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mw.loader.load(["mediawiki.page.startup","mediawiki.legacy.wikibits","mediawiki.legacy.ajax","ext.centralauth.centralautologin","mmv.head","ext.visualEditor.viewPageTarget.init","ext.uls.init","ext.uls.interface","ext.centralNotice.bannerController","skins.vector.js"]); }</script> <link rel="dns-prefetch" href="//web.archive.org/web/20140817094520/http://meta.wikimedia.org/"/>  </head> <body class="mediawiki ltr sitedir-ltr ns-0 ns-subject page-6SN7 skin-vector action-view vector-animateLayout"> <div id="mw-page-base" class="noprint"></div> <div id="mw-head-base" class="noprint"></div> <div id="content" class="mw-body" role="main"> <a id="top"></a> <div id="siteNotice"></div> <h1 id="firstHeading" class="firstHeading" lang="en"><span dir="auto">6SN7</span></h1> <div id="bodyContent" class="mw-body-content"> <div id="siteSub">From Wikipedia, the free encyclopedia</div> <div id="contentSub"></div> <div id="jump-to-nav" class="mw-jump"> Jump to: <a href="#mw-navigation">navigation</a>, <a href="#p-search">search</a> </div> <div id="mw-content-text" lang="en" dir="ltr" class="mw-content-ltr"><p><b>6SN7</b> is a dual <a href="/web/20140817094520/http://en.wikipedia.org/wiki/Triode" title="Triode">triode</a> <a href="/web/20140817094520/http://en.wikipedia.org/wiki/Vacuum_tube" title="Vacuum tube">vacuum tube</a> with an 8-pin <a href="/web/20140817094520/http://en.wikipedia.org/wiki/Tube_socket#Octal_base" title="Tube socket">octal base</a>. It provided a medium gain (20). Note that ‘6SN7’ is not an actual tube designation<sup id="cite_ref-1" class="reference"><a href="#cite_note-1"><span>[</span>1<span>]</span></a></sup> but indicates a <i>family</i> of tubes such as 6SN7-GT... the 6SN7 was mostly made in a <a href="/web/20140817094520/http://en.wikipedia.org/w/index.php?title=GT_size&action=edit&redlink=1" class="new" title="GT size (page does not exist)">GT size</a> glass envelope. The 6SN7 is basically two <b>6J5</b> triodes in one envelope.</p> <div class="thumb tright"> <div class="thumbinner" style="width:107px;"><a href="/web/20140817094520/http://en.wikipedia.org/wiki/File:6SN7tube.jpg" class="image"><img alt="" src="//web.archive.org/web/20140817094520im_/http://upload.wikimedia.org/wikipedia/commons/7/72/6SN7tube.jpg" width="105" height="217" class="thumbimage" data-file-width="105" data-file-height="217"/></a> <div class="thumbcaption"> <div class="magnify"><a href="/web/20140817094520/http://en.wikipedia.org/wiki/File:6SN7tube.jpg" class="internal" title="Enlarge"><img src="//web.archive.org/web/20140817094520im_/http://bits.wikimedia.org/static-1.24wmf15/skins/common/images/magnify-clip.png" width="15" height="11" alt=""/></a></div> 6SN7 vacuum tube dual triode (1980s manufacture)</div> </div> </div> <p><a href="/web/20140817094520/http://en.wikipedia.org/wiki/File:EIA-8BD.png" class="image"><img alt="EIA-8BD.png" src="//web.archive.org/web/20140817094520im_/http://upload.wikimedia.org/wikipedia/en/4/4e/EIA-8BD.png" width="317" height="173" data-file-width="317" data-file-height="173"/></a></p> <p></p> <div id="toc" class="toc"> <div id="toctitle"> <h2>Contents</h2> </div> <ul> <li class="toclevel-1 tocsection-1"><a href="#History"><span class="tocnumber">1</span> <span class="toctext">History</span></a></li> <li class="toclevel-1 tocsection-2"><a href="#Related_Types"><span class="tocnumber">2</span> <span class="toctext">Related Types</span></a></li> <li class="toclevel-1 tocsection-3"><a href="#6J5"><span class="tocnumber">3</span> <span class="toctext">6J5</span></a></li> <li class="toclevel-1 tocsection-4"><a href="#Successors_to_the_6SN7"><span class="tocnumber">4</span> <span class="toctext">Successors to the 6SN7</span></a></li> <li class="toclevel-1 tocsection-5"><a href="#Usage"><span class="tocnumber">5</span> <span class="toctext">Usage</span></a></li> <li class="toclevel-1 tocsection-6"><a href="#See_also"><span