[powerhouse]

It seems most sound cards now come with an amp'ed headphone jack, is there a way to disable the onboard amp so I don't damage my external headphone amp? I would like to use my desktop speakers and headphones without have to plug/unplug anything so the line out will already be used. What sound cards should I buy to do this?
 
 

 

[stv014]

It is an exaggeration that most cards have a headphone amplifier. Only a few have one that is powerful enough to exceed the 2 Vrms line level, and those that do (e.g. the Xonar ST/STX) have separate line and headphone outputs. Most often the combined line/headphone output jack is just line level with some buffering to make it more or less usable with headphone loads.
 

 

[powerhouse]

Right. but I need to have a separate line and headphone output to listen to my speakers and headphones, and those that have that feature all seem to be amped. I read that the STX has impedance settings, according to this site http://www.stereophile.com/content/asus-xonar-essence-ststx-soundcards-measurements I can set the headphone output to 885mV, would that make it safe for my amp?
 
Thanks, 
 

 

[stv014]

The line (RCA) output of the ST/STX is not amplified, it has a fixed output level of 2 Vrms, which is the standard for CD players. The headphone output is separate, and the "impedance" setting only affects the level of that.
 

 

[powerhouse]

I don't think I'm explaining myself well enough or I'm misunderstanding something. I want to have both my speakers and headphones connected to the sound card at the same time, so my line out would already be used for my speakers. Don't I need two line out's (1 RCA/1 headphone) to do this?
 
Thanks,

 

[stv014]

Quote:

Don't I need two line out's (1 RCA/1 headphone) to do this?

 
That is exactly what the ST/STX have. RCA connectors for the line output, and a separate 1/4" headphone jack. However, I think it only outputs a signal to one of these at a time, and you can select in the mixer which one (i.e. if you choose "2 speakers", then line level signal is sent to the RCAs, and "headphones" will output amplified audio to the 1/4" jack).

 

[PurpleAngel]

The Essence STX has a Front port speaker setting in the analog out "FP 2 Speaker".
Do you have the front headphone jacks port on the front of your computer case hooked up to the Essence STX?
So you can try a cable with a mini stereo jack (1/8" 3.5mm) on one end and at the other end use whatever your external headphone amplifier uses (RCAs?).
Then you just next do the switching in the control panel.

 

[germanium]

All front port output options use the headphone amp. For the most part that is ok except if you want to hook to a D.C. coupled amp with a relatively high gain as the headphone amp has between 15 to 19mv D.C. output & a D.C. coupled amp will amplify this voltage by whatever it's gain factor is. This could cause these kind of amps to overheat if it's gain is high enough.

 

[stv014]

It is generally best to avoid using the front panel jacks if possible. Other than cable related problems (too short headphone cord, not having any RCA to RCA cable, etc.), the only reason why you would want to use it is with onboard audio that outputs an amplified signal only to the front panel. The grounding of the front panels is often poorly designed, resulting in high noise and interference without modding.
 

 

[PurpleAngel]

Quote:

It seems most sound cards now come with an amp'ed headphone jack, is there a way to disable the onboard amp so I don't damage my external headphone amp? I would like to use my desktop speakers and headphones without have to plug/unplug anything so the line out will already be used. What sound cards should I buy to do this?

You could always get a Fiio D3 or D5 DAC, connect your speakers or headphone amp. that way.
 
 
 

 

[ROBSCIX]

Why not use the RCA outputs on the card?  They are the highest quality output on that card according to the measurements and specifications.
 
To note, the STX/STX, can only use one output at a time, either the line outputs or the headphone output. 

 

[PurpleAngel]

Quote:

Why not use the RCA outputs on the card?  They are the highest quality output on that card according to the measurements and specifications.
To note, the STX/STX, can only use one output at a time, either the line outputs or the headphone output. 

I think he wants to have both his speakers and his external headphone amplifier hooked up to the STX's RCA jacks.
So he keeps having to switch back and forth with the RCA cables.
Or someway to have both his speakers and his external headphone amplifier hooked up to the STX at the same time, without using an amplified port.
 
 
 

 

[stv014]

Good point, I missed the external amplifier. The ST/STX are perhaps not the best option then (in the sense that the amplification feature is wasted), unless the built-in amplifier is actually not worse than what the OP already has, so the card can be used as intended. Are there cards that output the same audio to more than one line output ? I know that with the Xonar D1 (and therefore probably also DX, D2, and D2X) it is possible to upmix a stereo signal to multiple outputs with separate volume controls, at least under Linux. If nothing better is available, using a single line output and a simple splitter may also be an option.
 

 

[ROBSCIX]

 
Quote:

I think he wants to have both his speakers and his external headphone amplifier hooked up to the STX's RCA jacks.
So he keeps having to switch back and forth with the RCA cables.
Or someway to have both his speakers and his external headphone amplifier hooked up to the STX at the same time, without using an amplified port.
 
 
 

In that case, if he wants to connect multiple devices to the RCA outputs he will need to use either splitters, or a switch.