So has no one done a comparison between the Amperiors and the DT1350's yet? I just searched through about 25 pages of people saying they wanted comparisons, but none were ever made.
I'm still using the DT1350's and love them for portable use. I did some calculations based on "another previous members" blog article. These are calculations for using the DT1350's with the SanDisk Sansa Clip+, which I now use as my portable player and it sounds excellent with the DT1350's unamped, and here's why...
DT1350's have a nominal impedance of 80 ohms and 109 db-SPL @ 1mW (often written 109dB, or 109 db/mW)
The Sansa Clip+ has a power output of roughly 15mW into a 16 ohm load. That would be 3mW into an 80 ohm load (DT1350's). This is already good news knowing that we can achieve 109 db-SPL with only 1mW.
The maximum output of the DT1350's from the Sansa Clip+ is:
dBSPL = Sensitivity in dB/mW + 10 * LOG ( Pmax in mW)
= 109 + 10 * LOG(3)
= 119.9 db-SPL
That's great news, these things can rock out.
To calculate the power consumed by the DT1350's to drive them to a "comfortable" 105 dB...
Power in mW = Antilog ( ( Desired SPL - SPL at 1 mW ) / 10 )
= Antilog ( (105 - 109) / 10 )
= 0.398 mW.
At max output, the DT1350's can get 3mW, so 0.4mW for comfortable listening is nothing.
EDIT: I wanted to add one more thing. The output impedance of the Sansa Clip+ is only 1 ohm so anything 8 ohms or higher can be matched well with the Clip+, meaning any IEM can be driven from these.
The DT1350's can be driven by the Sansa Clip+ easily with no amp required.