Up for sale is a nice Sylvania 5751 vacuum tube with original Sylvania box, tested strong and well-balanced. This tube tested with gain readings of 80 / 81, showing excellent balance between both triode sections. Transconductance / mA readings were 1.71 / 1.63, also very close and strong. It was also tested for microphonics and noise. Low microphonics — tap is audible when the tube is tapped, but it dies out quickly with no ringing or excessive feedback. A very nice choice for audio use, guitar amps, hi-fi, phono stages, preamp circuits, and anywhere a quality 5751 is desired