Editing 6SN7 (section)

== Usage ==
[[File:6SN7 tube by JJ Electronic.jpg|right|thumb|150px|6SN7 by [[JJ Electronic]] ]]
The 6SN7 was used as an audio amplifier in the 1940-1955 period, usually in the driver stages of power amps.  The designer of the famous [[Williamson amplifier]], one of the first true [[high-fidelity]] designs, suggested use of the 6SN7 (or B65) in his 1949 revision since it is similar to the original circuit's '''L63''' (=6J5) British single triodes, four of which were used in each channel of his 1947 circuit.

The 6SN7 was one of the most important components of the first programmable electronic digital computer, the [[ENIAC]], which contained several thousand of the tubes. The [[Semi Automatic Ground Environment|SAGE]] computer systems used hundreds of 5692s as [[Flip-flop (electronics)|flip-flop]]s.

With the advent of television, the 6SN7 was well suited for use as a vertical-deflection amplifier.  As screen sizes became larger, voltage and power headroom became insufficient.  To address this, uprated versions  with higher peak voltage and power ratings were introduced. The '''GE 6SN7GTA''' (GE, 1950) had [[anode]] dissipation uprated to 5.0 watts. The 1954 GE 6SN7GTB also had  controlled heater warmup time, better for [[Series and parallel circuits|series]] heater strings.

The 6SN7 was considered to be obsolete by the 1960s, replaced by the [[12AU7]], and became almost unobtainable. With the introduction of [[semiconductor electronics]], vacuum tubes of all types ceased to be manufactured by the major producers. A small demand for vacuum tubes in [[guitar amplifier]]s and very expensive high-fidelity equipment remained.  As existing stocks ran out, factories in eastern Europe and China started to manufacture the 6SN7, and higher-gain '''6SL7'''.  {{As of|2019}}, 6SN7s and 6SL7s are still manufactured in Russia and by [[JJ Electronic]], and are widely available.<ref>[http://www.hotroxuk.com/electro-harmonix-6sn7eh.html?gclid=EAIaIQobChMImJT64sXp4wIVgrHtCh2BVw45EAQYAiABEgK67vD_BwE Available to buy]</ref>