[Airwolf]

I am currently using a Sound Blaster Recon 3D Fatal1ty Professional card outputting via the amplified headphone jack to a Schiit Adgard 2 amplifier.  I have a set of HiFiMAN HE-400 headphones with focus pads connected to the Asgard 2.  I would say I spend about 80% of my time on my PC playing games (TF2, Payday 2, Battlefield 4, or some other FPS du jour) and the other 20% divided between watching movies/TV shows and listening to chill trance and chill-step.  I am a little worried that outputting an amplified signal to my Asgard 2 is giving me a less than optimal auditory experience.
 
If my sound card is a weak link, is there a sound card better suited to my setup that perhaps has non-amplified outputs, but is still great for gaming?  Would I be better off with a dedicated DAC?  Positional audio is important to me, but I hate the idea of having a nice set of headphones and an expensive (to me) amp being fed by a less than optimal source.
 
Thoughts?

 

[Head Injury]

What you're doing is called double amping. Sometimes this can mean more noise and distortion.
 
For example, in a normal DAC to amp setup the DAC is creating an analog signal, adding distortion and noise (THD+N) to it, then piping that to the amp which adds its own noise and distortion while it changes the voltage of the signal. In a double amping setup, the DAC adds THD+N, the amp adds THD+N, then the second amp adds THD+N. There are other problems too, like maybe the first amp is turned up too much and clipping the signal, or the circuitry of the second amp isn't designed to work well with the voltage the amp is outputting.
 
In general though it's no big deal. See, amps have very high input impedance (usually 50 to 100 thousand ohms). The more the impedance, the easier the load from the amp's perspective because it supplies less current and power. So compared to the 32-300 ohms the first amp expects to see, the 50k+ impedance of the second amp is a breeze and distortion will probably be lower than normal. And besides, most adequately designed amps (even the ones built into laptops, smartphones, etc.) will have inaudible levels of distortion with low impedance loads, so it's nothing to worry about.
 
The biggest issue is uncertainty. The amp wasn't designed to drive another amp, and amps weren't (usually) designed to be driven by other amps. Really, if you're not getting obvious issues like audible background noise, you shouldn't worry. Buy a DAC if you want to be sure. The Modi's a good option if you want to stick with Schiit.
 
Is the sound card alone not powerful enough to get good volume out of your headphones?

 

[Tranqville]

HE-400 deserves a DAC, I have O2 amp/dac combo. I remember reading on this forum that sound cards are designed to perform many different things with sound, like recording, editing, etc.  DACs are highly specialized. 

 

[PurpleAngel]

  I am currently using a Sound Blaster Recon 3D Fatal1ty Professional card outputting via the amplified headphone jack to a Schiit Asgard 2 amplifier.  I have a set of HiFiMAN HE-400 headphones with focus pads connected to the Asgard 2.  I would say I spend about 80% of my time on my PC playing games (TF2, Payday 2, Battlefield 4, or some other FPS du jour) and the other 20% divided between watching movies/TV shows and listening to chill trance and chill-step.  I am a little worried that outputting an amplified signal to my Asgard 2 is giving me a less than optimal auditory experience.
If my sound card is a weak link, is there a sound card better suited to my setup that perhaps has non-amplified outputs, but is still great for gaming?  Would I be better off with a dedicated DAC?  Positional audio is important to me, but I hate the idea of having a nice set of headphones and an expensive (to me) amp being fed by a less than optimal source.

 
An optical input DAC, like the Schiit Modi ($99), hooked up between the Recon3D and the Schiit Asgard 2 amplifier, should improve audio quality.
The Recon3D can output headphone surround sound, thru it's S/PDIF optical output.
 
You could also replace the Recon3D with the Sound Blaster Z ($85), the Recon3D and SB-Z use the same SoundCore3D audio processor.
While the Recon3D uses the DAC feature built into the SoundCore3D the SB-Z comes with a CS4398 DAC chip
The SB-Z's CS4398 DAC chip is used for the dedicated headphone output or the front speaker output.
You could daisy chain the Asgard 2 with the SB-Z, like you do with the Recon3D.
Daisy chain amplifiers is not considered desirable, but sometimes it works well enough.

