Thanks Raja, your help is really appreciated.Regarding the Fiio amp, this reviewer says that the extra 33 ohm on the small jack could have been added to prevent accidental headphone damage on lower impedance models http://nwavguy.blogspot.ro/2011/05/...

Thanks Raja.I think the Fiio uses the TPA6120 for both outputs since I wasn't able to find any information that says otherwise.Can you also gelp with these questions?- Does the STX have more power since its maximum gain is 18 dB and Phoebus' maximum ...

Thanks for the reply Raja.I avoided looking at the datasheet since the output impedance could also depend on the implementation. For example, the Fiio E9 which uses the same TPA6120 has an output impedance of 10 on the large jack and an output impeda...

Thanks for your reply. However, I was asking about the output impedance and not about the output gain. For more details about the output impedance see the following article:http://nwavguy.blogspot.com/2011/02/headphone-amp-impedance.html

Isn't anyone able to help?