The LISA III Portable headphone Amplifier represents the accumulation of over 6 years into the refinement of My Buffered Multi-Loop Portable Headphone Amplifier Topology utilizing a Dedicated ground Channel to Drive the Headphones Differentially and avoid the Contamination of the Systems Quiet Ground by the Reactive Load created from Back EMF (Electromotive Force) of the Headphone drivers. The Original version of this Amplifier (The PPA), More commonly Known as “Phil’s Portable Amplifier”. “Defined The Art” for Portable Headphone Amplification. This Amplifier retains the Basic Core structure of the PPAv2, However adds a substantial size Reduction and a more efficient Multi-Loop Negative feedback Circuit topology than the Original.  More...