{"product_id":"12au7-ecc82-raytheon-matched-pair-long-black-plate-square-getter-tested-tubes-usa-59","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 \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 \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 #6:\u003c\/strong\u003e\u003c\/p\u003e\n\u003cul\u003e\n\n\u003cli\u003e\n\n\u003cstrong\u003eSection 1:\u003c\/strong\u003e Gm = 1800 ; Ia = 8.6 mA\u003c\/li\u003e\n\n\u003cli\u003e\n\n\u003cstrong\u003eSection 2:\u003c\/strong\u003e Gm = \u003cmeta charset=\"utf-8\"\u003e1800 ; Ia = 8.8 mA\u003c\/li\u003e\n\n\n\u003c\/ul\u003e\n\u003cp\u003e\u003cstrong\u003eTube #5:\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\"\u003e2000 ; Ia = 9.6 mA\u003c\/li\u003e\n\n\u003cli\u003e\n\n\u003cstrong\u003eSection 2:\u003c\/strong\u003e Gm = 1900 ; Ia = 9.6 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, including 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 settings and in musical amplifiers in the required positions.\u003c\/li\u003e\n\n\u003cli\u003e\u003cspan\u003e\u003cstrong\u003eBalance:\u003c\/strong\u003e Excellent - The sections are consistent and well-aligned, making the tube also suitable for use as a phase inverter in hi-fi and musical applications.\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 characterized by their sought-after \u003c\/span\u003e\u003cstrong\u003e\u003cspan\u003eLong Black Plate 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 have been matched based on their overall electrical performance. Tube #6 features an average transconductance of \u003c\/span\u003e\u003cstrong\u003e\u003cspan\u003e1800 µmhos\u003c\/span\u003e\u003c\/strong\u003e\u003cspan\u003e and an average anode current of \u003c\/span\u003e\u003cstrong\u003e\u003cspan\u003e8.7 mA\u003c\/span\u003e\u003c\/strong\u003e\u003cspan\u003e; Tube #5 reaches \u003c\/span\u003e\u003cstrong\u003e\u003cspan\u003e1950 µmhos\u003c\/span\u003e\u003c\/strong\u003e\u003cspan\u003e and \u003c\/span\u003e\u003cstrong\u003e\u003cspan\u003e9.6 mA\u003c\/span\u003e\u003c\/strong\u003e\u003cspan\u003e. The differences remain within approximately \u003c\/span\u003e\u003cstrong\u003e\u003cspan\u003e10%\u003c\/span\u003e\u003c\/strong\u003e\u003cspan\u003e on both parameters, allowing them to be offered as a matched pair for general audio use, without defining them as a precision-matched set.\u003c\/span\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cspan\u003eThe main strength is the \u003c\/span\u003e\u003cstrong\u003e\u003cspan\u003eexcellent internal balance\u003c\/span\u003e\u003c\/strong\u003e\u003cspan\u003e. Tube #6 measures \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\/8.8 mA\u003c\/span\u003e\u003c\/strong\u003e\u003cspan\u003e, while Tube #5 reaches \u003c\/span\u003e\u003cstrong\u003e\u003cspan\u003e2000\/1900 µmhos\u003c\/span\u003e\u003c\/strong\u003e\u003cspan\u003e with perfectly coincident currents of \u003c\/span\u003e\u003cstrong\u003e\u003cspan\u003e9.6\/9.6 mA\u003c\/span\u003e\u003c\/strong\u003e\u003cspan\u003e. This remarkable symmetry between the sections makes both tubes particularly interesting for use as a \u003c\/span\u003e\u003cstrong\u003e\u003cspan\u003ephase inverter\u003c\/span\u003e\u003c\/strong\u003e\u003cspan\u003e, as well as in compatible preamplifiers, buffers, line stages, and drivers.\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 regular 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 allow for use even in the most sensitive audio stages, both in hi-fi equipment and musical instrument amplifiers.\u003c\/span\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cspan\u003eSonically, 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 midrange, solid low frequencies, and a high end that is defined without being sharp. In hi-fi systems, they promote musicality, depth, and image stability; in guitar amplifiers, they ensure a responsive, controlled, and authoritative character.\u003c\/span\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cspan\u003eA highly interesting proposal for those seeking an \u003c\/span\u003e\u003cstrong\u003e\u003cspan\u003eAmerican Raytheon pair from the same lot\u003c\/span\u003e\u003c\/strong\u003e\u003cspan\u003e, with Long Black Plates, Square Getter, exceptionally balanced internal sections, very low microphonics, and excellent aesthetic condition: two authentic 1957 12AU7\/ECC82 tubes, tested individually 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 fully functional. Provided 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 – 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 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=\"Find out why our tubes are different – the VTT protocol that improves sound, reliability, and longevity\" 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":59421802266972,"sku":"03871L","price":913.0,"currency_code":"SEK","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0616\/3775\/5127\/files\/2_06bcdd27-c14e-414e-bcaf-ac0d12c5f1e8.jpg?v=1791563728","url":"https:\/\/vacuumtubestreasures.com\/en-se\/products\/12au7-ecc82-raytheon-matched-pair-long-black-plate-square-getter-tested-tubes-usa-59","provider":"Vacuum Tubes Treasures","version":"1.0","type":"link"}