{"product_id":"6sn7gtb-nos-sylvania-chrome-top-green-dot-tested-tube-black-plates-usa-1947","title":"6SN7GTB NOS SYLVANIA CHROME TOP Green Dot Tested Tube Black Plates USA '50s","description":"\u003cp\u003e\u003cstrong\u003e6SN7 GTB NOS SYLVANIA CHROME TOP Green Dot Black Plates Tested Tube Made in USA '57\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp data-end=\"817\" data-start=\"245\"\u003e\u003cspan data-end=\"290\" data-start=\"248\"\u003eThe\u003c\/span\u003e \u003cstrong data-end=\"303\" data-start=\"295\"\u003e1957\u003c\/strong\u003e \u003cstrong data-end=\"290\" data-start=\"248\"\u003eSylvania 6SN7 GTB\u003c\/strong\u003e , with \u003cstrong data-end=\"325\" data-start=\"309\"\u003eblack plates\u003c\/strong\u003e , \u003cstrong data-end=\"342\" data-start=\"327\"\u003echrome top\u003c\/strong\u003e , and \u003cstrong data-end=\"357\" data-start=\"344\"\u003egreen dot\u003c\/strong\u003e selector, represents one of the finest and most consistent NOS configurations in postwar American production. The green dot was a factory-applied marking by Sylvania to identify tubes selected for low noise and microphony, intended for critical military, professional, and high-end audio applications. The build quality of this generation makes it an excellent choice where \u003cstrong data-end=\"785\" data-start=\"726\"\u003etonal uniformity, quietness, and natural musicality\u003c\/strong\u003e are essential requirements.\u003c\/p\u003e\n\u003cp data-end=\"1000\" data-start=\"819\"\u003eThese valves are distinguished by a \u003cstrong data-end=\"895\" data-start=\"857\"\u003etransparent and three-dimensional voice\u003c\/strong\u003e , with a \u003cstrong data-end=\"936\" data-start=\"914\"\u003eneutral but musical\u003c\/strong\u003e character, capable of enhancing the microdynamics without forced colorations.\u003c\/p\u003e\n\u003cp data-end=\"1270\" data-start=\"1007\"\u003e\u003cstrong data-end=\"1016\" data-start=\"1007\"\u003eBass\u003c\/strong\u003e : tight and well-defined. The low range is \u003cstrong data-end=\"1100\" data-start=\"1056\"\u003earticulated, dry, and free of bloat\u003c\/strong\u003e , offering a \u003cstrong data-end=\"1154\" data-start=\"1129\"\u003econtrolled and stable\u003c\/strong\u003e harmonic foundation. Perfect for maintaining \u003cstrong data-end=\"1205\" data-start=\"1179\"\u003eclarity and precision\u003c\/strong\u003e in the lower registers, even in complex passages.\u003c\/p\u003e\n\u003cp data-end=\"1546\" data-start=\"1272\"\u003e\u003cstrong data-end=\"1280\" data-start=\"1272\"\u003eMids\u003c\/strong\u003e : Clear and natural. The midrange is \u003cstrong data-end=\"1357\" data-start=\"1321\"\u003ebalanced and free of artifacts\u003c\/strong\u003e , with \u003cstrong data-end=\"1384\" data-start=\"1363\"\u003ewell-centered vocals\u003c\/strong\u003e and a \u003cstrong data-end=\"1435\" data-start=\"1396\"\u003erealistic rendition of acoustic instruments\u003c\/strong\u003e . There is no artificial emphasis, but a \u003cstrong data-end=\"1497\" data-start=\"1473\"\u003econsistent transparency\u003c\/strong\u003e that facilitates deep and engaging listening.\u003c\/p\u003e\n\u003cp data-end=\"1768\" data-start=\"1548\"\u003e\u003cstrong data-end=\"1556\" data-start=\"1548\"\u003eHighs\u003c\/strong\u003e : Fine and non-fatiguing. The high range is \u003cstrong data-end=\"1627\" data-start=\"1598\"\u003edelicate, extended and airy\u003c\/strong\u003e , with a \u003cstrong data-end=\"1662\" data-start=\"1637\"\u003ediscreet brilliance\u003c\/strong\u003e and \u003cstrong data-end=\"1716\" data-start=\"1668\"\u003edetail well integrated into the musical fabric\u003c\/strong\u003e . Excellent for long listening sessions without fatigue.