I just received my E7 today...and found the it to be completely worthless while being fed via the HPO.....LOD and USB is good though.... no 10 or 15 volume but a 20-25... i mainly use my Fuze for on the go...and my T3 works just fine via the HPO... makes me want to get a LOD for the fuze now.... aarrghhh!!!!

Can anyone explain what an "LOD" is? I'm looking to amp my iAudio9 + HD 25 II setup. So if i understand correctly, sticking an E7 directly into the headphone out on my i9 won't make a difference in volume/SQ? I'm confused now.

Quote:

aizura said:

Can anyone explain what an "LOD" is? I'm looking to amp my iAudio9 + HD 25 II setup. So if i understand correctly, sticking an E7 directly into the headphone out on my i9 won't make a difference in volume/SQ? I'm confused now.

Click to expand...

for some it works...but recently there has been an issue where the gain is off when the e7 is fed from a headphone out.... LOD is line out dock.... it basically bypasses an mp3 player inner circuitry like the built-in amp in mp3 players....but when using a LOD an amp is needed to hear or adjust volume.

What are the chances it won't work directly out of the HPO? Is this a known issue or are there only a few cases of this problem? What LOD could i use for my iAudio9 anyway?

Hi,
 
The E7 provides about 4dB of gain to the analog input. What this means is that if your MP3's headphone output is weak, then the E7 will only provide a modest bump in volume above that. Some MP3 players have fairly high signal levels for their headphone outputs, so there is no lack of volume. But some MP3 players, like the Teclast T51, have a very weak headphone output, in which case the E7 may not be the solution if the goal is to get a lot more volume. This is only an issue if you are limited to the headphone output of a MP3 player, as the E7 provides ample output volume when fed from a line-out signal or from its internal DAC by a computer. So with the Teclast T51 as an example, its line-out works great with the E7.
 
Jack

is here anyway to repalce feedback resisitor to adjust the gain?  

Gain is set by the opamp (power amp chip), not by resistor..

The E7, if I am guessing correctly, has an Analog Devices input buffer chip that feeds into a TI power amp.  The TI power amp is the one responsible for the adjustable gain. Its data sheet indicates 60 levels of volume adjustment, which is what the E7 provides. Unity gain is at about step 56, below which the TI power amp is actually producing a voltage that is lower than the input signal, but at a greater current capacity. This TI part is highly integrated and I don't think you can do much to massage things here.
 
The only chance lies in the input buffer stage, and I don't know how hard it would be to change the gain there, or even make it user selectable.
 
Jack

"unity gain is at about step 56",
so if I understand this correct, the only way to use e7 as amp is to set step 56 or above. 
 
* just check the data sheet of TPA6130A2, it has 64 step adjustment. 0.1db gain is on step 54, since it is prebuilt amp chip already, this is no way to change the amp gain. so please set step to 56 or above to use as headphone amp.

No, this is not quite the right way to think about it.
 
If the only goal is to "increase output from a headphone output of a DAP", then yes, one would need to set the FiiO at step 56 or beyond.  However, this isn't the main goal of a headphone amp, nor is it how most headphone amps are used. 
 
When you feed the FiiO a signal through its own internal DAC, or via the line out of a source component, you will almost certainly have to set the volume lower than 56, unless you are trying to drive some very high and/or very inefficient headphones. 
 
Even when feeding a headphone output to the E7, you might take advantage of the superior amplification performance of the E7 by setting the volume of the source to fairly high to get a good clean signal with good SNR, bandwidth, separation, low distortion, etc. Then you would use the E7 to modulate the output to a desired level. 

Sorry to revive an old thread, but i'm with the OP here.
I bought a E7, and tried it, funnily enough, the E5, being almost 1/5 of the price did a better job with Headphone in/out.
The bass was more responsive and louder/impact, the sound was louder and clear. More so, the e5 was easier to carry around and much less heavier.
 
I thought the e7 for me would have been a good investment, but after using them with the W2's + ipod or even connecting it to my PC, i found out that it was a waste of money.
 
Sorry to say
I might not realise it's full potential but for me, directly connected to an iPod i wouldn't suggest it AT ALL.
 
I personally thought it was faulty, as i was playing it at volume 60 with BB at 3.
So i sent it back to the ebayer (which i bought my e5 from), and he will hopefully refund me the full price i paid: £50 + 3 postage
 
Hope that helps some people...

IMO - Ipod no but PC yes
 
It been said many times that its primarily designed for PC / DAC use and it does a decent job at that, listening to my E7 now via my PC the volume is at 12 , 20+ is loud .  Fiio said in their post here have said that in the next version they will be increasing the gain to make it more viable as an amp only for PMPs.  If you want a cheap external DAC for your PC with bass boost the Fiio e7 should be in your top 3 choices.