source.

Also, the Coax splitter should ideally preserve the 75Ω characteristic impedance.

 

[tmtomh]

When you play from one of the two Coax sources, it would have both the Coax sink and parallel to that the second inactive Coax source loading down its output. Something to consider.

Also, the Coax splitter should ideally preserve the 75Ω characteristic impedance.

Ah, I see - thanks! Would this load/potential degradation be similar to how a coax connection’s impedance gets more important with length? In other words, would the combined length of both coax connections (plus the length of the single run coming out of the splitter) be an approximate guide for whether it would work, just like we often say that an analogue RCA cable is probably fine for digital use as long as the run is short?

 

[Chrispy]

Well, not something I've needed and not sure would have considered if I did, but wondering how this works....the old wye not wye probably doesn't apply tho

 

[staticV3]

Ah, I see - thanks! Would this load/potential degradation be similar to how a coax connection’s impedance gets more important with length? In other words, would the combined length of both coax connections (plus the length of the single run coming out of the splitter) be an approximate guide for whether it would work, just like we often say that an analogue RCA cable is probably fine for digital use as long as the run is short?

I think that both load characteristics and total effective characteristic impedance should be examined independently and only if both are confirmed good, should you use this method.

Otherwise, a Cooidea Toslink Switch is the safer bet.

 

[john61ct]

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[Redacted]

Just remember, the use of co-ax is just using convenient, cheap, readily available cabling and connectors (usually RCA for audio applications).
That co-ax is massively over-specified for use in audio. With the signal strengths and cable distances you probably need to connect some of your digital audio units, you don't need to worry too much about things like termination impedance and characteristic impedance of the cable. I'd be surprised if a £20 RCA switch with a remote didn't work fine. Bear in mind, many models are able to carry video signals too, which is a much higher bandwidth signal. If it were me, I'd buy one from say Amazon, and if it did not work in your application, return it for refund. That Cooidea Toslink Switch is also good value for optical hookups (which I'd use over co-ax, as it's easier to route or hide at the back of units).

 

[somebodyelse]

This one has been recommended here a few times, with both coax and toslink inputs and outputs.
https://www.tindie.com/products/beni_skate/automatic-spdif-opticalrca-audio-switch/

Composite video switches would be an option if you only want coax, but they're disappearing as security cameras have mostly moved to digital. A lot of them have BNC rather than RCA.

 

[sergeauckland]

This might sound crazy, which I guess is why I'm asking.

In another thread (which I can't remember or find at the moment), folks were discussing the lack of inexpensive digital audio switches on the market: there are a good number of inexpensive digital format converters, and even one or two converters with multiple output formats (like the Schiit Eitr). But there are virtually no sub-$500 (let alone simple sub-$200) digital format converters with multiple INPUTS.

So some folks were saying that if you're using digital coax, then a simple passive analogue RCA switchbox should work fine, as long as it's decently constructed.

Taking that a step further, I was wondering, why do you even need a switch? If you have two source devices with digital coax outputs, why not just connect them to an RCA y-splitter, using the two RCA "outputs" as the inputs and the single RCA "input" as the output? Of course it would be a hot mess if you played a signal from both devices at the same time.

But if you didn't, wouldn't the splitter just pass along the digital signal from whichever device was playing?

That would eliminate the need for a remote control for the switcher, or for getting up and manually flipping a switch.

I understand that in certain situations having two devices connected at the same time can create issues even if only one is active, but in this kind of a situation I would imagine that would not be a problem.

What do folks think?

That might work provided that the unused source was switched off, or completely shut down. Some sources still send a stream with digital silence on it when there's no audio playing. That would indeed royally screw up the stream for the wanted source.

The might above refers to the comments also made above by others that the inactive source, even if switched off will load the wanted output, so the receiver might not lock, or not reliably. Considering that no damage will be done to either sources or receiver, and the cost is trivial, just try it, it might work fine.

I wouldn't worry about impedance matching if you're dealing with short cables, say under 5m.

S.