Up for sale is a single piece (1 PC) of highly desirable vintage Sylvania 6SN7GT dual triode vacuum tube, branded for Mullard and packed in a white box. Manufactured in the USA by Sylvania, this early-production tube features black plates, a bottom square getter, and a smooth black base. Highly coveted in the high-end audio community for its exceptional dynamic extension, airy soundstage, and detailed clarity in Hi-Fi preamplifiers and driver stages.

As shown, the tube has been thoroughly tested on an advanced Amplitrex AT1000 tube testing system in full fixed-bias mode. Plate current (Ip) and mutual conductance (Gm) measurements alongside percentage performance ratings relative to nominal factory specs are detailed in the table below.