[thatguyyoulove]

I am thinking about getting the Xonar ST (and H6 daughter board) to connect to my external home theater amplifier (Emotiva UPA-5), speakers, and Grado SR80s (connected directly to the XT not the amplifier as it has no headphone jack). I keep reading however that there is a mechanical relay that makes a "pop" or "click" when switching audio sources between analog out and headphone out as apparently it won't do both simultaneously. 

 
Does anyone know how bad this pop is and if it will damage my home theater speakers or my headphones if the volume is up? I switch between headphones and speakers multiple times a day depending on who is studying nearby, what I am listening too, or how late it is.

 

[audionewbieyao]

No, the click of the relay is meant to protect your speakers and amp by avoiding the poping sound during start up or turn off, so don't worry and just go for it.

 

[thuantran]

To add to it, the click is on the card not at your speakers or headphone. It's scary when you first hear it though.

 

[audionewbieyao]

Well... if you have AVRs from YAMAHA or Denon etc, when changing the AV source, you'll hear the same thing too.
So it's the same thing, just no company before Asus has adopted this solution to protect your gears.
 
Creative and others just don't care about the potential damage of poping sounds to your speakers I guess.

 

[sonci]

 
Quote:

Well... if you have AVRs from YAMAHA or Denon etc, when changing the AV source, you'll hear the same thing too.
So it's the same thing, just no company before Asus has adopted this solution to protect your gears.
 
Creative and others just don't care about the potential damage of poping sounds to your speakers I guess.

They`re called mutting transistors, usually they prevent clicking during pc startup,
you can find them on every old Creative cards, or others, at the time when Asus used to build pci bridges..
 
In fact you can a hear a click on the EMU1212M(Creative btw) during sample rate convertion,
and that`s a pretty old card..

 

[germanium]

The popping noise you hear in the speakers / headphones when switching back & forth to & from the headphone amp is likely the collapse & charging of the magnetic field in the relay on the soundcard. This magnetic field is in very close proximity to the signal lines & are before the last stage of amplification so when it charges or collapses introduces a spike into the signal lines. It is not enough to damage anything so don't worry about it.
 
If you were to hear this noise with muting transistors it of somewhat more concern as that would mean there is some D.C. offset present & should be measured to make sure it is safe level of D.C. offset but solinoids will make this noise regardless of D.C. offset level & on this card the D.C. offset is quite low.

 

[sonci]

Yes, mutting transistors prevent the clicking, don't click, unfortunately since in the sound chain they somehow degrade sq.

 

[germanium]

Forgot one thing, The signal lines that are being switched do have D.C. on them but that D.C. gets cancelled in the output of the buffer or headphone amp. That D.C. offset level is about + 2.5 volts. This voltage goes into both the + & - inputs of the buffer or headphone amp. While the D.C. is cancelled at the output of these amps  the sudden application  of D.C. this strong at the amps input is actually the most likely cause of the popping noise at the speakers or headphones when switched as it takes a moment for the amp to stabilize once the signal is switched. Again this popping is not dangerous to your equipment.
 
The pop you will hear is quite loud however if your volume is turned up on your speakers & will be loud regardless of volume from the internal headphone amp.

 

[ceilihirlg]

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The popping noise you hear in the speakers / headphones when switching back & forth to & from the headphone amp is likely the collapse & charging of the magnetic field in the relay on the soundcard. This magnetic field is in very close proximity to the signal lines & are before the last stage of amplification so when it charges or collapses introduces a spike into the signal lines. It is not enough to damage anything so don't worry about it.
 
If you were to hear this noise with muting transistors it of somewhat more concern as that would mean there is some D.C. offset present & should be measured to make sure it is safe level of D.C. offset but solinoids will make this noise regardless of D.C. offset level & on this card the D.C. offset is quite low.

Nice writing, Now I got it, Thanks for your explanation!