I won't (and I can't) do a fully descriptive and detailed review of QC25s being used alone vs. being amped, as I'm in no way a master reviewer. But, I'll try something...
It goes like this : iTunes playing Phil Collins'
Dance into the light via a MBA > without and with an Audioquest Dragonfly (not the big rig, but it satisfies me enough) > Bose QC25 with NC off and on.
I choose this song because it has a lot of different instruments in it, and being it the most played in my library
It may not be the best tune for testing things out but, I like it anyway! And if I'm gonna be listening to it 4 times in a row, must it be one of my favorites! Finally, please note that volume setting for 1. and 2. was at 75% (12/16), and 3. and 4. was at 50% (8/16). Despite this, volume level with 3. and 4. was a little bit more powerful. I wanted to keep the effect of the DAC/amp, but not at the point that volume alone makes me think of a better sound.
1.
Not amped, NC
off : you already know. As @
MacedonianHero, and I too, previously mentioned, it sounds dull. Lacks a little bit of everything : definition, omph, sparkle, etc. Not the big deal, but nothing to make you ill!
2.
Not amped, NC
on : you already know this, too. Sound is much more complete, way more exciting. It gets all, if not perfect, at least very good.
Now, what you've been waiting for!
3.
Amped, NC
off : first, it really does give it more power (see note above about volume setting), something the QC25s seems to like. Sound quality however… It gives it some kicks of life, is better than number 1. but nothing near of number 2. Bass is lacking, both in quantity and quality, and don't seems to go as low as with number 2. Not as detailed too. Voice is (a little bit less, but) still congested.
4.
Amped, NC
on : Honestly, not a big difference here compared to number 2. I noticed maybe the xylophone at 1:55 to stand out a little bit more. Overall definition tends to be slightly better.
Differences are more prominent between NC off and on, than it is between amped an unamped.
If I may classify the sound quality, for your convenience, it should go like this :
Amped, NC on : 9/10
Not amped, NC on : 8.5/10
Amped, NC off : 5.5
Not amped, NC off : 4.5
So, I really think these headphones are meant to be used as a mobile set, with their own amp, since you don't gain that much with, at least, a Dragonfly.
As I don't have a "true" audiophile ear, nor a real big rig, I suggest you wait for @
MacedonianHero results.