 

[Airwolf]

  What you're doing is called double amping. Sometimes this can mean more noise and distortion.
 
For example, in a normal DAC to amp setup the DAC is creating an analog signal, adding distortion and noise (THD+N) to it, then piping that to the amp which adds its own noise and distortion while it changes the voltage of the signal. In a double amping setup, the DAC adds THD+N, the amp adds THD+N, then the second amp adds THD+N. There are other problems too, like maybe the first amp is turned up too much and clipping the signal, or the circuitry of the second amp isn't designed to work well with the voltage the amp is outputting.
 
In general though it's no big deal. See, amps have very high input impedance (usually 50 to 100 thousand ohms). The more the impedance, the easier the load from the amp's perspective because it supplies less current and power. So compared to the 32-300 ohms the first amp expects to see, the 50k+ impedance of the second amp is a breeze and distortion will probably be lower than normal. And besides, most adequately designed amps (even the ones built into laptops, smartphones, etc.) will have inaudible levels of distortion with low impedance loads, so it's nothing to worry about.
 
The biggest issue is uncertainty. The amp wasn't designed to drive another amp, and amps weren't (usually) designed to be driven by other amps. Really, if you're not getting obvious issues like audible background noise, you shouldn't worry. Buy a DAC if you want to be sure. The Modi's a good option if you want to stick with Schiit.
 
Is the sound card alone not powerful enough to get good volume out of your headphones?

 

  HE-400 deserves a DAC, I have O2 amp/dac combo. I remember reading on this forum that sound cards are designed to perform many different things with sound, like recording, editing, etc.  DACs are highly specialized. 
 

 
I used to have a pair of BD DT990 250 ohm headphones before I upgraded to the HE-400's.  I found that even though the sound card I am using is rated up to 600 ohms on the headphone output, low notes were getting are muddled up and crappy.  Adding a JDS O2 made a huge difference in the quality of the bass from the 990's, but didn't make much of a difference loudness wise.  I have not had any problems volume wise with the HE-400's, but I did notice that the bass was also pretty crappy when connected directly to the 600 ohm output of the card.  I actually just replaced the JDS O2 with the Schiit Asgard 2 because one of the op-amps in the O2 catastrophically failed.  I was contacted by a couple of people on other forums and was told that, in a nutshell, even though the HE-400's are 35 ohm headphones, they actually draw a large amount of current and it was about twice what the op-amps in the O2 are rated to handle.  The current theory is that this is what caused the op-amp in the O2 to explode.
 
I am not hearing any audible background noise, so maybe I should just be happy with what I have....(yeah right)

 

[Airwolf]

   
An optical input DAC, like the Schiit Modi ($99), hooked up between the Recon3D and the Schiit Asgard 2 amplifier, should improve audio quality.
The Recon3D can output headphone surround sound, thru it's S/PDIF optical output.
 
You could also replace the Recon3D with the Sound Blaster Z ($85), the Recon3D and SB-Z use the same SoundCore3D audio processor.
While the Recon3D uses the DAC feature built into the SoundCore3D the SB-Z comes with a CS4398 DAC chip
The SB-Z's CS4398 DAC chip is used for the dedicated headphone output or the front speaker output.
You could daisy chain the Asgard 2 with the SB-Z, like you do with the Recon3D.
Daisy chain amplifiers is not considered desirable, but sometimes it works well enough.

 
Thanks for the reply.  I used to have a pair of Tritton AX Pro headphones, which had 4 discrete speakers per ear (front, center, rear, and sub).  The headphones only sounded good (relatively speaking) when using the external headphone amp/connector that it came with.  It only accepted surround using an optical SPDIF connector, so I was forced to use Dolby Digital Live for surround gaming.  After 4 different sound cards (Creative X-Fi, Creative Recon 3D, some Auzentech, and an ALC on board sound) all having massive driver problems with DDL, I just said screw it and ditched the whole setup for a nice pair of stereo headphones (BD DT 990 Pro 250 ohm) and a Zalman ZM - Mic1.  Then I ran into the whole basket of kittens associated with having a high-end headphone and amplification issues...
 