class="tocnumber">6</span> <span class="toctext">See also</span></a></li> <li class="toclevel-1 tocsection-7"><a href="#References"><span class="tocnumber">7</span> <span class="toctext">References</span></a></li> <li class="toclevel-1 tocsection-8"><a href="#External_links"><span class="tocnumber">8</span> <span class="toctext">External links</span></a></li> </ul> </div> <p></p> <h2><span class="mw-headline" id="History">History</span><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/web/20140817094520/http://en.wikipedia.org/w/index.php?title=6SN7&action=edit&section=1" title="Edit section: History">edit</a><span class="mw-editsection-bracket">]</span></span></h2> <p>Originally released in 1939 it was officially registered in 1941 by RCA and Sylvania as the glass-cased <b>6SN7GT</b>, originally listed on page 235 of RCA's 1940 RC-14 Receiving Tube Manual, in the Recently Added section, as: <b>6SN7-GT</b>. Although the 6S-series tubes are often metal-cased, there was never a <i>metal-envelope</i> 6SN7 (there being no pin available to connect the metal shield); there were, however, a few glass-envelope tubes with a metal band, such as the <b>6SN7A</b> developed during World War II - slightly improved in some respects but the metal band was prone to splitting.<sup id="cite_ref-2" class="reference"><a href="#cite_note-2"><span>[</span>2<span>]</span></a></sup> Numerous variations on the <b>6SN7</b> type have been offered over the years, including:</p> <ul> <li><b>7N7</b> (Sylvania 1940, short-lived loktal-base version),</li> <li><b>1633</b> (RCA 1941, also for 26-V radios),</li> <li><b>12SX7</b> (RCA 1946, intended for use in 26-volt aircraft electronics),</li> <li><b>5692</b> (RCA 1948, a super-premium version - not exactly identical - with guaranteed 10,000 hour lifetime),</li> <li><b>6Н8С</b> (Soviet version, circa 1950, sometimes written: <b>6n8s</b>);</li> <li><b>6SN7 DDR</b>, <b>6Н8М</b>, <b>E1606</b> (=<b>CV278</b>), <b>OSW3129</b> versions with different/larger glass enevelopes;</li> <li><b>6042</b> (1951, another 1633 type), and</li> <li><b>6180</b> (1952)</li> <li><b>6SN7W</b> (1956; a more rugged military version, glass enevelope with metal band)<sup id="cite_ref-3" class="reference"><a href="#cite_note-3"><span>[</span>3<span>]</span></a></sup></li> </ul> <p>American military designator for the 6SN7GA was <b>VT-231</b>, and the British called it <b>CV1988</b>. European designations include the 1942 <b>ECC32</b> (not an exact equivalent), <b>13D2</b> and <b>B65</b>.</p> <p>The 6SN7 has a 6.3 V 600 mA heater/filament. The 12-volt 300 mA filament equivalent is the <b>12SN7GT</b> or <b>12SN7GTA</b>. The <b>14N7</b> is the Loktal version of the 12SN7GT. There was also a comparatively rare 8V <b>8SN7</b> for 450 mA series-string TV sets) and 25 Volt/0.15 Amp heater version: <b>25SN7GT</b>.</p> <h2><span class="mw-headline" id="Related_Types">Related Types</span><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/web/20140817094520/http://en.wikipedia.org/w/index.php?title=6SN7&action=edit&section=2" title="Edit section: Related Types">edit</a><span class="mw-editsection-bracket">]</span></span></h2> <p>The 1937 <b>6F8G</b><sup id="cite_ref-4" class="reference"><a href="#cite_note-4"><span>[</span>4<span>]</span></a></sup> was also an octal-based double triode with essentially the same characteristics as the 6SN7 (or two 6J5's), but in a 'Coke Bottle' large (Outline ST-12) glass envelope with a different pin arrangement and utilising a top cap connection for the first triode's grid (making pin 1 available for a metal shield).