SherbyNet - /page/wikibook/entry.mu

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</style><table class="infobox"><tbody><tr><th colspan="2" class="infobox-above">12AX7</th></tr><tr><td colspan="2" class="infobox-image"><div class="infobox-caption" style="border-bottom:1px #aaa solid;">12AX7</div></td></tr><tr><th scope="row" class="infobox-label">Classification</th><td class="infobox-data">Dual triode</td></tr><tr><th scope="row" class="infobox-label">Service</th><td class="infobox-data"><a href="Class-A_amplifier" class="mw-redirect" title="Class-A amplifier">Class-A amplifier</a></td></tr><tr><th scope="row" class="infobox-label">Height</th><td class="infobox-data">2.2 in (56 mm)</td></tr><tr><th scope="row" class="infobox-label">Diameter</th><td class="infobox-data">0.8 in (20 mm)</td></tr><tr><th colspan="2" class="infobox-header" style="background:lightsteelblue;">Cathode</th></tr><tr><th scope="row" class="infobox-label">Cathode type</th><td class="infobox-data">Indirectly heated</td></tr><tr><th scope="row" class="infobox-label">Heater voltage</th><td class="infobox-data">12.6 V (series)<br>6.3 V (parallel)</td></tr><tr><th scope="row" class="infobox-label">Heater current</th><td class="infobox-data">150 mA (series)<br>300 mA (parallel)</td></tr><tr><th colspan="2" class="infobox-header" style="background:lightsteelblue;">Anode</th></tr><tr><th scope="row" class="infobox-label">Max dissipation Watts</th><td class="infobox-data">1 per section</td></tr><tr><th scope="row" class="infobox-label">Max voltage</th><td class="infobox-data">300 V</td></tr><tr><th colspan="2" class="infobox-header" style="background:lightsteelblue;">Socket connections</th></tr><tr><td colspan="2" class="infobox-full-data"><span class="mw-default-size" typeof="mw:File"></span></td></tr><tr><th colspan="2" class="infobox-header" style="background:lightsteelblue;">Typical <a href="Class-A_amplifier" class="mw-redirect" title="Class-A amplifier">class-A amplifier</a> operation</th></tr><tr><th scope="row" class="infobox-label">Amplification factor</th><td class="infobox-data">100</td></tr><tr><th scope="row" class="infobox-label">Anode voltage</th><td class="infobox-data">250 V</td></tr><tr><th scope="row" class="infobox-label">Anode current</th><td class="infobox-data">1.2 mA</td></tr><tr><th scope="row" class="infobox-label">Bias voltage</th><td class="infobox-data">−2 V</td></tr><tr><th scope="row" class="infobox-label">Anode resistance</th><td class="infobox-data">62.5 kΩ</td></tr><tr><th colspan="2" class="infobox-header" style="background:lightsteelblue;">References</th></tr><tr><td colspan="2" class="infobox-full-data"><a rel="nofollow" class="external text" href="https://drtube.com/datasheets/12ax7-sylvania1955.pdf">Sylvania 12AX7 datasheet</a></td></tr></tbody></table>

<p><b>12AX7</b> (also known as ECC83<sup id="cite_ref-1" class="reference"><a href="#cite_note-1"><span class="cite-bracket">[</span>1<span class="cite-bracket">]</span></a></sup>) is a miniature dual-<a href="Triode" title="Triode">triode</a> <a href="Vacuum_tube" title="Vacuum tube">vacuum tube</a> with high voltage <a href="Gain_(electronics)" title="Gain (electronics)">gain</a>. Developed around 1946 by <a href="RCA" title="RCA">RCA</a> engineers<sup id="cite_ref-vintage_2-0" class="reference"><a href="#cite_note-vintage-2"><span class="cite-bracket">[</span>2<span class="cite-bracket">]</span></a></sup> in <a href="Camden%2C_New_Jersey" title="Camden, New Jersey">Camden, New Jersey</a>, under developmental number A-4522, it was released for public sale under the 12AX7 identifier on September 15, 1947.

</p><p>The 12AX7 was originally intended as replacement for the 6SL7 family of dual-triode amplifier tubes for audio applications. As a popular choice for guitar tube amplifiers, its ongoing use in such equipment makes it one of the few small-signal vacuum tubes in continuous production since it was introduced.

