Objective2 Low Power Option Kit

 This kit contains the three opamps and some passives to convert the Objective₂ amplifier to the low power version for an extended battery life

2x - Texas Instruments TLE2062CP (replaces U3 and U4)
1x - Burr Brown OPA2277PA (replaces U1)
all passive parts needed are included as well

this simple change is worth to consider if

a.) you use your Objective₂ mainly on battery power and
b.) your headphones have an impedance of 32 Ohms or higher.

More details can be found in NwAvGuy's blog article here