Using both the XLR and RCA outputs on a DS Sr


#1

We have two amplification systems in a central vented and cooled closet in our home. One Home Theater Denon for surround/multi-room and a BHK Preamp/Krell for the Stereo L/R. Previously had gold RCA splitters for the DAC outputs and since recieving the BHK Pre ran XLR’s from the DAC to the Pre and removed the gold RCA splitters.

Do we risk damaging the DS DAC Sr outputs using both XLR and RCA outputs?

If so what is the best approach to provide both an XLR and RCA output from the DAC? A modified cable having both RCA and XLR amp input connections from an XLR output connection at the DAC?

Thanks RR


Using two outputs on a DirectStream DAC
#2

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.


DS Sr. connecting direct to a sub?
#3

Thanks ELK


#4

The Directstream Senior and Junior manals give conflicting advice on these connections.
The Senior manual advises against using both XLR and coax together, whereas the Junior manual says it is OK to do so.

Is the sound quality compromised by using both connections to feed different amplifiers, even if only one of those amps is on at any one time?


#5

I only know the specifics of the DS Sr. I am unsure as to how Jr. is wired.

The sound is not compromised in any way. The only issue is the balanced connection is no longer balanced, compromising common mode noise rejection. Most people are not going to have any issue with this noise in any event.

It does not matter if the amp is on or off. It is the connection which matters. The amp is providing a sink for the signal.


#6

Elk is correct. FWIW The DS Jr uses a fully differential opamp for it’s output. These opamps are designed to emulate a transformer so there’s no effective difference between the Jr and Sr’s output with regard to this issue.


#7

So why are the two manuals giving different advice? It confused me.


#8

I suspect Paul was thinking that the DS Jr’s opamp based output was done with two typical audio opamps and the one that had a slightly bigger load would provide a little more current. But differential opamps are designed to emulate a transformer (there’s no ground on the output), so the same rules apply to it as if a transformer were used.
In any case it’s nothing to worry about possibly except if your system has more than usual common mode noise (e.g. a 60 cycle hum.)


#9

I can only speculate, but both are correct. It is perfectly OK to do so, but ill-advised if you desire to keep the balanced connection balanced.

Bottom line: Do whatever works for you. :slight_smile:

Edit: Ted beat me. I like his theory.


#10

Thanks Ted. I’m reassured.


#11

Just want to make sure I’m understanding this all…

My primary system uses a balanced/xlr connection from DSD (out) to amp. I also have an Echo dot I connect to the RCA inputs of the DAC. Of course, when I’m using the echo dot, I’m not using the device that uses the USB input (or the bridge ii which will likely soon replace usb as my “main” input).

In this scenario, I don’t think I’m affecting the balanced outputs, or am I? thanks!


#12

No, you are not affecting the balanced outputs by connecting a single-ended input.