</p>

<div class="mw-heading mw-heading2"><h2 id="History">History</h2></div>

<p>The 12AX7 is a twin triode basically composed of two of the triodes from a 6AV6, a double diode triode. The 6AV6 is a miniature repackaging (with just a single cathode) of the triode and twin diodes from the octal 6SQ7 (a double-diode triode used in AM radios), which itself is very similar to the older type 75 triode-diode dating from 1930.

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<div class="mw-heading mw-heading2"><h2 id="Application">Application</h2></div>

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<p>The 12AX7 is a high-gain (typical amplification factor 100), low-plate-current <a href="Triode" title="Triode">triode</a> best suited for low-level audio voltage amplification. In this role it is widely used for the preamplifier (input and mid-level) stages of audio amplifiers. It has relatively high <a href="Miller_effect" title="Miller effect">Miller</a> capacitance, making it unsuitable for radio-frequency use.

</p><p>Typically a 12AX7 triode is configured with a high-value plate resistor, 100 kohms in most guitar amps and 220 kΩ or more in high-fidelity equipment. Grid bias is most often provided by a cathode resistor. If the cathode resistor is unbypassed, negative feedback is introduced and each half of a 12AX7 provides a typical voltage gain of about 30; the amplification factor is basically twice the maximum stage gain, as the plate impedance must be matched. Thus half the voltage is across the tube at rest, half across the load resistor. The cathode resistor can be bypassed to reduce or eliminate AC negative feedback and thereby increase gain; maximum gain is about 60 times with a 100k plate load, and a center biased and bypassed cathode, and higher with a larger plate load.<sup id="cite_ref-3" class="reference"><a href="#cite_note-3"><span class="cite-bracket">[</span>3<span class="cite-bracket">]</span></a></sup>

</p><p><span class="mwe-math-element mwe-math-element-inline"><span class="mwe-math-mathml-inline mwe-math-mathml-a11y" style="display: none;"><math xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle A_{v}=\mu \times R_{tot}/(r_{P}+R_{tot}+(R_{K}\times (\mu +1))}">

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<annotation encoding="application/x-tex">{\displaystyle A_{v}=\mu \times R_{tot}/(r_{P}+R_{tot}+(R_{K}\times (\mu +1))}</annotation>

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</math></span><img src="./717caf0128f040e2031ce7bdd49d1d37f35c23d8.svg" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.838ex; width:43.659ex; height:2.843ex;" alt="{\displaystyle A_{v}=\mu \times R_{tot}/(r_{P}+R_{tot}+(R_{K}\times (\mu +1))}" loading="lazy"></span>

</p><p>Where <span class="mwe-math-element mwe-math-element-inline"><span class="mwe-math-mathml-inline mwe-math-mathml-a11y" style="display: none;"><math xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle A_{v}}">

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<annotation encoding="application/x-tex">{\displaystyle r_{P}}</annotation>

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</math></span><img src="./d3529d17c0061c3ae350efc5f69d81cc83c656eb.svg" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.671ex; width:2.515ex; height:2.009ex;" alt="{\displaystyle r_{P}}" loading="lazy"></span> is the internal plate resistance, <span class="mwe-math-element mwe-math-element-inline"><span class="mwe-math-mathml-inline mwe-math-mathml-a11y" style="display: none;"><math xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle R_{K}}">

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<annotation encoding="application/x-tex">{\displaystyle R_{K}}</annotation>

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</math></span><img src="./4a5e14b5e0a65388232008fe51554887f9bbc96d.svg" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.671ex; width:3.457ex; height:2.509ex;" alt="{\displaystyle R_{K}}" loading="lazy"></span> is the cathode resistor and <span class="mwe-math-element mwe-math-element-inline"><span class="mwe-math-mathml-inline mwe-math-mathml-a11y" style="display: none;"><math xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle R_{tot}}">

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</math></span><img src="./203847b56e637a9df11d99c36e336e87632dd566.svg" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.671ex; width:3.23ex; height:2.509ex;" alt="{\displaystyle R_{P}}" loading="lazy"></span> (external plate resistor) and <span class="mwe-math-element mwe-math-element-inline"><span class="mwe-math-mathml-inline mwe-math-mathml-a11y" style="display: none;"><math xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle R_{load}}">

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</math></span><img src="./0a3e75222fda1fe1281c7cda3c38159c3e61ae01.svg" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.671ex; width:5.013ex; height:2.509ex;" alt="{\displaystyle R_{load}}" loading="lazy"></span>. If the cathode resistor is bypassed, use <span class="mwe-math-element mwe-math-element-inline"><span class="mwe-math-mathml-inline mwe-math-mathml-a11y" style="display: none;"><math xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle R_{K}=0}">

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</p><p>The initial “12” in the designator implies a 12-volt heater requirement; however, the tube has a center-tapped heater so it can be used in either 6.3-V or 12.6-V heater circuits.

