What bothers me is the high output impendance , I thought my 8ohm soundmagics sounded "wrong" plugged into the e9's 3.5mm socket.
E9, for all its intention, is really designed for hard-to-drive headphone in mind. I have another DAC / AMP with the same TPA6120 chip, and it has about the same output impedance issue driving low impedance headphone and IEM. Hence why E9 and E7 are meant to pair together. One handles high impedance headphone while the other handles the low impedance stuff.
The reason is that the loader is not " pure resistor ", the real headphone/earphone includes resistor, capacitor and inductance.
A resistor connect to a capacitor or inductance will change the frequency response.
BTW , the 10 ohms resistor is the design request by the TI. it is for safe.
What I means is consider the headphone/earphone as a pure resistor.
I am not sure, but it will be ok if you only want to enough volume, but sometime you want better SQ and it also depend on your taste of the SQ.
mine after 30 or so hours does not sound the same... right after out of the box was quite mechanical and harsh sounding but now it has improved a lot...
ok it isn't in any kind mellow, "musical", sweet... etc etc.. I would just say accurate for now... I think more accurate than my phones :)
More specific impressions after some more hours... for sure it makes me want to buy more phones..
Is anybody using it with Fisher Audio FA003 or FA011???