Sound Card Versus Amplifier

[Menel]

I'm planning on purchasing a pair of AKG K701's in a few days. I understand they require an amplifier to perform at their peak (or close to it depending on the amp i guess). But basically my question is would a sound card like the
Asus Xonar Essence
ASUSTeK Computer Inc. - Multimedia - Xonar Essence STX

which has a built in headphone amplifier be better than a amplifier of the same price? If have a good sound card already.

As you can probably tell I'll be using the K701's mainly on my computer.

 

[wakibaki]

It really does depend on which soundcard you already have, but a standalone headphone amp can be as good as or better than the one built into this card, can be used with any source including an upgraded soundcard if you buy one in future, and will probably be cheaper to buy at the same quality level, certainly cheaper than one combined with a soundcard. Most people would prefer an independent amplifier is my guess.

w

 

[jcx]

the < US$200 external headphone amp market is unfortunantly full of poor examples - at such low price its hard for anybody to provide case work, power supply, even mediocre volume pot - as raw parts cost - much less assembled, shipped and any profit allowed for

so by using PC power supply (even if not "optimum" for audio), likewize case, pcb "included", and not having to purchase a reasonably matching stereo analog log pot when volume is software controlled - a soundcard can give very good competition to cheap headphone amps

the TPA6120 headphone ouptut op amp is very good technically so it is likely the Xonar Essence STX is a good audio quality choice at that system price compared to adding an extenal amp of the same cost as the card

the reviews are frustrating - I didn't find loaded headphone output plots or convincing output specs beyond the manufacturer's ad copy, but the TPA certainly can supply the current required by K701/2
there is a question as to the real Vswing limits - with the external "molex" power connector it has at least +12 V supply so its probably AC coupled - which could give up to ~3.5 Vrms with gain enabled
but it would be nice to know what the series R and DC blocking cap values are

with the assumption of +12 V single supply and the TPA6120 app circuit 10 Ohm series R you may be able to drive the k701/2 to ~110 dB SPL - good, but not good enough as your "final" audiophile solution

but I will admit I am in a minority in thinking that the 120 dB SPL required to reproduce some live event acoustic music without clipping is a minimum "audiophile" headphone+amplifier system requirement

 

[wakibaki]

the < US$200 external headphone amp market is unfortunantly full of poor examples - at such low price its hard for anybody to provide case work, power supply, even mediocre volume pot - as raw parts cost - much less assembled, shipped and any profit allowed for

I can buy a TPA6120 in the UK for <$3 US, and a wall-wart for no more than $10 shipped, so you should be able to find a standalone HP amp of identical quality for less than $200.

I found this tube amp for $145 plus shipping:- Xiang Sheng 708B Stereo Tube Headphone & Pre Amplifier - eBay (item 310237689361 end time Aug-02-10 23:02:20 PDT)

...that's not a recommend, just an example of what you can get <$200. They 5 tubes in that baby...

w

 

[jcx]

cheap tubes aren't a good match for K701 low sensitivity and impedance which requires more current than many headphones

I would like to see how many of those tube amps are actually legal in US/UK/Eu - ie have national safety lab rating


direct sale China/SE Asia manufacture solid state could do better performance wise but many don't

at least one lower cost TPA6120 based headphone amp product faded away fairly quickly: Xenos 1HA-ECT was dropped 1st then the "discrete transistor" output stage version died too


please feel free to make a small fortune making and selling sub US$200 headphone amps - but I'm pretty sure the most likely way to do that is to start with a Large fortune and lose money on every sale unless you can push product volume to some high multiple of K units/yr

 

[Menel]

Thanks for the advice guys.
It seems like a sound card is the way to go for me atm.

Any opinions on the Auzentech Bravura? Auzen X-Fi Bravura from Auzentech, Inc. : World First soundcards for Music, HTPC, and Gaming.

Or having seen Indeed-hi-fi-labs be linked elsewhere on these forums
indeed-hi-fi-lab items - Get great deals on Integrated Amplifiers, Preamplifiers Controllers items on eBay.com!
What would be the quality on any of those amps be like?

 

[qusp]

yeah the prelude is well regarded on head-fi. I havent had the pleasure myself, but if you have the ability or will, you can apparently make quite a nice system with a few opamp and power supply mods. the stock unit is already pretty impressive for the money. PCM1794A DAC and having experience with that headamp chip, pretty clean sounding amp section. an easy mod for balanced line output too I would think.

I might have read something about the bravura running hot

 

[DualTriode]

I can buy a TPA6120 in the UK for <$3 US, and a wall-wart for no more than $10 shipped, so you should be able to find a standalone HP amp of identical quality for less than $200.

I found this tube amp for $145 plus shipping:- Xiang Sheng 708B Stereo Tube Headphone & Pre Amplifier - eBay (item 310237689361 end time Aug-02-10 23:02:20 PDT)

...that's not a recommend, just an example of what you can get <$200. They 5 tubes in that baby...

w

Hello All,
I bought a 708B I ended up installing all NOS 6DJ8’s and 5670 the original power rectifier remains. The tube in the window is just for show, I think. I replaced the volume pot. I changed out the tubes just because. The pot tracked very poorly at low level. Sounds ok. I do not know the output impedance.
Headphones and headphone amplifiers should be selected as a set. If you have the money to play with the 708B may work well. However it is hard to send them back.
DT
All just for fun!