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<div class="mw-heading mw-heading2"><h2 id="Similar_twin-triode_designs">Similar twin-triode designs</h2></div>

<p>The 12AX7 is the most common member of what eventually became a large family of twin-triode vacuum tubes, manufactured all over the world, all sharing the same pinout (EIA 9A). Most use heaters which can be optionally wired in series (12.6V, 150 mA) or parallel (6.3V, 300 mA). Other tubes, which in some cases can be used interchangeably in an emergency or for different performance characteristics, include the <a href="12AT7" title="12AT7">12AT7</a>, <a href="12AU7" title="12AU7">12AU7</a>, <a href="12AV7" class="mw-redirect" title="12AV7">12AV7</a>, 12AY7, and the low-voltage 12U7, plus many four-digit EIA series dual triodes. They span a wide range of voltage gain and transconductance. Different versions of each were designed for enhanced ruggedness, low <a href="Microphonics" title="Microphonics">microphonics</a>, stability, lifespan, etc.

</p><p>Those other designs offer lower voltage gain (traded off for higher plate current) than the 12AX7 (which has a voltage gain or <span class="mwe-math-element mwe-math-element-inline"><span class="mwe-math-mathml-inline mwe-math-mathml-a11y" style="display: none;"><math xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle A_{v}}">

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</math></span><img src="./3cd85529417776f1ae43598d068b5ed468a4b704.svg" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.671ex; width:2.773ex; height:2.509ex;" alt="{\displaystyle A_{v}}" loading="lazy"></span> of 100), and are more suitable for high-frequency applications.

</p><p>Some American designs similar to the 12AX7:

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<ul><li>12AD7 (October 10, 1955 - 225mA heater - low hum)</li>

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</math></span><img src="./3cd85529417776f1ae43598d068b5ed468a4b704.svg" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.671ex; width:2.773ex; height:2.509ex;" alt="{\displaystyle A_{v}}" loading="lazy"></span> = 60)</li>

<li><a href="12AU7" title="12AU7">12AU7</a> (October 18, 1946, dual 6C4,<sup id="cite_ref-5" class="reference"><a href="#cite_note-5"><span class="cite-bracket">[</span>5<span class="cite-bracket">]</span></a></sup> <span class="mwe-math-element mwe-math-element-inline"><span class="mwe-math-mathml-inline mwe-math-mathml-a11y" style="display: none;"><math xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle A_{v}}">

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</math></span><img src="./3cd85529417776f1ae43598d068b5ed468a4b704.svg" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.671ex; width:2.773ex; height:2.509ex;" alt="{\displaystyle A_{v}}" loading="lazy"></span> = 17-20)</li>

<li>12AV7 (February 14, 1950 - dual 6BC4, <span class="mwe-math-element mwe-math-element-inline"><span class="mwe-math-mathml-inline mwe-math-mathml-a11y" style="display: none;"><math xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle A_{v}}">

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</math></span><img src="./3cd85529417776f1ae43598d068b5ed468a4b704.svg" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.671ex; width:2.773ex; height:2.509ex;" alt="{\displaystyle A_{v}}" loading="lazy"></span> = 37-41)</li>

<li><b>12AX7</b> (September 15, 1947 - dual 6DR4, also like octal 6SL7, <span class="mwe-math-element mwe-math-element-inline"><span class="mwe-math-mathml-inline mwe-math-mathml-a11y" style="display: none;"><math xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle A_{v}}">

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</math></span><img src="./3cd85529417776f1ae43598d068b5ed468a4b704.svg" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.671ex; width:2.773ex; height:2.509ex;" alt="{\displaystyle A_{v}}" loading="lazy"></span> = 100) dual 12AV6 (6AV6)</li>