\u003c\/p\u003e\n\u003cp data-end=\"2053\" data-start=\"1770\"\u003e\u003cstrong data-end=\"1782\" data-start=\"1770\"\u003eDynamics\u003c\/strong\u003e : Fluid and modulated. The dynamic response is \u003cstrong data-end=\"1841\" data-start=\"1826\"\u003eprogressive\u003c\/strong\u003e , capable of \u003cstrong data-end=\"1900\" data-start=\"1864\"\u003enaturally reproducing minimal nuances\u003c\/strong\u003e , but also of sustaining \u003cstrong data-end=\"1945\" data-start=\"1924\"\u003eenergetic passages\u003c\/strong\u003e without stiffening. The valves react \u003cstrong data-end=\"2020\" data-start=\"1995\"\u003equickly but in a controlled\u003c\/strong\u003e manner, ensuring constant musicality.\u003c\/p\u003e\n\u003cp data-end=\"2341\" data-start=\"2055\"\u003e\u003cstrong data-end=\"2069\" data-start=\"2055\"\u003eSoundstage\u003c\/strong\u003e : Wide and stable. The soundstage is \u003cstrong data-end=\"2126\" data-start=\"2106\"\u003ewide and deep\u003c\/strong\u003e , with \u003cstrong data-end=\"2173\" data-start=\"2132\"\u003eexcellent instrument placement\u003c\/strong\u003e and \u003cstrong data-end=\"2208\" data-start=\"2180\"\u003ecoherent layering\u003c\/strong\u003e . The \u003cstrong\u003eprecision of the stereo image\u003c\/strong\u003e benefits from the electrical stability and constructional coherence typical of this Sylvania production.\u003c\/p\u003e\n\u003cp data-end=\"2713\" data-start=\"2348\"\u003e🎧 \u003cstrong data-end=\"2398\" data-start=\"2351\"\u003eUse in Hi-Fi Stereo Amplifiers\u003c\/strong\u003e\u003cbr data-end=\"2401\" data-start=\"2398\"\u003e\u003cmeta charset=\"utf-8\"\u003e An ideal choice for high-end preamps and driver stages, the \u003cstrong data-start=\"1768\" data-end=\"1796\"\u003e6SN7 Sylvania Chrome Top\u003c\/strong\u003e is renowned for its ability to combine transparency and warmth, offering a perfect balance between detail and musicality, making extended listening sessions consistently enjoyable.\u003cbr\u003e\u003c\/p\u003e\n\u003cp data-end=\"3044\" data-start=\"2715\"\u003e🎸 \u003cstrong data-end=\"2756\" data-start=\"2718\"\u003eUse in Instrument Amplifiers\u003c\/strong\u003e\u003cbr data-end=\"2759\" data-start=\"2756\"\u003e\u003cmeta charset=\"utf-8\"\u003e It's also highly regarded in boutique and vintage guitar amplifiers, where it delivers a rounded, harmonious, and natural sound. Its smooth yet detailed output makes it ideal for blues, jazz, and classic rock.\u003cbr\u003e\u003c\/p\u003e\n\u003cp data-end=\"3436\" data-start=\"3046\"\u003e🎯 \u003cstrong data-end=\"3081\" data-start=\"3049\"\u003eNote for audiophiles and technicians\u003c\/strong\u003e\u003cbr data-end=\"3084\" data-start=\"3081\"\u003e\u003cmeta charset=\"utf-8\"\u003e The 1957 \u003cstrong data-start=\"2266\" data-end=\"2321\"\u003e6SN7 GTB Sylvania Chrome Top Green Dot Black Plates\u003c\/strong\u003e is one of the most sought after variations of this iconic tube. \u003cbr data-start=\"2392\" data-end=\"2395\"\u003eIt combines the military\/industrial construction solidity of the time with the tonal refinement that made Sylvania a legendary name among audiophiles and collectors.\u003cbr data-start=\"2556\" data-end=\"2559\"\u003eA rare opportunity to own not only a tested NOS tube, but a true fragment of \u003cstrong data-start=\"2653\" data-end=\"2681\"\u003eauthentic American voice\u003c\/strong\u003e .