The Xonar Essence STX Q/A, tweaking, impressions thread - Page 270

For $50 up can replace the three stock op-amps on the STX (AD797BR).

Hello, having a little problem with my STX and I was wondering of anyone could help me out :)

I was told on a number of occasions that the Xonar STX would be more than enough to drive a pair of Q701's despite people buying E9's and what not. However I'm struggling to get them to any decent volume even at full volume! Not that I ever have them at full because there is this popping sound that occurs when ever i go over 30% volume... :(

I have the most up-to-date drivers from ASUS and have turned on the HP "Extra High Gain" setting, that has got me where I am now. Does anyone have any ideas? Do I need an external amp? (Bearing in mind I spent all my money on a GTX 670... :/ lol)

Thank anyway,

-Tom

Well, STX is primarily a DAC, not an headphone amp. Although its marketed as an audiophile card to headphones, to be quite perfectly honest, the amp is holding the rest of the card back, I mean really holding it back. Think of it this way....a DAC with measured performance comparable to 1000$ standalone DAC's connected to an afterthought 50$ head amp. That's the story of STX.  People love it for its sound quality, as a DAC, not as an head amp. While the headamp section has power to run headphones, and will sound better than any other soundcard and virtually any external DAC+amp combo for the price, its amp is far behind the DAC section in terms of sound quality.  I absolutely HATE how it sounds with my Q701 for example, its almost not listenable with most music. But use the stereo out into an external amp, and you'll see it in full glory. Try getting a hold of some external head amp and try it that way before selling it.

But anyway, not to bust your balls, but if you're not impressed with STX, you wont be with anything else as far as DAC's go. You've climbed to the 8500 meter mark on your way to the top of Mt. Everest. Those extra 350 meters to reach the absolute best will cost you a little fortune. I went on, spend 2000$ on DAC's that are suppose to be much better, even won awards for best DAC for 1000$, but hell, they werent any better than STX. I mean, just saying, if you're gonna return the STX, know in advance you're not getting anything nearly as good for the same price, and nothing better unless you wanna spend about 10 times more money.  Better spend 200-300$ on an amp, get something like a Matrix M-stage, and you'll be as happy as a pig in mud.

Well, STX is primarily a DAC, not an headphone amp. Although its marketed as an audiophile card to headphones, to be quite perfectly honest, the amp is holding the rest of the card back, I mean really holding it back. Think of it this way....a DAC with measured performance comparable to 1000$ standalone DAC's connected to an afterthought 50$ head amp. That's the story of STX.  People love it for its sound quality, as a DAC, not as an head amp. While the headamp section has power to run headphones, and will sound better than any other soundcard and virtually any external DAC+amp combo for the price, its amp is far behind the DAC section in terms of sound quality.  I absolutely HATE how it sounds with my Q701 for example, its almost not listenable with most music. But use the stereo out into an external amp, and you'll see it in full glory. Try getting a hold of some external head amp and try it that way before selling it.

What's so bad about the amp?

It is not bad, in fact it is quite good with high impedance headphones, but not so much when using low impedance and/or very sensitive ones:

- the 117 dB SNR is meant for full scale (7 Vrms) output, and 48/96/192 kHz sample rate. Since the card has fully digital gain and volume control (= constant absolute noise floor), and the DAC becomes noisier at 44.1/88.2/176.4 kHz sample rates, it can actually have audible hiss listening CD audio with the most sensitive headphones or IEMs

- there is a slightly higher than 10 Ω output impedance; that can audibly affect some low impedance headphones, and especially balanced armature IEMs

- the 0.001% distortion is measured with a high impedance load. When loaded with a few tens of Ω instead, the distortion is not quite as good, although still not poor

- there is a relatively high 28-29 mV DC offset

None of the above really explains the claim by derbigpr that the amplifier performs poorly with 300+ Ω Sennheiser headphones, though.

It is not bad, in fact it is quite good with high impedance headphones, but not so much when using low impedance and/or very sensitive ones:

- the 117 dB SNR is meant for full scale (7 Vrms) output, and 48/96/192 kHz sample rate. Since the card has fully digital gain and volume control (= constant absolute noise floor), and the DAC becomes noisier at 44.1/88.2/176.4 kHz sample rates, it can actually have audible hiss listening CD audio with the most sensitive headphones or IEMs

- there is a slightly higher than 10 Ω output impedance; that can audibly affect some low impedance headphones, and especially balanced armature IEMs

- the 0.001% distortion is measured with a high impedance load. When loaded with a few tens of Ω instead (see here, for example), the distortion is not quite as good. Of course, some distortion will also result from the output impedance. Overall, it is still acceptable, though

- there is a relatively high 28-29 mV DC offset

None of the above really explains the claim by derbigpr that the amplifier performs poorly with 300+ Ω Sennheiser headphones, though.

I do not think it makes much difference, but I included it for completeness. Maybe for some very sensitive headphones that cannot handle much power. By the way, the FiiO E10 has similar or slightly higher DC offset on high gain.

My measurements on my modded STX were half of the D.C. offset you quote out the headphone jack (about 10mVin one channel & 15mV in the other). Other people have measured the same on thiers. Note that nothing was changed from stock as far as the headphone output was concerned, only the line out was changed on mine (Caps remove from output). Other mods were strictly powersupply.

Nothing really, I guess some expect it to compete with high end/high dollar external headamps.  They forget the price and performance available for the overall package.

None of the above really explains the claim by derbigpr that the amplifier performs poorly with 300+ Ω Sennheiser headphones, though.

Sorry, but I never ever said it performs poorly with 300+ ohm headphones, don't put words in mouth please, I even used it with such headphones. It just doesn't perform (with none of the headphones) as good as a decent external amp, or with something like a integrated speaker amp headphone output. And yes, a headphone output on my speaker amp is superior in every regard, regardless of specs. It sounds bigger, punchier, more detailed, more airy, more musical, everything sounds more separated, etc. Thats the biggest problem with STX amp, everything sounds congested, soundstage is small and the music just doesn't sound coherent as it does on regular amps.  STX headphone out is good, for the price, but not nearly as good in practice as the specs say or as good as the DAC section. That's clear when you compare it to a cheap separate head amp with inferior specs, but it actually sound better.