<li>12AY7 (December 7, 1948 - <span class="mwe-math-element mwe-math-element-inline"><span class="mwe-math-mathml-inline mwe-math-mathml-a11y" style="display: none;"><math xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle A_{v}}">

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</math></span><img src="./3cd85529417776f1ae43598d068b5ed468a4b704.svg" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.671ex; width:2.773ex; height:2.509ex;" alt="{\displaystyle A_{v}}" loading="lazy"></span> = 44, for audio preamp use)<sup id="cite_ref-6" class="reference"><a href="#cite_note-6"><span class="cite-bracket">[</span>6<span class="cite-bracket">]</span></a></sup></li>

<li>12AZ7 (March 2, 1951 - 225mA heater, <span class="mwe-math-element mwe-math-element-inline"><span class="mwe-math-mathml-inline mwe-math-mathml-a11y" style="display: none;"><math xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle A_{v}}">

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</math></span><img src="./3cd85529417776f1ae43598d068b5ed468a4b704.svg" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.671ex; width:2.773ex; height:2.509ex;" alt="{\displaystyle A_{v}}" loading="lazy"></span> = 60)</li>

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</math></span><img src="./3cd85529417776f1ae43598d068b5ed468a4b704.svg" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.671ex; width:2.773ex; height:2.509ex;" alt="{\displaystyle A_{v}}" loading="lazy"></span> = 100, low microphonics)</li>

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</math></span><img src="./3cd85529417776f1ae43598d068b5ed468a4b704.svg" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.671ex; width:2.773ex; height:2.509ex;" alt="{\displaystyle A_{v}}" loading="lazy"></span> = 100)</li>

<li>12DW7 <sup id="cite_ref-7" class="reference"><a href="#cite_note-7"><span class="cite-bracket">[</span>7<span class="cite-bracket">]</span></a></sup>(First triode: <span class="mwe-math-element mwe-math-element-inline"><span class="mwe-math-mathml-inline mwe-math-mathml-a11y" style="display: none;"><math xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle A_{v}}">

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<annotation encoding="application/x-tex">{\displaystyle A_{v}}</annotation>

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</math></span><img src="./3cd85529417776f1ae43598d068b5ed468a4b704.svg" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.671ex; width:2.773ex; height:2.509ex;" alt="{\displaystyle A_{v}}" loading="lazy"></span> = 100, Second triode: <span class="mwe-math-element mwe-math-element-inline"><span class="mwe-math-mathml-inline mwe-math-mathml-a11y" style="display: none;"><math xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle A_{v}}">

<msub>

</mrow>

</msub>

</mstyle>

</mrow>

<annotation encoding="application/x-tex">{\displaystyle A_{v}}</annotation>

</semantics>

</math></span><img src="./3cd85529417776f1ae43598d068b5ed468a4b704.svg" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.671ex; width:2.773ex; height:2.509ex;" alt="{\displaystyle A_{v}}" loading="lazy"></span> = 17)</li>

<msub>

</mrow>

</msub>

</mstyle>

</mrow>

<annotation encoding="application/x-tex">{\displaystyle A_{v}}</annotation>

</semantics>

</math></span><img src="./3cd85529417776f1ae43598d068b5ed468a4b704.svg" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.671ex; width:2.773ex; height:2.509ex;" alt="{\displaystyle A_{v}}" loading="lazy"></span> = 20, for use in automotive radios on 12-volt plate supply)</li></ul>

<p>Although commonly known in Europe by its <a href="Mullard%E2%80%93Philips_tube_designation" title="Mullard–Philips tube designation">Mullard–Philips tube designation</a> of ECC83, other European variations also exist including the low-<a href="Signal_noise" class="mw-redirect" title="Signal noise">noise</a> versions 12AX7A, 12AD7, 6681, 7025, and 7729; European versions B339, B759, CV492, CV4004, CV8156, CV8222, ECC803, ECC803S, E2164, and M8137; and the lower-gain low-noise versions 5751 and 6851, intended for avionics equipment.

</p><p>In European usage special-quality valves of some sort were often indicated by exchanging letters and digits in the name: the E83CC was a special-quality ECC83.

In the US a "W" in the designation, as in 12AX7WA, designates the tube as complying with military grade, higher reliability specifications.