I would rather not use the optical output on the card because of all the problems I have had with it in the past.  I suppose I can try a Modi, see if it has any noticeable gain in sound quality, and go from there.

 

[PurpleAngel]

   
Thanks for the reply.  I used to have a pair of Tritton AX Pro headphones, which had 4 discrete speakers per ear (front, center, rear, and sub).  The headphones only sounded good (relatively speaking) when using the external headphone amp/connector that it came with.  It only accepted surround using an optical S/PDIF connector, so I was forced to use Dolby Digital Live for surround gaming.  After 4 different sound cards (Creative X-Fi, Creative Recon 3D, some Auzentech, and an ALC on board sound) all having massive driver problems with DDL, I just said screw it and ditched the whole setup for a nice pair of stereo headphones (BD DT 990 Pro 250 ohm) and a Zalman ZM - Mic1.  Then I ran into the whole basket of kittens associated with having a high-end headphone and amplification issues...
 
I would rather not use the optical output on the card because of all the problems I have had with it in the past.  I suppose I can try a Modi, see if it has any noticeable gain in sound quality, and go from there.

 
Using an external optical DAC will give you a noise free background, as internal sound card inside the case can pick up electrical noise (the analog part).
I'm fairly sure you will notice an improvement using the Modi (optical).

 

[Head Injury]

   
 
 
I used to have a pair of BD DT990 250 ohm headphones before I upgraded to the HE-400's.  I found that even though the sound card I am using is rated up to 600 ohms on the headphone output, low notes were getting are muddled up and crappy.  Adding a JDS O2 made a huge difference in the quality of the bass from the 990's, but didn't make much of a difference loudness wise.  I have not had any problems volume wise with the HE-400's, but I did notice that the bass was also pretty crappy when connected directly to the 600 ohm output of the card.  I actually just replaced the JDS O2 with the Schiit Asgard 2 because one of the op-amps in the O2 catastrophically failed.  I was contacted by a couple of people on other forums and was told that, in a nutshell, even though the HE-400's are 35 ohm headphones, they actually draw a large amount of current and it was about twice what the op-amps in the O2 are rated to handle.  The current theory is that this is what caused the op-amp in the O2 to explode.
 
I am not hearing any audible background noise, so maybe I should just be happy with what I have....(yeah right)

"Rating" an amp up to a certain impedance doesn't mean anything. It's just marketing. 600 ohms is actually easier on an amp than low impedances (less current) but it won't get as loud. What matters is the maximum voltage or power.
 
The muddy bass could be any number of things. It could be output impedance, but unlikely if it was affecting a 250 ohm headphone. It was probably power issues, either not enough voltage swing to reach the necessary peak in time, or not enough voltage for your volume. So it was flattening peaks and distorting. What was your volume setting at?
 
The O2 thing is interesting. The designer claims it's capable of peak current around 200 mA. It was measured at 613 mW power and 4.5 V before clipping with a 33 ohm load similar to your HE-400, which means a current of 136 mA. This would be plenty of current for your HE-400, well above what you were likely using and well below the claimed maximum. Either there's a misunderstanding or the designer's measurements aren't indicative of real performance. Or you had a bum unit. I'd think someone would have mentioned this before if it was a general problem with the design, as it was under great scrutiny as it was revealed. The LCD-2 myself and many others use with the O2 is pretty hungry for current as well. Can I get a link to the discussions? (may want to PM it if it's on another forum).
 
By the way, low impedance headphones always draw more current than high impedance headphones at the same voltage. Impedance is defined as Z = V / I, Z being impedance and I being current, so as impedance goes down current must go up to match. Normally you still won't encounter high current with headphones because low impedance headphones rarely need as much voltage as high impedance headphones. Low impedance headphones with low sensitivity like planar magnetic headphones and a couple choice dynamics like the AKG K701 do need lots of current, though.