\u003c\/p\u003e\n\u003chr\u003e\n\u003cp data-end=\"3436\" data-start=\"3046\"\u003e\u003cstrong\u003eTest Results:\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eValves tested on \u003cstrong\u003eAmplitrex AT-1000\u003c\/strong\u003e Tube tester:\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003e\u003cstrong\u003eTest Conditions:\u003c\/strong\u003e Va = 250V, Vg = -8V\u003c\/li\u003e\n\u003cli\u003e\u003cstrong\u003eAverage 100%\u003c\/strong\u003e \u003cstrong\u003eGm = 2600 ; Ia = 9.0 mA\u003c\/strong\u003e\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp\u003e\u003cstrong\u003eValve:\u003c\/strong\u003e\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003eSection 1: Gm = 2500 ; Ia = 7.4 mA\u003c\/li\u003e\n\u003cli\u003eSection 2: Gm = 2400 ; Ia = 7.4 mA\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cdiv\u003e\u003cstrong\u003eAdditional Tests Performed:\u003c\/strong\u003e\u003c\/div\u003e\n\u003cul\u003e\n\u003cli\u003e\u003cspan\u003e\u003cstrong\u003eMicrophonics:\u003c\/strong\u003e Low Noise \u0026amp; Microphonics – Tested and compliant for use in hi-fi systems and guitar amplifiers.\u003c\/span\u003e\u003c\/li\u003e\n\u003cli\u003e\u003cspan\u003e\u003cstrong\u003eOutput Quality:\u003c\/strong\u003e Excellent – Very strong and stable output, no fluctuations.\u003c\/span\u003e\u003c\/li\u003e\n\u003cli\u003e\u003cspan\u003e\u003cstrong\u003eShort circuits and GAS:\u003c\/strong\u003e Absent.\u003c\/span\u003e\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003chr\u003e\n\u003ch3\u003e\u003cstrong\u003eConditions:\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003e\u003cstrong\u003eCondition:\u003c\/strong\u003e NOS - New Old Stock - Tested and working - Supplied in our custom box for optimal protection.\u003cstrong\u003e\u003cbr\u003e\u003c\/strong\u003e\u003c\/li\u003e\n\u003cli\u003e\u003cstrong\u003eFunctionality:\u003c\/strong\u003e Fully functional.\u003cstrong\u003e\u003cbr\u003e\u003c\/strong\u003e\u003c\/li\u003e\n\u003cli\u003e\u003cstrong\u003eCosmetic condition:\u003c\/strong\u003e \u003cspan\u003eExcellent – Excellently preserved lettering, minimal signs of wear. See photos for details.\u003c\/span\u003e\u003cstrong\u003e\u003cbr\u003e\u003c\/strong\u003e \u003cstrong\u003eManufacturing Code:\u003cspan\u003e\u0026nbsp;\u003c\/span\u003e\u003c\/strong\u003e388 744 - Made in SYLVANIA USA - \u003cstrong data-end=\"349\" data-start=\"336\"\u003e388\u003c\/strong\u003e\u003cspan\u003e\u0026nbsp;\u003c\/span\u003e→ EIA code of the client (Modern Electronic Company Inc., New York 11, NY ) -\u003cspan\u003e\u0026nbsp;\u003c\/span\u003e\u003cstrong data-end=\"317\" data-start=\"310\"\u003e744\u003c\/strong\u003e\u003cspan\u003e\u0026nbsp;\u003c\/span\u003e→ 44th week of 1957\u003cmeta charset=\"utf-8\"\u003e\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp\u003e\u003cmeta charset=\"utf-8\"\u003e \u003ca rel=\"noopener\" title=\"Why our tubes are different – the VTT protocol that improves sound, reliability and durability\" href=\"https:\/\/vacuumtubestreasures.com\/blogs\/notizie\/perche-le-nostre-valvole-sono-diverse\" target=\"_blank\"\u003e\u003cstrong\u003eFind out why our valves are different →\u003c\/strong\u003e\u003c\/a\u003e\u003c\/p\u003e","brand":"SYLVANIA","offers":[{"title":"Default Title","offer_id":55365828772188,"sku":"03080","price":89.95,"currency_code":"EUR","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0616\/3775\/5127\/files\/2_aac98ea0-8e4a-4347-8c49-f193b38a36bf.jpg?v=1756653844","url":"https:\/\/vacuumtubestreasures.com\/en-hr\/products\/6sn7gtb-nos-sylvania-chrome-top-green-dot-tested-tube-black-plates-usa-1947","provider":"Vacuum Tubes Treasures","version":"1.0","type":"link"}