</p><p>The 'E' in the European designation classifies this as having a 6.3 volt heater, whereas the American designation of 12AX7 classifies it as having a 12.6 volt heater. It can, of course, be wired for operation off either voltage.

</p>

<div class="mw-heading mw-heading2"><h2 id="Manufacturers">Manufacturers</h2></div>

<p>As of 2022 versions of the 12AX7/ECC83 are available from the following manufacturers:

</p>

<ul><li>In <a href="Russia" title="Russia">Russia</a>: <a href="Sovtek" title="Sovtek">New Sensor</a>, which produces tubes under the <a href="Sovtek" title="Sovtek">Sovtek</a>, <a href="Electro-Harmonix" title="Electro-Harmonix">Electro-Harmonix</a>, Svetlana, <a href="Tung-Sol" title="Tung-Sol">Tung-Sol</a>, and <a href="Mullard" title="Mullard">Mullard</a> brands</li>

<li>In <a href="Slovakia" title="Slovakia">Slovakia</a>: <a href="JJ_Electronic" title="JJ Electronic">JJ Electronic</a> (annual production of approximately two million units) [citation needed]</li>

<li>In <a href="China" title="China">China</a>: Hengyang Electronics, Tubes<sup id="cite_ref-8" class="reference"><a href="#cite_note-8"><span class="cite-bracket">[</span>8<span class="cite-bracket">]</span></a></sup> sold under Psvane and TAD<sup id="cite_ref-9" class="reference"><a href="#cite_note-9"><span class="cite-bracket">[</span>9<span class="cite-bracket">]</span></a></sup> brand names. Company owns its independent manufacturing facility in Southern China<sup id="cite_ref-10" class="reference"><a href="#cite_note-10"><span class="cite-bracket">[</span>10<span class="cite-bracket">]</span></a></sup> (former Guiguang tube factory)<sup id="cite_ref-11" class="reference"><a href="#cite_note-11"><span class="cite-bracket">[</span>11<span class="cite-bracket">]</span></a></sup> and recently they acquired former small signal tube manufacturing line from Tianjin Quanzheng factory (TJ Full Music) <sup id="cite_ref-12" class="reference"><a href="#cite_note-12"><span class="cite-bracket">[</span>12<span class="cite-bracket">]</span></a></sup></li></ul>

<div class="mw-heading mw-heading2"><h2 id="Gallery">Gallery</h2></div>

<div class="gallerytext">Electro-Harmonix 12AX7EH</div>

</li>

<div class="gallerytext">Various brands of 12AX7, with measuring tape to indicate size</div>

</li>

<div class="gallerytext">Tungsram ECC83 during operation</div>

</li>

<div class="gallerytext">Philips JAN 12AX7WA (Joint Army Navy)</div>

</li>

</ul>

<ul><li><a href="List_of_vacuum_tubes" title="List of vacuum tubes">List of vacuum tubes</a></li></ul>

<div class="mw-heading mw-heading2"><h2 id="References">References</h2></div>

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</style><cite class="citation web cs1"><a rel="nofollow" class="external text" href="https://www.thetubestore.com/preamp-tubes/12ax7-ecc83-tube-types">"www.thetubestore.com - 12AX7 / ECC83 Tube Types"</a>.</cite></span>

