Question for FiiO:
I just received a used pair of FT3 to go with my first pair of FT3. I am using the suede pads on the pair I just received and the leather pads on my original pair. I always check the driver resistance with my digital multimeter when I receive a pair of phones or iems to confirm that the drivers are well matched to each other. Checking the resistance isn't the same as checking the impedance, but it will tell you how closely matched the drivers are. Normally you will see a small difference between the drivers, but if you see a larger difference, it can mean there is a problem with one driver. On my original pair of FT3 the drivers measure 343-ohms and 347-ohms. On the pair of FT3 I just received the drivers measure 343-ohms and 371-ohms. The driver that measures 371-ohms is, to me, out of spec and indicates some sort of problem. When one driver is too far apart from the other driver, you will usually hear an imbalance in the sound. I think I am hearing that the 371-ohm driver is slightly lower in volume than the 343-ohm driver, which would be normal since the higher resistance driver should be somewhat less efficient than the 343-ohm driver.
My question to FiiO is, do you consider the 371-ohm driver to be out of spec and should I return the phones for another pair?