You get the best answer if some one who used the valhalla with the headphone comes in here.
Will a fiio e7 power an AKG K702? (To reasonable levels) - Page 2
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FiiO E7 is limited to about 50 mW into the ~62 ohms of the K702 (1.7V). That's probably more than any laptop except rare exceptions. At higher impedances it's still limited around 1.7-1.9V. Taking the least sensitive of the K701 and Q701 sample data on InnerFidelity and rounding down, that would be around 104 dB SPL maximum from the E7 with those headphones, pretty loud for a lot of recordings.
If you look at the sensitivity data for DT 990 250 ohms, assuming the Pro isn't quieter than the Premium, at a given voltage, the DT 990 250 ohms should be quieter than the K702:
And the voltage an E7 can supply to the K702 exceeds what a typical laptop or an iPod could put into a DT 990 250 ohms (or any headphone).
So the K702 with E7 will be louder than DT 990 250 ohms with a laptop / iPod.
So I am brand new to head-fi. About 4 years ago, I got a pair of Bose QC2 headphones, and since about 6 months ago I've been listening to all my music in FLAC. After reading enough posts on forums like head-fi, I learned that Bose is an acronym for 'buy other stereo equipment' in the audiophile community. So a few weeks ago I decided to try to continue the progression into higher quality sound that I've been following and buy a better set of phones and a DAC and amp. I decided to shell out now for a good set of headphones and buy a less expensive DAC and amp that I can upgrade later. I recently bought the AKG k702 and a Fiio e7 and am in the process of breaking them in. I still have maybe 80 more hours to go. I am pretty green with respect to the equipment that properly powers headphones, but I did feel like I could tell that the e7 amp was not powerful enough to power the 702 while I was listening to Dark Side of the Moon. I returned the fiio e7 and am considering the e17, and from fiio's website, the specs for the e17 have an output of 30-250 mW which is greater than the e7 with an output of 16-150 mW. I'm guessing that's the spec of the amp that determines how loud the phones get, but I don't know. Can anyone with experience with the e17 or 702s confirm that the e17 is an adequate begginer DAC and amp? Are there other combinations that would be an an adequate DAC amp combo for a pretty limited budget of around $140?
- 392 Posts. Joined 8/2010
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For a few bucks more you can have the O2 amp, im sure it will do a better job driving the Akg.
But is not portable as the E17.
- 34 Posts. Joined 4/2012
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I have both the E17 and the O2. The E17 is, IMO, an excellent value for the money. For several months I used it to drive my K702s at my desk, and it did a very nice job. With the gain set at +6, I was able to get a very decent sound out of those phones. I was quite surprised by the quality. Recently I purchased an O2 from JDSLabs and I feel that I am finally satisfied with an amp for my AKGs. The O2, I think, makes the K702 sound the way they were intended to sound. It's very analytical to be sure, but very, very nice. I've moved this combo to my main listening room where it competes for head time with my Grado 325is and my Woo WA6.
So yes, the E17 will be fine for a start. The O2 however, especially with the K702s, is in another league, but it is also a great value. You will however need a DAC. I'm using an HRT Music Streamer II. It's a very nice combo for the money.