XLR + RCA question


#1

Apologies as surely this has been discussed earlier, but I haven’t been able to locate.

Incorporating a new pair of speakers (powered) for testing. Obviously keeping my amp and my main speakers for the dedicated room.
I was wondering if I could keep both connected at the same time? -namely XLR balanced to the amp AND main system, then 2RCA unbalanced to the new powered speakers.

Can that be done and actually have both work (i.e. be connected) at the same time or would I damage my DSjr?


#2

It is completely OK to do so.

The two outputs are in parallel. Specifically, the unbalanced output is in parallel with one-half of the balanced output. Thus, using both outputs at the same time unbalances the balanced outputs. This defeats the common mode noise rejection of the balanced outputs.

This does not hurt anything. It would matter only if common mode noise rejection is needed in your system.


#3

Thanks very much Elk!

That was the answer I was looking for exactly. I will be using a long pair of XLR’s then since it’d be basically going into a different room.

Cheers


#4

It will work without damaging anything physically. What I don’t know is what effect the extra capacitance from the RCA (SE) will be on just one leg of the now long XLR signal. The XLR has two signals, equal and opposite polarity. In theory, any noise from outside the cable induced onto the signal will result in the subtraction of the injected noise from the signal. When one of those legs has a capacitance different from the other leg (albeit at the source end of the circuit) I don’t know if the theory still holds to the same degree. There may be slight signal degradation. But it may be so small you don’t have to worry about it.

So plug it together as you describe and it’ll work fine. Then after everything burns in see if there’s any perceptible difference when you unplug the SE cables from the DS Jr. If you can’t hear any difference, leave 'em plugged in. If you do, then for those days when you want to do your critical listening then just unplug the SE cables at the DS Jr.

Just a thought.

–SSW


#5

Should be no problem. I would suggest testing the volume levels (at lower volumes) with each output “on,” and then both outputs “on” so you know what to expect volume output wise.


#6

What about power amp XLR+RCA inputs, is it okay to use XLR for DAC and RCA for AVR? When DAC is powered on then the AVR is off and vice versa only cables are connected.


#7

If I understand your question correctly, the XLR and RCA connectors are for the same input.

If so, no, you should not do this. Only one source should be connected to a single input at a time. This results in an impedance mismatch, may lead to a ground loop or other buzzes, and may cause damage.

More specifically, you would be paralleling the two sources. This lowers the impedance seen by the sources. This requires them to produce more current to drive the amp. The sound will likely suffer and you can possibly damage your equipment.


#8

Thanks for a quick reply Elk!

Both sources are grounded and not operating at the same time. I think the line outputs are switched off by the relays on the source side? (Mytek Brooklyn and Marantz AVR to M700) So input selector box is needed for switching between DAC and AVR to m700s?


#9

It does not matter if the sources are switched on or not, the connection is still there. It is the connection which creates the issue. (Similarly, you need not have your preamp or amp switched on for the source to see a load for break-in, such as breaking in a DAC.)

You need to add a switch to pick which source you want to use.

I also under stand PS Audio makes a really good preamp which would serve the purpose.


#10

I read this as different inputs. One set of XLRs output to an amp, and a seperate set of RCAs output to powered speakers in another room.