{"product_id":"12au7-ecc82-raytheon-matched-pair-long-black-plate-square-getter-tested-tubes-usa-57","title":"12AU7 \/ ECC82 RAYTHEON Matched Pair Long Black Plate Square Getter Tested Tubes USA '57","description":"\u003ch3\u003e\u003cstrong\u003e12AU7 \/ ECC82 RAYTHEON Matched Pair Long Black Plate Square Getter Tested Tubes USA '57\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cp\u003e\u003cstrong\u003eLow Noise \u0026amp; Microphonics –\u003cspan\u003e STRONG - Vintage American Raytheon Production\u003c\/span\u003e\u003c\/strong\u003e\u003c\/p\u003e\n\u003ch3\u003e\u003cstrong\u003eTest Results:\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cp\u003eTube tested on an \u003cstrong\u003eAMPLITREX AT-1000\u003c\/strong\u003e Tube Tester:\u003c\/p\u003e\n\u003cul\u003e\n\n\u003cli\u003e\n\n\u003cstrong\u003eTest Conditions:\u003c\/strong\u003e\u003cspan\u003e Va = 250V ; Vg = -8.5V\u003c\/span\u003e\n\n\u003c\/li\u003e\n\n\u003cli\u003e\n\n\u003cstrong\u003e100% Average:\u003c\/strong\u003e\u003cspan\u003e Gm = 2200 ; Ia = 10.5 mA\u003c\/span\u003e\n\n\u003c\/li\u003e\n\n\u003cli\u003e\n\n\u003cstrong\u003eTest Result:\u003c\/strong\u003e STRONG\u003c\/li\u003e\n\n\n\u003c\/ul\u003e\n\u003cp\u003e\u003cstrong\u003eTube #4:\u003c\/strong\u003e\u003c\/p\u003e\n\u003cul\u003e\n\n\u003cli\u003e\n\n\u003cstrong\u003eSection 1:\u003c\/strong\u003e Gm = 1700 ; Ia = 9.6 mA\u003c\/li\u003e\n\n\u003cli\u003e\n\n\u003cstrong\u003eSection 2:\u003c\/strong\u003e Gm = 1600 ; Ia = 8.8 mA\u003c\/li\u003e\n\n\n\u003c\/ul\u003e\n\u003cp\u003e\u003cstrong\u003eTube #1:\u003c\/strong\u003e\u003c\/p\u003e\n\u003cul\u003e\n\n\u003cli\u003e\n\n\u003cstrong\u003eSection 1:\u003c\/strong\u003e Gm = 1600 ; Ia = 7.4 mA\u003c\/li\u003e\n\n\u003cli\u003e\n\n\u003cstrong\u003eSection 2:\u003c\/strong\u003e Gm = 1800 ; Ia = 8.6 mA \u003c\/li\u003e\n\n\n\u003c\/ul\u003e\n\u003cdiv\u003e\u003cstrong\u003eAdditional tests performed:\u003c\/strong\u003e\u003c\/div\u003e\n\u003cul\u003e\n\n\u003cli\u003e\u003cspan\u003e\u003cstrong\u003eBurn-in \/ Stability Test:\u003c\/strong\u003e 48h – OK\u003c\/span\u003e\u003c\/li\u003e\n\n\u003cli\u003e\u003cspan\u003e\u003cstrong\u003eMicrophonics:\u003c\/strong\u003e Very Low. Tested and compliant for use in hi-fi equipment and guitar amplifiers, even in the most sensitive audio stages.\u003c\/span\u003e\u003c\/li\u003e\n\n\u003cli\u003e\n\n\u003cstrong\u003eNoise: \u003c\/strong\u003eLow and well-controlled. Quiet operation in hi-fi environments and musical amplifiers in the intended positions.\u003c\/li\u003e\n\n\u003cli\u003e\u003cspan\u003e\u003cstrong\u003eBalance:\u003c\/strong\u003e Good. The sections present a consistent balance, fully compatible with use in hi-fi environments and musical amplifiers, in all applications where absolute symmetry between sections is not required.\u003c\/span\u003e\u003c\/li\u003e\n\n\u003cli\u003e\u003cspan\u003e\u003cstrong\u003eEmission Quality:\u003c\/strong\u003e Strong – Strong and steady emission, suitable for any application.\u003c\/span\u003e\u003c\/li\u003e\n\n\u003cli\u003e\u003cspan\u003e\u003cstrong\u003eShort Circuits and GAS:\u003c\/strong\u003e Absent.