How do I connect my sound card to a headphone amp?

[Heyyoudvd]

I recently ordered my first headphone amp because I bought my first pair of headphones that could really benefit from an amp (HD6XX + Topping L30), and rather than spend more on an external DAC, I figured I’d use my PC as the DAC, as I‘ve already got a pretty good sound card (Xonar DX).

I’m not really sure how to connect the Xonar to the L30 for two reasons:

1. Which output jack do I use? You can see the specs here. There are five 3.5 mm jacks on the card, where #2, 3, 4, and 5 are for front, center, side, and rear speakers in a 7.1 system (I have three of those four hooked up, as I have a 5.1 PC speaker system.) The jacks run to the woofer/amp, which then runs to each speaker. But then there’s output #1, which is a combination line-in and S/PDIF out, and it comes with a little adapter to hook up an optical cable. So if I’m hooking up the headphone amp, do I want to hook it up to #1 via that S/PDIF and optical cable, or do I want to use a regular 3.5mm to RCA, and go from #2 to my amp? For reference, that #2 (front-out) has an SNR of 116dB.

2. If I’m going via that front-out rather than the line-out (aka. output #2 rather than #1), does it matter what kind of 3.5mm to RCA cable I use? Would cheaper ones degrade the quality? The reason I’m asking is that I found an old 3.5mm to RCA cable lying around from a crappy digital camera I bought 10+ years ago. Would that suffice or is there some quality threshold I should look out for with 3.5mm to RCA cables?


Thanks in advance.

 

[Roseval]

#1 via that S/PDIF and optical cable

No, that is digital and the L30 don't have a DAC

Use your #2 assuming this the same as the front out in 5.3.1 of the manual.
If you have a cable already, use it.
If not broken, oxidized , etc, it won't degrade the sound.
Likewise a new one won't improve the sound either.

 

[Heyyoudvd]

No, that is digital and the L30 don't have a DAC

Use your #2 assuming this the same as the front out in 5.3.1 of the manual.
If you have a cable already, use it.
If not broken, oxidized , etc, it won't degrade the sound.
Likewise a new one won't improve the sound either.

Ah, for some reason I was under the impression that a line-out uses the DAC but bypasses the amp. If it bypasses both and just provides a straight-out digital signal, doesn’t that mean the sound card is essentially doing nothing?

Yeah, my current setup is sort of like 5.3.1 in the manual, except each cable terminates in the woofer as a 3.5 rather than RCA. With the new setup, I’ll have the headphone amp in between #2 and the woofer, so it’ll be 3.5 to RCA into the L30, and then the L30’s preamp will go RCA to 3.5 into the woofer.

I think that makes sense, although it will mean that the L30 volume knob will only control 2 channels of the 5.1 speakers, so I’m not sure how that works.

Regarding the cable, that’s good to hear. What about using multiple connectors? For example, I don’t have a 3.5 to RCA male cable, but I do have a 3.5 to RCA female adapter, and then a male RCA to male RCA cable. Is there any issue with stacking multiple cables/connectors like that, or is that fine in terms of sound quality?


Thanks.

 

[skyn3t]

just connect the headphone amplifier to the "line 1" jack on the sound card and in the control panel set output to "2 Speaker".
This will give you 2.0 stereo output to the headphones amplifier.

 

[PurpleAngel]

The Xonar DX's Front Speaker/Headphone jack, is more like a line-output (like for connecting to amplifiers), that just also pretends to also act like a headphone jack (impedance issue).
So my two cents.
Disable the motherboard's onboard audio, in the BIOS.
Install the Unified Xonar Drivers.
Connect the DX's Front speaker jack (3.5mm) to the line-inputs (RCA) jacks on the L30.
I usually try Monoprice for cables.

 

[Heyyoudvd]

just connect the headphone amplifier to the "line 1" jack on the sound card and in the control panel set output to "2 Speaker".
This will give you 2.0 stereo output to the headphones amplifier.

To confirm, by Line 1, you mean the output for the L/R front speakers, not the main line-out jack that I mentioned, right?

Also, is there any way to retain output to my other speaker channels? I don’t use the rear speakers anymore, but would it be possible to maintain a sort of 3.1 system (ie. the front L/R as well as 3.5mm output for the sub and center). If the L30 preamp basically sits between the Xonar Line 1 and the front speakers, what happens with the Xonar Line 3 (center), which will bypass the L30?

And finally, the Xonar has a setting specifically called Headphone. Should I use the 2 Speakers setting rather than that? There’s also an “FP Headphone” setting, but that routes audio to the headphone jack on the front of my PC tower, and that adds A LOT of noise for some reason.

Thanks.

The Xonar DX's Front Speaker/Headphone jack, is more like a line-output (like for connecting to amplifiers), that just also pretends to also act like a headphone jack (impedance issue).
So my two cents.
Disable the motherboard's onboard audio, in the BIOS.
Install the Unified Xonar Drivers.
Connect the DX's Front speaker jack (3.5mm) to the line-inputs (RCA) jacks on the L30.
I usually try Monoprice for cables.

I’m curious, does the motherboard’s audio affect the sound card? Can the noise from the motherboard affect the Xonar’s output? I hadn’t heard that before.

 

[skyn3t]

To confirm, by Line 1, you mean the output for the L/R front speakers, not the main line-out jack that I mentioned, right?

Yes Sir.

Also, is there any way to retain output to my other speaker channels? I don’t use the rear speakers anymore, but would it be possible to maintain a sort of 3.1 system (ie. the front L/R as well as 3.5mm output for the sub and center). If the L30 preamp basically sits between the Xonar Line 1 and the front speakers, what happens with the Xonar Line 3 (center), which will bypass the L30?


And finally, the Xonar has a setting specifically called Headphone. Should I use the 2 Speakers setting rather than that? There’s also an “FP Headphone” setting, but that routes audio to the headphone jack on the front of my PC tower, and that adds A LOT of noise for some reason.

Thanks.



I’m curious, does the motherboard’s audio affect the sound card? Can the noise from the motherboard affect the Xonar’s output? I hadn’t heard that before.

A: Yes Sir.

B: If you have monitor speakers ( or in general 2.1 setup ) you can hook up into the amp and disconnect the headphone when you want you speakers on.

 

[PurpleAngel]

I’m curious, does the motherboard’s audio affect the sound card? Can the noise from the motherboard affect the Xonar’s output? I hadn’t heard that before.

Normally the onboard does not effect an add-on sound card, I just like to disable the onboard audio, more for peace of mind.