</p> <h2><span class="mw-headline" id="6J5">6J5</span><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/web/20140817094520/http://en.wikipedia.org/w/index.php?title=6SN7&action=edit&section=3" title="Edit section: 6J5">edit</a><span class="mw-editsection-bracket">]</span></span></h2> <p>The <b>6J5</b>, first registered in June 1937,<sup id="cite_ref-5" class="reference"><a href="#cite_note-5"><span>[</span>5<span>]</span></a></sup> and <b>6J5GT</b> (registered April 1938; British version <b>L63</b>) were octal single triodes with identical characteristics to one half of a 6SN7. Other equivalents to the 6J5 include:</p> <ul> <li><b>VT-94</b>, <b>6C2</b>, <b>6J5M</b>, <b>38565J</b>;</li> <li>military versions: <b>CV1933</b>, <b>10E/11448</b> and <b>CV1934</b>;</li> <li><a href="/web/20140817094520/http://en.wikipedia.org/wiki/Loktal" title="Loktal" class="mw-redirect">Loktal</a> base version: <b>7A4</b> (military name: <b>CV1770</b>), and</li> <li>12.6 V heater version: <b>12J5</b>.</li> </ul> <p>They in turn were successors to the 1935 RCA <b>6C5</b> and 1938 <b>6P5G</b>.<sup id="cite_ref-6" class="reference"><a href="#cite_note-6"><span>[</span>6<span>]</span></a></sup></p> <h2><span class="mw-headline" id="Successors_to_the_6SN7">Successors to the 6SN7</span><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/web/20140817094520/http://en.wikipedia.org/w/index.php?title=6SN7&action=edit&section=4" title="Edit section: Successors to the 6SN7">edit</a><span class="mw-editsection-bracket">]</span></span></h2> <p>The 1954 <b>6CG7</b><sup id="cite_ref-7" class="reference"><a href="#cite_note-7"><span>[</span>7<span>]</span></a></sup> and <b>6FQ7</b> are electrically equivalent to the 6SN7, with <a href="/web/20140817094520/http://en.wikipedia.org/wiki/Tube_socket#Noval_base" title="Tube socket">9-pin miniature ("Noval")</a> base (RCA, 1951), also made as an 8.4V 450mA series string heater type as the <b>8CG7</b>.</p> <p>The 1948 <b>ECC40</b> with <a href="/web/20140817094520/http://en.wikipedia.org/wiki/Tube_socket#Rimlock_base" title="Tube socket">Rimlock base</a> can also considered a successor to the 6SN7<sup id="cite_ref-8" class="reference"><a href="#cite_note-8"><span>[</span>8<span>]</span></a></sup> (but closer in characteristics to the ECC32). The 1946 miniature <a href="/web/20140817094520/http://en.wikipedia.org/wiki/12AU7" title="12AU7">12AU7</a>/<b>ECC82</b>, with similar, but not identical, electrical characteristics to the 6SN7 and ECC32, and a filament usable on either 6.3 or 12.6V supplies, was more widely used than the 6CG7/6FQ7.</p> <h2><span class="mw-headline" id="Usage">Usage</span><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/web/20140817094520/http://en.wikipedia.org/w/index.php?title=6SN7&action=edit&section=5" title="Edit section: Usage">edit</a><span class="mw-editsection-bracket">]</span></span></h2> <p>The 6SN7 was often used as an audio amplifier in the 1940-1955 period, usually in the driver stages of power amps. The designer of the famous <a href="/web/20140817094520/http://en.wikipedia.org/wiki/Williamson_amplifier" title="Williamson amplifier">Williamson amplifier</a>, one of the first true <a href="/web/20140817094520/http://en.wikipedia.org/wiki/High-fidelity" title="High-fidelity" class="mw-redirect">high-fidelity</a> designs, suggested use of the 6SN7 (or B65) in his 1949 revision since it was similar to the original circuit's <b>L63</b> (=6J5) British single triodes, four of which were used in each channel of his 1947 circuit.</p> <p>The 6SN7 was one of the most important components of the first programmable digital computer, the <a href="/web/20140817094520/http://en.wikipedia.org/wiki/ENIAC" title="ENIAC">ENIAC</a>, which contained several thousand. The <a href="/web/20140817094520/http://en.wikipedia.org/wiki/Semi_Automatic_Ground_Environment" title="Semi Automatic Ground Environment" class="mw-redirect">SAGE</a> computer systems used hundreds of 5692s as <a href="/web/20140817094520/http://en.wikipedia.org/wiki/Flip-flop_(electronics)" title="Flip-flop (electronics)">flip-flops</a>.