</li>

<li id="cite_note-vintage-2"><span class="mw-cite-backlink"><b><a href="#cite_ref-vintage_2-0">^</a></b></span> <span class="reference-text"><cite id="CITEREFJung2010" class="citation journal cs1">Jung, David (September 2010). "Draw! A 12AX7 'Shootout'". <i><a href="Vintage_Guitar_(magazine)" title="Vintage Guitar (magazine)">Vintage Guitar</a></i>: 114.</cite></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"><cite class="citation web cs1"><a rel="nofollow" class="external text" href="https://www.ampbooks.com/mobile/amplifier-calculators/output-impedance/calculator/">"Preamp Gain and Output Impedance Calculator"</a>.</cite></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">killerrig.com,<cite class="citation web cs1"><a rel="nofollow" class="external text" href="https://killerrig.com/12ax7-vs-12at7/">"12AX7 vs 12AT7 Tube Types"</a>. 13 April 2022.</cite></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"><cite class="citation web cs1"><a rel="nofollow" class="external text" href="https://www.thetubestore.com/preamp-tubes/6c4-m8080-tube-types">"www.thetubestore.com - Tubes with part numbers beginning with 6C4 - M8080 Tube"</a>. <i>www.thetubestore.com</i>.</cite></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"><cite class="citation web cs1"><a rel="nofollow" class="external text" href="https://www.thetubestore.com/preamp-tubes/12ay7-6072-tube-types">"www.thetubestore.com - Tubes with part numbers beginning with 12AY7 - 6072 Tube"</a>. <i>www.thetubestore.com</i>.</cite></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"><cite class="citation web cs1"><a rel="nofollow" class="external text" href="https://www.thetubestore.com/preamp-tubes/12dw7-7247-tube-types">"www.thetubestore.com - Tubes with part numbers beginning with 12DW7 - 7247 Tube"</a>. <i>www.thetubestore.com</i>.</cite></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">Classic series ECC83,<cite class="citation web cs1"><a rel="nofollow" class="external text" href="http://www.psvane.com/hifixl/714.html">"Changsha Hengyang Electronics Co., Ltd"</a>.</cite></span>

</li>

<li id="cite_note-9"><span class="mw-cite-backlink"><b><a href="#cite_ref-9">^</a></b></span> <span class="reference-text">Sales network,<cite class="citation web cs1"><a rel="nofollow" class="external text" href="http://www.psvane.com/en/salesnetwork.html">"Changsha Hengyang Electronics Co., Ltd"</a>.</cite></span>

</li>

<li id="cite_note-10"><span class="mw-cite-backlink"><b><a href="#cite_ref-10">^</a></b></span> <span class="reference-text">Rachel Zhang,<cite class="citation web cs1"><a rel="nofollow" class="external text" href="https://premiumvacuumtubes.com/who-is-psvane/">"Who is Psvane?"</a>.</cite></span>

</li>

<li id="cite_note-11"><span class="mw-cite-backlink"><b><a href="#cite_ref-11">^</a></b></span> <span class="reference-text">Rachel Zhang,<cite class="citation web cs1"><a rel="nofollow" class="external text" href="https://premiumvacuumtubes.com/who-was-guiguang/">"Who was GuiGuang"</a>.</cite></span>

</li>

<li id="cite_note-12"><span class="mw-cite-backlink"><b><a href="#cite_ref-12">^</a></b></span> <span class="reference-text">About Linlai Team,<cite class="citation web cs1"><a rel="nofollow" class="external text" href="https://www.linlaiglobal.com/">"LINLAI Global"</a>.</cite><cite class="citation web cs1"><a rel="nofollow" class="external text" href="http://www.linlaitube.com/en/">"Changsha Qiangsheng Light Power Co., Ltd"</a>.</cite></span>

</li>

</ol></div></div>

<div class="mw-heading mw-heading2"><h2 id="External_links">External links</h2></div>

<ul><li><a rel="nofollow" class="external text" href="http://tdsl.duncanamps.com/show.php?des=12AX7">Duncan's Amps TDSL.</a></li>

<li><a rel="nofollow" class="external text" href="https://web.archive.org/web/20180412193231/http://tubedata.milbert.com/sheets11.html">Several tube datasheets.</a></li>

<li><a rel="nofollow" class="external text" href="http://www.tubemaze.info/tag/12ax7/">Reviews of 12ax7 tubes.</a></li>

<li><a rel="nofollow" class="external text" href="https://www.jj-electronic.com/ecc83s-12ax7-7025">12AX7/ECC83 page</a> (with <a rel="nofollow" class="external text" href="https://www.jj-electronic.com/images/stories/product/preamplifying_tubes/pdf/ecc83s.pdf">datasheet</a>) at <a rel="nofollow" class="external text" href="https://www.jj-electronic.com/">JJ Electronic</a></li></ul></div><div><div class="zim-footer">

This article is issued from <a class="external text" title="Last edited on 2025-05-20" href="https://en.wikipedia.org/wiki/?title=12AX7&oldid=1291299759">Wikipedia</a>. The text is available under <a class="external text" href="https://creativecommons.org/licenses/by-sa/4.0/deed.en">Creative Commons Attribution-Share Alike 4.0</a> unless otherwise noted. Additional terms may apply for the media files.

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