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Connect 2 separate amplifiers to DAC with 1 pair of Balanced Outputs

TheFrator

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I have a DAC (Schiit Bifrost 2) with one pair of XLR balanced outputs (L + R). I'm currently feeding my headphone amplifier with these balanced outputs. But I'm getting a Freya S preamp to use for the stereo I'm setting up and I want to feed it the signal from the Bifrost 2 too. Is it simple enough to get a XLR cable splitter like these?

https://www.amazon.com/gp/product/B07CKX36BN/ref=ox_sc_act_title_4?smid=A21TE5CLHZDYA7&psc=1

Or do I need something else?

Thanks for reading.
 

tonycollinet

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You should check output impdedance of the Bifrost, compared with the input impedance of the headphone amp and the preamp. As long as the input impedance of both devices in paralell is > 10x the output impedance, you should be fine.


EDIT : Bifrost output impedance is 75 ohm - you should be fine.
 
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TheFrator

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You should check output impdedance of the Bifrost, compared with the input impedance of the headphone amp and the preamp. As long as the input impedance of both devices in paralell is > 10x the output impedance, you should be fine.


EDIT : Bifrost output impedance is 75 ohm - you should be fine.
Thank you very much for answering. Do you have any suggestions for learning about why output impedance matters? Not disputing you or anything- I just like to learn :)
 

staticV3

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Thank you very much for answering. Do you have any suggestions for learning about why output impedance matters?
You want good voltage bridging to keep signal amplitudes stable and output devices happy.
For that you need low output impedance and high load impedance.
 
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tonycollinet

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Thank you very much for answering. Do you have any suggestions for learning about why output impedance matters? Not disputing you or anything- I just like to learn :)

Your interconnect circuit is output voltage-through output impedance-through input impedance (to ground) - to input circuit. It looks like this.
ioimpedance-I9oC4forBH8Vz6pcTK7TUiraENrIrc7U.gif


So your output impedance and input impedance are in series forming a potential divider. For example if Output R was equal to input R, the voltage seen by the input would be half the output voltage. The lower the input impedance with respect to the output impedance, the more of the output voltage you lose.

At the 1:10 ratio (actually 1:9) you'll only lose 10% of the output voltage.

Most output impedances are low (like the bifrost) and input are high - to avoid these problems.

If both input R and Output R are resistive then the problem is not to bad - you just get a reduced voltage and need more gain at the amp end to compensate.

However, if there is significant capacitance on the input compared with the output R, then you'll also get a change in frequency response causing a roll off in the high frequencies.
 
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TheFrator

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Your interconnect circuit is output voltage-through output impedance-through input impedance (to ground) - to input circuit. It looks like this.
ioimpedance-I9oC4forBH8Vz6pcTK7TUiraENrIrc7U.gif


So your output impedance and input impedance are in series forming a potential divider. For example if Output R was equal to input R, the voltage seen by the input would be half the output voltage. The lower the input impedance with respect to the output impedance, the more of the output voltage you lose.

At the 1:10 ratio (actually 1:9) you'll only lose 10% of the output voltage.

Most output impedances are low (like the bifrost) and input are high - to avoid these problems.

If both input R and Output R are resistive then the problem is not to bad - you just get a reduced voltage and need more gain at the amp end to compensate.

However, if there is significant capacitance on the input compared with the output R, then you'll also get a change in frequency response causing a roll off in the high frequencies.
1000 thank yous for typing this up and explaining. Got me thinking back to my physics days back in college.

The input impedance of my hp amp is 94 kOhms and the Freya S is 10 kOhms. So both these devices in parallel is far greater than 10x the 75 Ohm output impedence of the the Bifrost.
 

Rja4000

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I have a DAC (Schiit Bifrost 2) with one pair of XLR balanced outputs (L + R). I'm currently feeding my headphone amplifier with these balanced outputs. But I'm getting a Freya S preamp to use for the stereo I'm setting up and I want to feed it the signal from the Bifrost 2 too. Is it simple enough to get a XLR cable splitter like these?

https://www.amazon.com/gp/product/B07CKX36BN/ref=ox_sc_act_title_4?smid=A21TE5CLHZDYA7&psc=1

Or do I need something else?

Thanks for reading.
Except you'll need the opposite direction: 1 female to 2 males.

I personally use those:

Most important is the use of good connectors.
Cordial uses REAN connectors (Chinese company belonging to Neutrik), which are pretty good for the price.
 

tonycollinet

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1000 thank yous for typing this up and explaining. Got me thinking back to my physics days back in college.

The input impedance of my hp amp is 94 kOhms and the Freya S is 10 kOhms. So both these devices in parallel is far greater than 10x the 75 Ohm output impedence of the the Bifrost.
Correct. More like 121x :D
 
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TheFrator

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Except you'll need the opposite direction: 1 female to 2 males.

I personally use those:

Most important is the use of good connectors.
Cordial uses REAN connectors (Chinese company belonging to Neutrik), which are pretty good for the price.
Good call. Plus those look to be of higher build quality and not really that much more expensive.
 

Rja4000

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You want good voltage bridging to keep signal amplitudes stable and output devices happy.
For that you need low input impedance and high load impedance.
That reminds me of the biggest fiasco I've been involved in in terms of concert PA.

It was in the early 80s, a large audience (around 1000), and a rock band. A mixing console was installed as FOH, in the public area, and another desk as monitor mixer, on stage.
So each microphone was sent to both mixers, with kind of an Y cable.

The front of house mixer just didn't get any signal to work with, due to impedance problems.
That just didn't work.

At the time, analog mixers were often using a transformer at each input to unbalance signal.
The normal, professional, way of wiring for such a setup was to use transformer based splitters. But the organizers went on the cheap side, and that was forgotten. Or ignored.

The concert actually happened, but was mixed from only one desk, the monitor mixer, with all the problems one may imagine...
 

Rja4000

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Good call. Plus those look to be of higher build quality and not really that much more expensive.
I use them for measurements.
I have 8 of those plus 8 of the other gender (M-FF)
I continuously plug and unplug them, and never experienced any issue.
 
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