</p> <p>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 <b>GE 6SN7GTA</b> (GE, 1950) had <a href="/web/20140817094520/http://en.wikipedia.org/wiki/Anode" title="Anode">anode</a> dissipation uprated to 5.0 watts. The 1954 GE 6SN7GTB also had controlled heater warmup time, better for <a href="/web/20140817094520/http://en.wikipedia.org/wiki/Series_and_parallel_circuits" title="Series and parallel circuits">series</a> heater strings.</p> <p>The 6SN7 was considered to be obsolete by the 1960s, replaced by the <a href="/web/20140817094520/http://en.wikipedia.org/wiki/12AU7" title="12AU7">12AU7</a>, and became almost unobtainable. With the introduction of <a href="/web/20140817094520/http://en.wikipedia.org/wiki/Semiconductor_electronics" title="Semiconductor electronics" class="mw-redirect">semiconductor electronics</a>, vacuum tubes of all types ceased to be manufactured by the major producers.</p> <p>A small demand for vacuum tubes in <a href="/web/20140817094520/http://en.wikipedia.org/wiki/Guitar_amplifier" title="Guitar amplifier">guitar amplifiers</a> 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 <b>6SL7</b>. As of 2012<sup class="plainlinks noprint asof-tag update" style="display:none;"><a class="external text" href="//web.archive.org/web/20140817094520/http://en.wikipedia.org/w/index.php?title=6SN7&action=edit">[update]</a></sup>, 6SN7s were manufactured in Russia and China under the old Soviet designator <b>6N8S</b>.</p> <h2><span class="mw-headline" id="See_also">See also</span><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/web/20140817094520/http://en.wikipedia.org/w/index.php?title=6SN7&action=edit&section=6" title="Edit section: See also">edit</a><span class="mw-editsection-bracket">]</span></span></h2> <ul> <li><a href="/web/20140817094520/http://en.wikipedia.org/wiki/List_of_vacuum_tubes" title="List of vacuum tubes">List of vacuum tubes</a></li> <li><a href="/web/20140817094520/http://en.wikipedia.org/wiki/12AT7" title="12AT7">12AT7</a></li> <li><a href="/web/20140817094520/http://en.wikipedia.org/wiki/12AU7" title="12AU7">12AU7</a></li> <li><a href="/web/20140817094520/http://en.wikipedia.org/wiki/12AX7" title="12AX7">12AX7</a></li> </ul> <h2><span class="mw-headline" id="References">References</span><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/web/20140817094520/http://en.wikipedia.org/w/index.php?title=6SN7&action=edit&section=7" title="Edit section: References">edit</a><span class="mw-editsection-bracket">]</span></span></h2> <div class="reflist" style="list-style-type: decimal;"> <ol class="references"> <li id="cite_note-1"><span class="mw-cite-backlink"><b><a href="#cite_ref-1">^</a></b></span> <span class="reference-text"><span class="citation web"><a rel="nofollow" class="external text" href="https://web.archive.org/web/20140817094520/http://www.head-fi.org/t/209782/the-6sn7-identification-guide">"The 6SN7 Identification Guide"</a><span class="reference-accessdate">. Retrieved 10 June 2014</span>.</span><span title="ctx_ver=Z39.88-2004&rfr_id=info%3Asid%2Fen.wikipedia.org%3A6SN7&rft.btitle=The+6SN7+Identification+Guide&rft.genre=book&rft_id=http%3A%2F%2Fwww.head-fi.org%2Ft%2F209782%2Fthe-6sn7-identification-guide&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook" class="Z3988"><span style="display:none;"> </span></span></span></li> <li id="cite_note-2"><span class="mw-cite-backlink"><b><a href="#cite_ref-2">^</a></b></span> <span class="reference-text"><span class="citation web"><a rel="nofollow" class="external text" href="https://web.archive.org/web/20140817094520/http://www.audioasylum.com/audio/tubes/messages/5/53488.html">"Re: What the hell is a 6SN7A?"</a>. <i>Tubes Asylum</i>.</span><span title="ctx_ver=Z39.88-2004&rfr_id=info%3Asid%2Fen.wikipedia.org%3A6SN7&rft.atitle=Re%3A+What+the+hell+is+a+6SN7A%3F&rft.genre=article&rft_id=http%3A%2F%2Fwww.audioasylum.com%2Faudio%2Ftubes%2Fmessages%2F5%2F53488.html&rft.jtitle=Tubes+Asylum&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal" class="Z3988"><span style="display:none;"> </span></span></span></li> <li id="cite_note-3"><span class="mw-cite-backlink"><b><a href="#cite_ref-3">^</a></b></span> <span class="reference-text"><span class="citation web"><a rel="nofollow" class="external text" href="https://web.archive.org/web/20140817094520/http://www.r-type.org/exhib/aad0076.htm">"6SN7W at the National Valve Museum"</a>.