{"product_id":"12au7-ecc82-raytheon-matched-pair-long-black-plate-square-getter-tested-tubes-usa-58","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\u003cspan\u003e \u003c\/span\u003e\u003cstrong\u003eAMPLITREX AT-1000\u003cspan\u003e \u003c\/span\u003e\u003c\/strong\u003eTube 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 \u003c\/span\u003eGm = 2200 ; Ia = 10.5 mA\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 #2:\u003c\/strong\u003e\u003c\/p\u003e\n\u003cul\u003e\n\n\u003cli\u003e\n\n\u003cstrong\u003eSection 1:\u003c\/strong\u003e Gm = 1700 ; Ia = 7.8 mA\u003c\/li\u003e\n\n\u003cli\u003e\n\n\u003cstrong\u003eSection 2:\u003c\/strong\u003e Gm = \u003cmeta charset=\"utf-8\"\u003e1800 ; Ia = 9.0 mA\u003c\/li\u003e\n\n\n\u003c\/ul\u003e\n\u003cp\u003e\u003cstrong\u003eTube #3:\u003c\/strong\u003e\u003c\/p\u003e\n\u003cul\u003e\n\n\u003cli\u003e\n\n\u003cstrong\u003eSection 1:\u003c\/strong\u003e Gm = \u003cmeta charset=\"utf-8\"\u003e1800 ; Ia = \u003cmeta charset=\"utf-8\"\u003e8.6 mA\u003c\/li\u003e\n\n\u003cli\u003e\n\n\u003cstrong\u003eSection 2:\u003c\/strong\u003e Gm = 1800 ; Ia = \u003cmeta charset=\"utf-8\"\u003e9.2 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 in musical amplifiers in the intended positions.\u003c\/li\u003e\n\n\u003cli\u003e\u003cspan\u003e\u003cstrong\u003eBalance:\u003c\/strong\u003e Good. The sections show a consistent balance, fully compatible with use in hi-fi 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\u003eAmerican-made 12AU7 \/ ECC82 Raytheon tubes\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 featuring 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 both the manufacturer and the production period of the two units.\u003c\/span\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cspan\u003eThe tubes form a particularly consistent \u003c\/span\u003e\u003cstrong\u003e\u003cspan\u003eAmplitrex Matched\u003c\/span\u003e\u003c\/strong\u003e\u003cspan\u003e pair. Tube #2 shows an average transconductance of \u003c\/span\u003e\u003cstrong\u003e\u003cspan\u003e1750 µmhos\u003c\/span\u003e\u003c\/strong\u003e\u003cspan\u003e, while Tube #3 reaches \u003c\/span\u003e\u003cstrong\u003e\u003cspan\u003e1800 µmhos\u003c\/span\u003e\u003c\/strong\u003e\u003cspan\u003e, with a difference of less than \u003c\/span\u003e\u003cstrong\u003e\u003cspan\u003e3%\u003c\/span\u003e\u003c\/strong\u003e\u003cspan\u003e. The average plate currents are also well-matched, at \u003c\/span\u003e\u003cstrong\u003e\u003cspan\u003e8.4 and 8.9 mA\u003c\/span\u003e\u003c\/strong\u003e\u003cspan\u003e respectively, confirming good operational consistency between the two units.\u003c\/span\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cspan\u003eThe internal balance is overall very convincing. Tube #2 measures \u003c\/span\u003e\u003cstrong\u003e\u003cspan\u003e1700\/1800 µmhos\u003c\/span\u003e\u003c\/strong\u003e\u003cspan\u003e and \u003c\/span\u003e\u003cstrong\u003e\u003cspan\u003e7.8\/9.0 mA\u003c\/span\u003e\u003c\/strong\u003e\u003cspan\u003e, while Tube #3 reaches \u003c\/span\u003e\u003cstrong\u003e\u003cspan\u003e1800\/1800 µmhos\u003c\/span\u003e\u003c\/strong\u003e\u003cspan\u003e and \u003c\/span\u003e\u003cstrong\u003e\u003cspan\u003e8.6\/9.2 mA\u003c\/span\u003e\u003c\/strong\u003e\u003cspan\u003e. The latter shows perfectly matching transconductance between the two sections; the former maintains a good balance, despite showing a more evident difference in plate current. The pair is therefore suitable for standard hi-fi and instrumental applications, while for circuits requiring absolute symmetry, a more rigorous selection 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 stable and steady operation, with no fluctuations, short circuits, or gas presence. The \u003c\/span\u003e\u003cstrong\u003e\u003cspan\u003every low microphonics\u003c\/span\u003e\u003c\/strong\u003e\u003cspan\u003e and well-controlled noise represent a significant strength, making these tubes suitable for preamplifiers, buffers, line stages, drivers, and particularly sensitive audio positions.\u003c\/span\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cspan\u003eIn terms of sound, Raytheon Long Black Plates are prized 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 midrange, solid low frequencies, and a defined high end that is never harsh. In hi-fi systems, they promote musicality, depth, and a stable soundstage; in musical instrument amplifiers, they ensure a responsive, controlled, and authoritative character.\u003c\/span\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cspan\u003eA proposal of considerable interest for those looking for a \u003c\/span\u003e\u003cstrong\u003e\u003cspan\u003ematching Raytheon American pair from the same lot\u003c\/span\u003e\u003c\/strong\u003e\u003cspan\u003e, with Long Black Plates, Square Getter, accurately matched transconductance, very low microphonics, and excellent aesthetic condition: two authentic 1957 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\u003eCondition:\u003c\/strong\u003e\u003cspan\u003e Vintage Tubes - Tested and perfectly 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\u003eAesthetic condition:\u003c\/strong\u003e Excellent – Lettering 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 in 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=\"Perché le nostre valvole sono diverse – il protocollo VTT che migliora suono, affidabilità e durata\" rel=\"noopener\" target=\"_blank\"\u003e\u003cstrong\u003eDiscover why our tubes are different →\u003c\/strong\u003e\u003c\/a\u003e\u003c\/p\u003e","brand":"RAYTHEON","offers":[{"title":"Default Title","offer_id":59411070976348,"sku":"03870L","price":79.9,"currency_code":"EUR","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0616\/3775\/5127\/files\/2_ba081b43-1e9d-4c6b-adbc-6a51b5de0b6b.jpg?v=1791485017","url":"https:\/\/vacuumtubestreasures.com\/en-lu\/products\/12au7-ecc82-raytheon-matched-pair-long-black-plate-square-getter-tested-tubes-usa-58","provider":"Vacuum Tubes Treasures","version":"1.0","type":"link"}