\u003c\/span\u003e\u003c\/li\u003e\n\n\n\u003c\/ul\u003e\n\u003ch3\u003e\u003cstrong\u003eDescription:\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cp data-pm-slice=\"1 1 []\"\u003e\u003cspan\u003eA prized pair of \u003c\/span\u003e\u003cstrong\u003e\u003cspan\u003e12AU7 \/ ECC82 Raytheon tubes of American production\u003c\/span\u003e\u003c\/strong\u003e\u003cspan\u003e, manufactured in the \u003c\/span\u003e\u003cstrong\u003e\u003cspan\u003e23rd week of 1957\u003c\/span\u003e\u003c\/strong\u003e\u003cspan\u003e and characterized by the sought-after \u003c\/span\u003e\u003cstrong\u003e\u003cspan\u003eLong Black Plates and Square Getter\u003c\/span\u003e\u003c\/strong\u003e\u003cspan\u003e construction. The code \u003c\/span\u003e\u003cstrong\u003e\u003cspan\u003e280 57-23\u003c\/span\u003e\u003c\/strong\u003e\u003cspan\u003e identifies the Raytheon Manufacturing Company and precisely documents the origin and manufacturing period of both pieces.\u003c\/span\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cspan\u003eThe tubes form an \u003c\/span\u003e\u003cstrong\u003e\u003cspan\u003eAmplitrex Matched\u003c\/span\u003e\u003c\/strong\u003e\u003cspan\u003e pair selected primarily based on transconductance, the most significant parameter for matching these double triodes. Tube #4 has an average of \u003c\/span\u003e\u003cstrong\u003e\u003cspan\u003e1650 µmhos\u003c\/span\u003e\u003c\/strong\u003e\u003cspan\u003e, while Tube #1 reaches \u003c\/span\u003e\u003cstrong\u003e\u003cspan\u003e1700 µmhos\u003c\/span\u003e\u003c\/strong\u003e\u003cspan\u003e, with a difference of just \u003c\/span\u003e\u003cstrong\u003e\u003cspan\u003e3%\u003c\/span\u003e\u003c\/strong\u003e\u003cspan\u003e. The average plate currents are \u003c\/span\u003e\u003cstrong\u003e\u003cspan\u003e9.2 and 8.0 mA\u003c\/span\u003e\u003c\/strong\u003e\u003cspan\u003e respectively: values that are not perfectly identical, but compatible with a match intended for general audio use.\u003c\/span\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cspan\u003eThe internal balance is good overall. Tube #4 measures \u003c\/span\u003e\u003cstrong\u003e\u003cspan\u003e1700\/1600 µmhos\u003c\/span\u003e\u003c\/strong\u003e\u003cspan\u003e and \u003c\/span\u003e\u003cstrong\u003e\u003cspan\u003e9.6\/8.8 mA\u003c\/span\u003e\u003c\/strong\u003e\u003cspan\u003e, while Tube #1 reaches \u003c\/span\u003e\u003cstrong\u003e\u003cspan\u003e1600\/1800 µmhos\u003c\/span\u003e\u003c\/strong\u003e\u003cspan\u003e and \u003c\/span\u003e\u003cstrong\u003e\u003cspan\u003e7.4\/8.6 mA\u003c\/span\u003e\u003c\/strong\u003e\u003cspan\u003e. The sections therefore present a consistent response, even without representing a selection of absolute symmetry. The pair is suitable for preamplifiers, buffers, line stages, drivers, and musical instrument amplifiers, while for particularly critical phase inverter circuits, a selection with even more rigorously balanced sections is preferable.