</span><span title="ctx_ver=Z39.88-2004&rfr_id=info%3Asid%2Fen.wikipedia.org%3A6SN7&rft.btitle=6SN7W+at+the+National+Valve+Museum&rft.genre=book&rft_id=http%3A%2F%2Fwww.r-type.org%2Fexhib%2Faad0076.htm&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook" class="Z3988"><span style="display:none;"> </span></span></span></li> <li id="cite_note-4"><span class="mw-cite-backlink"><b><a href="#cite_ref-4">^</a></b></span> <span class="reference-text"><span class="citation web"><a rel="nofollow" class="external text" href="https://web.archive.org/web/20140817094520/http://www.radiomuseum.org/tubes/tube_6f8g.html">"6F8G"</a><span class="reference-accessdate">. Retrieved 10 June 2014</span>.</span><span title="ctx_ver=Z39.88-2004&rfr_id=info%3Asid%2Fen.wikipedia.org%3A6SN7&rft.btitle=6F8G&rft.genre=book&rft_id=http%3A%2F%2Fwww.radiomuseum.org%2Ftubes%2Ftube_6f8g.html&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook" class="Z3988"><span style="display:none;"> </span></span></span></li> <li id="cite_note-5"><span class="mw-cite-backlink"><b><a href="#cite_ref-5">^</a></b></span> <span class="reference-text"><span class="citation web"><a rel="nofollow" class="external text" href="https://web.archive.org/web/20140817094520/http://www.radiomuseum.org/tubes/tube_6j5.html">"6J5"</a><span class="reference-accessdate">. Retrieved 10 June 2014</span>.</span><span title="ctx_ver=Z39.88-2004&rfr_id=info%3Asid%2Fen.wikipedia.org%3A6SN7&rft.btitle=6J5&rft.genre=book&rft_id=http%3A%2F%2Fwww.radiomuseum.org%2Ftubes%2Ftube_6j5.html&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook" class="Z3988"><span style="display:none;"> </span></span></span></li> <li id="cite_note-6"><span class="mw-cite-backlink"><b><a href="#cite_ref-6">^</a></b></span> <span class="reference-text"><span class="citation web"><a rel="nofollow" class="external text" href="https://web.archive.org/web/20140817094520/http://www.radiomuseum.org/tubes/tube_6j5.html">"6J5"</a><span class="reference-accessdate">. Retrieved 10 June 2014</span>.</span><span title="ctx_ver=Z39.88-2004&rfr_id=info%3Asid%2Fen.wikipedia.org%3A6SN7&rft.btitle=6J5&rft.genre=book&rft_id=http%3A%2F%2Fwww.radiomuseum.org%2Ftubes%2Ftube_6j5.html&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook" class="Z3988"><span style="display:none;"> </span></span></span></li> <li id="cite_note-7"><span class="mw-cite-backlink"><b><a href="#cite_ref-7">^</a></b></span> <span class="reference-text"><span class="citation web"><a rel="nofollow" class="external text" href="https://web.archive.org/web/20140817094520/http://www.radiomuseum.org/tubes/tube_6cg7.html">"6CG7"</a><span class="reference-accessdate">. Retrieved 10 June 2014</span>.</span><span title="ctx_ver=Z39.88-2004&rfr_id=info%3Asid%2Fen.wikipedia.org%3A6SN7&rft.btitle=6CG7&rft.genre=book&rft_id=http%3A%2F%2Fwww.radiomuseum.org%2Ftubes%2Ftube_6cg7.html&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook" class="Z3988"><span style="display:none;"> </span></span></span></li> <li id="cite_note-8"><span class="mw-cite-backlink"><b><a href="#cite_ref-8">^</a></b></span> <span class="reference-text"><span class="citation web"><a rel="nofollow" class="external text" href="https://web.archive.org/web/20140817094520/http://www.radiomuseum.org/tubes/tube_ecc40.html">"ECC40"</a><span class="reference-accessdate">. Retrieved 10 June 2014</span>.