I just build a headphone impedance Up/down transformer matching converter. It only need permalloy step up/down transformers + 6,35mm Jack x 2. 1 for Input , 1 for output , together with a 6.35mm Plug x 2 Cable. it can convert high impedance Headphone amps to adapt low impedance & convert low...

This Circuit is design by ASL Joseph Lau. It topology is simuliar to Jade but use Jfet + Mosfet. It is simple and easy but good sound. It is patented in China. It output can get from D or S or get both to become balance output.

I'm working on OTL Headphone amp design to drive low impedance Headphone. It seem to be many choice like cathode follower , White cathode follower & Futterman SEPP ................ What topologies is most powerful to dirve low impedance Cans ? I like to compare sound quality & Driving ability...