1、1U4 (triode connected): Medium MU small mass filamentary heating structure.
三極管接法)：中Mu小型燈絲結構。

2、Hum produced from within the filamentary structure.
燈絲結構本身所產(chǎn)生的HUM。

3、6B4G: Low MU Oxide Coated filamentary heating structure.
低Mu氧化物覆膜燈絲結構。

filamentary翻譯