[CedricE]

I bought a Fiio E7 headphone amp to go with my v-moda crossfade lp headphones and it works absolutely great with the mini to ipod doc. Everthing is really great when I plug it into the ipod. When I use the usb plug in to my desktop the sound is not nearly as nice. Apparently the E7 is made to be USB/DAC (though I'm not really sure what a DAC is) which I'm guessing means it's made to be plugged in to a computer through USB but the sound is not as great as when I use it with an iphone through the iphone doc. Does somebody know why?
I was also looking at the Fiio E9. Is that what I need?
 
Please help!
Thanks alot
Cedric

 

[Eric_C]

Hi Cedric, welcome to Head-Fi and sorry about your wallet.
 
The E7 is a DAC + amp; the DAC means Digital-to-Analogue Converter, which can be thought of as a sound card. You need a DAC to play music stored on a computer or iPhone--the E7 just gives you the option of doing that on the E7 instead of your computer.
 
E7 can only function as a DAC with computers though, not iPhones. So with the iPhone, your E7 is only using the amp stage--which is widely acknowledged to be OK, whereas the iPhone (iPhone 4 in particular) is widely reputed to have a good amp stage.
Put simply, you don't need the E7 with your iPhone.
 
Take some time to read up on E7 and E9, there's a lot of discussion on the two here. I have not heard your headphones, but in my opinion it's probably unnecessary for you to consider the E9 for it at all.

 

[CedricE]

Thanks a lot for answering.
I know that all that I'm getting by using the e7 as a headphone amp with an iphone is a tiny bit crisper sound, way more battery, more power, and a splitting function. But why does it have worse sound when I use it as a DAC/AMP with my computer through the usb port?
 
Cedric

 

[Eric_C]

Maybe your computer's headphone jack is good? Maybe you left some EQ setting on in your computer?

 

[CedricE]

The amp inside the computer is garbage so the jack is no good. There are no EQ settings and even if there were some plugging the headphone amp through the usb port should bypass the eq of the computer since it's bypassing the computer amp no? At least, this is what I think it does...
Cedric

 

[Head Injury]

The E7 has a better amp than it does a DAC. When used with the iPhone, you're using the iPhone's DAC (which is fairly respectable) and the E7's amp. When used with the PC, you're using the E7 for both. There shouldn't be major differences, but the iPhone's DAC might perform better in some aspects.
 
From third party measurements, with a 150 ohm load (higher than yours) the amp alone performed very well with 0.003% THD at 1kHz (from line-in, like your iPhone). From USB it performed at 0.03% THD. That's still considered inaudible, but it does highlight that there are some performance differences.
 
Software equalization (like on a computer) has nothing to do with the computer's amp. It alters the signal digitally, which will happen before it outputs via USB. Make use of a bit-perfect plugin like WASAPI with your player to make sure, as well as disable all sorts of features your software player has like Soundcheck in the case of iTunes. What player do you use?
 
And don't get the E9. More power (and more output impedance) is not what you need.

 

[CedricE]

I use itunes.
If what you're saying is right, the DAC of the e7 is quite a bit worse then the DAC of the iphone.
So the e9 is not a DAC? because the DAC would be my weak link in the chain right now.

 

[Head Injury]

Quote:

I use itunes.
If what you're saying is right, the DAC of the e7 is quite a bit worse then the DAC of the iphone.
So the e9 is not a DAC? because the DAC would be my weak link in the chain right now.

No, in fact it's probably just as good, and what you're hearing is placebo. I'm just saying that it doesn't perform as well from USB. It might not even be the DAC that's the problem, because all the measurements were taken with the amp. That's just my assumption. It might have issues with clean power from USB.
 
The E9 is just an amp. Usually you plug the E7 into it and use the E7 as a DAC.
 
Make sure you have all features of iTunes turned off, like EQ and Soundcheck. Keep digital volume maxed, or within a few dB of max (might help the E7 perform a little better if it's just below maxed). There should be a kernel streaming plugin or something similar for iTunes somewhere. I'll let someone who knows their way around the program help you there.

 

[CedricE]

What's a kernel streaming plugin?