\u003c\/span\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cspan\u003eThe \u003c\/span\u003e\u003cstrong\u003e\u003cspan\u003e48-hour burn-in\u003c\/span\u003e\u003c\/strong\u003e\u003cspan\u003e confirmed operational stability, with no fluctuations, short circuits, or presence of gas. The \u003c\/span\u003e\u003cstrong\u003e\u003cspan\u003every low microphonics\u003c\/span\u003e\u003c\/strong\u003e\u003cspan\u003e and well-controlled noise are a significant strength, making these Raytheons suitable even for the most sensitive audio stages of compatible equipment.\u003c\/span\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cspan\u003eIn terms of sound, Raytheon Long Black Plates are appreciated for a \u003c\/span\u003e\u003cstrong\u003e\u003cspan\u003edynamic, natural, and full-bodied\u003c\/span\u003e\u003c\/strong\u003e\u003cspan\u003e reproduction, with a rich and well-articulated mid-range, solid low frequencies, and a defined high end without being harsh. In hi-fi systems, they offer musicality, good depth, and a stable soundstage; in guitar amplifiers, they ensure a responsive attack, control, and an authoritative character.\u003c\/span\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cspan\u003eA proposal of significant interest for those seeking an \u003c\/span\u003e\u003cstrong\u003e\u003cspan\u003eAmerican 1957 Raytheon pair\u003c\/span\u003e\u003c\/strong\u003e\u003cspan\u003e, with Long Black Plates, Square Getter, accurately matched transconductance, very low microphonics, and excellent cosmetic condition: two authentic vintage 12AU7\/ECC82s, individually tested and ready for use.\u003c\/span\u003e\u003c\/p\u003e\n\u003chr\u003e\n\u003ch3\u003e\u003cstrong\u003eConditions:\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cul\u003e\n\n\u003cli\u003e\n\n\u003cstrong\u003eConditions:\u003c\/strong\u003e\u003cspan\u003e Vintage Tubes - Tested and fully functional. Supplied in our custom box for optimal protection.\u003c\/span\u003e\u003cspan\u003e\u003cstrong\u003e\u003c\/strong\u003e\u003c\/span\u003e\n\n\u003c\/li\u003e\n\n\u003cli\u003e\n\n\u003cstrong\u003eCosmetic condition:\u003c\/strong\u003e Excellent – Markings well-preserved, minimal signs of age. See photos for details.\u003c\/li\u003e\n\n\u003cli\u003e\n\n\u003cstrong\u003eManufacturing Code:\u003c\/strong\u003e 280 57-23 → 280 indicates the manufacturer, Raytheon Mfg. Company, Newton 58, Mass. - 57-23 → RMA\/EIA Open Date Code → manufactured the 23rd week of 1957\u003c\/li\u003e\n\n\n\u003c\/ul\u003e\n\u003cp\u003e\u003ca href=\"https:\/\/vacuumtubestreasures.com\/blogs\/notizie\/perche-le-nostre-valvole-sono-diverse\" title=\"Find out why our tubes are different – the VTT protocol that improves sound, reliability, and lifespan\" rel=\"noopener\" target=\"_blank\"\u003e\u003cstrong\u003eFind out why our tubes are different →\u003c\/strong\u003e\u003c\/a\u003e\u003c\/p\u003e","brand":"RAYTHEON","offers":[{"title":"Default Title","offer_id":59387733934428,"sku":"03869L","price":280.0,"currency_code":"ILS","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0616\/3775\/5127\/files\/1_b12aedcc-8dd7-4df0-991e-cecf22091313.jpg?v=1791307899","url":"https:\/\/vacuumtubestreasures.com\/en-il\/products\/12au7-ecc82-raytheon-matched-pair-long-black-plate-square-getter-tested-tubes-usa-57","provider":"Vacuum Tubes Treasures","version":"1.0","type":"link"}