</span><span title="ctx_ver=Z39.88-2004&rfr_id=info%3Asid%2Fen.wikipedia.org%3A6SN7&rft.btitle=ECC40&rft.genre=book&rft_id=http%3A%2F%2Fwww.radiomuseum.org%2Ftubes%2Ftube_ecc40.html&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook" class="Z3988"><span style="display:none;"> </span></span></span></li> </ol> </div> <h2><span class="mw-headline" id="External_links">External links</span><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/web/20140817094520/http://en.wikipedia.org/w/index.php?title=6SN7&action=edit&section=8" title="Edit section: External links">edit</a><span class="mw-editsection-bracket">]</span></span></h2> <ul> <li><a rel="nofollow" class="external text" href="https://web.archive.org/web/20140817094520/http://tubecollectors.org/">The Tube Collectors Association</a></li> <li><a rel="nofollow" class="external text" href="https://web.archive.org/web/20140817094520/http://www.mif.pg.gda.pl/homepages/frank/sheets/082/6/6SN7.pdf">Datasheet on the 6SN7</a></li> <li><a href="/web/20140817094520/http://en.wikipedia.org/wiki/RCA" title="RCA">RCA</a> Receiving Tube Manual, RC-14, Harrison NJ, 1940</li> <li>RCA receiving Tube Manual, RC-29, harrison NJ, 1973</li> <li><a href="/web/20140817094520/http://en.wikipedia.org/wiki/Osram_Sylvania" title="Osram Sylvania">Sylvania</a> Technical Manual 14th edition (reprint), 2000</li> <li>GE Techni-Talk, Volume 6 number 5, October–November 1954</li> <li><a rel="nofollow" class="external text" href="https://web.archive.org/web/20140817094520/http://www.mif.pg.gda.pl/homepages/frank/sheets/093/6/6CG7.pdf">Datasheet on the 6CG7</a></li> <li><a rel="nofollow" class="external autonumber" href="https://web.archive.org/web/20140817094520/http://www.joeltunnah.com/JT_TUBELIBRARY.txt">[1]</a> SPICE MODEL</li> <li><a rel="nofollow" class="external text" href="https://web.archive.org/web/20140817094520/http://www.tubemaze.info/tag/6sn7/">Reviews of 6sn7 tubes.</a></li> </ul>   <noscript><img src="//web.archive.org/web/20140817094520im_/http://en.wikipedia.org/wiki/Special:CentralAutoLogin/start?type=1x1" alt="" title="" width="1" height="1" style="border: none; position: absolute;"/></noscript></div> <div class="printfooter"> Retrieved from "<a dir="ltr" href="https://web.archive.org/web/20140817094520/http://en.wikipedia.org/w/index.php?title=6SN7&oldid=612309102">http://en.wikipedia.org/w/index.php?title=6SN7&oldid=612309102</a>" </div> <div id="catlinks" class="catlinks"><div id="mw-normal-catlinks" class="mw-normal-catlinks"><a href="/web/20140817094520/http://en.wikipedia.org/wiki/Help:Category" title="Help:Category">Categories</a>: <ul><li><a href="/web/20140817094520/http://en.wikipedia.org/wiki/Category:Vacuum_tubes" title="Category:Vacuum tubes">Vacuum tubes</a></li><li><a href="/web/20140817094520/http://en.wikipedia.org/wiki/Category:Guitar_amplification_tubes" title="Category:Guitar amplification tubes">Guitar amplification tubes</a></li></ul></div><div id="mw-hidden-catlinks" class="mw-hidden-catlinks mw-hidden-cats-hidden">Hidden categories: <ul><li><a href="/web/20140817094520/http://en.wikipedia.org/wiki/Category:Articles_containing_potentially_dated_statements_from_2012" title="Category:Articles containing potentially dated statements from 2012">Articles containing potentially dated statements from 2012</a></li><li><a href="/web/20140817094520/http://en.wikipedia.org/wiki/Category:All_articles_containing_potentially_dated_statements" title="Category:All articles containing potentially dated statements">All articles containing potentially dated statements</a></li></ul></div></div> <div class="visualClear"></div> </div> </div> <div id="mw-navigation"> <h2>Navigation menu</h2> <div id="mw-head"> <div id="p-personal" role="navigation" class="" aria-labelledby="p-personal-label"> <h3 id="p-personal-label">Personal tools</h3> <ul> <li id="pt-createaccount"><a href="/web/20140817094520/http://en.wikipedia.org/w/index.php?title=Special:UserLogin&returnto=6SN7&type=signup">Create account</a></li><li id="pt-login"><a href="/web/20140817094520/http://en.wikipedia.org/w/index.php?title=Special:UserLogin&returnto=6SN7" title="You're encouraged to log in; however, it's not mandatory. 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