Hello, I cant use headphones anymore (health issue), this is a O2 Headphone Amp with a rear rean-tiny PSU connection. http://nwavguy.blogspot.com/2011/07/o2-headphone-amp.html

... now you know ...   If you regulary discharge your battery at 100%, it really harms the battery. If you battery stay for a wile at 100% discharge, it really harms the battery a lot if it don't kill it directly.

Hello, i've got two first batch units and the batteries are still ok. This guy is not lucky for two reasons, the defective batterie and the manufacturer very bad mentality (they are all the same when they are as big as Sony)   You should try to open it and try to find technical informations...

  Yes, you should also verify the DC offset of your vinyl rips.   http://manual.audacityteam.org/man/dc_offset.html

  Put multimeter on the 2V DC caliber at the jack output connector of your DAP.

Fiio... it is a great brand. BUT you should measure the DC offset of your DAPS ASAP. I've got a DC issue in the past that kill one of my CIEM armature...

Hello, Are you using a bass boost ? Is your amp pariculary well known to have a good bass rendering ?

  Hello, Are you sure that they are in parallel ?   It looks like serial polarized capacitors... 1.1µF

Yes they are. As described by manufacturers !

The poor cat is blocked in a concrete filter... how set him free ? He should be so scared !       Sorry i was digressing a lot.

    ... i fooled myself... RC filter is RC, it is just R and C.  

    RC high pass need an inductor and the phase shift of a 4th order is 360°.

Wow... every component have a inductive, resistive and capacitive part.   So all IEMs have a very complex 4nd order filter, Amazing discovery !   Really.

Yes, with UV gel you can take the time you want to position your tubes perfectly.   PS : Nail art UV gels are not gels at all, they are high viscosity fluids, otology gel resin does not flow at all because it is a REAL gel.