Low noise the pl50, a high quality linear power supply, brings to your sound a lower noise floor, more refined dynamics and transients, and a more accurate, warmer tone to lower frequencies. Since the low frequency noise of linear power supplies is fixed in frequency, this noise can be better and more accurately filtered out. In addition, the large pl50 is also equipped with a filter circuit at the end of the ac, for filtering out interference generated by other electrical devices used on the same ac circuit for even cleaner and more stable power. Excellent custom high quality transformer the pl50 features a custom 50va audiophile grade toroidal transformer, made of high quality nippon steel iron and high purity oxygen free copper wires for higher efficiency, higher precision, more stable voltage, and higher energy output. They by their very nature have numerous advantages, allowing them to be very efficient. This is due to the coils in the transformer not having a set angle at which they are bent, leading to a more uniform magnetic field and less magnetic flux leakage. Complex but perfect circuit design the pl50 features a complex circuit design that has been fully thought through to ensure reliable operation. Emi filtering, transformer rectification, voltage regulation sampling, and multi stage filtering are all parts of the circuit design so that you can use the pl50 without worry. Practical outer shell as with other products employing fiio's industrial design, the outer shell of the pl50 is made of aluminium magnesium alloy, which not only gives the unit a more refined texture, but also effectively shields the internals from external noise and interference. Safety certificated assured reliability the fiio pl50 has been designed and manufactured according to strict safety standards, and has obtained various international safety certifications allowing you to be reassured of its reliability. Comparison between old and new versions the old and new design versions of the pl50 have exactly the same functions and configuration, the only difference is the design of the panels.