{"product_id":"6sn7gtb-nos-nib-sylvania-chrome-top-export-quality-amplitrex-tested-tube-black-plates-usa-50s","title":"6SN7GTB NOS NIB SYLVANIA CHROME TOP Export Quality AMPLITREX Tested Tube Black Plates USA '50s","description":"\u003cp\u003e\u003cstrong\u003e6SN7GTB NOS NIB SYLVANIA CHROME TOP Export Quality AMPLITREX Tested Tube Black Plates USA '50s\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp data-start=\"245\" data-end=\"817\"\u003e\u003cspan data-start=\"248\" data-end=\"290\"\u003eThe\u003c\/span\u003e\u003cstrong data-start=\"248\" data-end=\"290\"\u003e 6SN7 GTB Sylvania \u003c\/strong\u003e\u003cstrong\u003eExport Quality\u003c\/strong\u003e, with \u003cstrong data-start=\"309\" data-end=\"325\"\u003eblack plates\u003c\/strong\u003e and a \u003cstrong data-start=\"327\" data-end=\"342\"\u003echrome top\u003c\/strong\u003e, represents one of the most refined and consistent NOS configurations of post-war American production. The green dot was a factory marking applied by Sylvania to identify tubes selected for low noise and microphonics, intended for critical applications in military, professional, and high-end audio fields. The construction quality of this generation makes it an excellent choice where \u003cstrong data-start=\"726\" data-end=\"785\"\u003etonal uniformity, quietness, and natural musicality\u003c\/strong\u003e are essential requirements.\u003c\/p\u003e\n\u003cp data-start=\"819\" data-end=\"1000\"\u003eThese tubes are distinguished by a \u003cstrong data-start=\"857\" data-end=\"895\"\u003etransparent and three-dimensional sound\u003c\/strong\u003e, with a \u003cstrong data-start=\"914\" data-end=\"936\"\u003eneutral yet musical\u003c\/strong\u003e character, capable of enhancing microdynamics without forced coloration.\u003c\/p\u003e\n\u003cp data-start=\"1007\" data-end=\"1270\"\u003e\u003cstrong data-start=\"1007\" data-end=\"1016\"\u003eBass\u003c\/strong\u003e: tight and well-defined. The low end is \u003cstrong data-start=\"1056\" data-end=\"1100\"\u003earticulate, dry, and free from bloat\u003c\/strong\u003e, offering a \u003cstrong data-start=\"1129\" data-end=\"1154\"\u003econtrolled and stable\u003c\/strong\u003e harmonic foundation. Perfect for maintaining \u003cstrong data-start=\"1179\" data-end=\"1205\"\u003eclarity and precision\u003c\/strong\u003e in the lower registers, even with complex passages.\u003c\/p\u003e\n\u003cp data-start=\"1272\" data-end=\"1546\"\u003e\u003cstrong data-start=\"1272\" data-end=\"1280\"\u003eMids\u003c\/strong\u003e: clear and natural. The mid-range is \u003cstrong data-start=\"1321\" data-end=\"1357\"\u003ebalanced and free from artifacts\u003c\/strong\u003e, with \u003cstrong data-start=\"1363\" data-end=\"1384\"\u003ewell-centered vocals\u003c\/strong\u003e and a \u003cstrong data-start=\"1396\" data-end=\"1435\"\u003erealistic reproduction of acoustic instruments\u003c\/strong\u003e. There is no artificial emphasis, but a \u003cstrong data-start=\"1473\" data-end=\"1497\"\u003econsistent transparency\u003c\/strong\u003e that facilitates deep and engaging listening.\u003c\/p\u003e\n\u003cp data-start=\"1548\" data-end=\"1768\"\u003e\u003cstrong data-start=\"1548\" data-end=\"1556\"\u003eHighs\u003c\/strong\u003e: fine and non-fatiguing. The high range is \u003cstrong data-start=\"1598\" data-end=\"1627\"\u003edelicate, extended, and airy\u003c\/strong\u003e, with a \u003cstrong data-start=\"1637\" data-end=\"1662\"\u003ediscreet brilliance\u003c\/strong\u003e and \u003cstrong data-start=\"1668\" data-end=\"1716\"\u003edetail well integrated into the musical fabric\u003c\/strong\u003e. Excellent for long, fatigue-free listening sessions.\u003c\/p\u003e\n\u003cp data-start=\"1770\" data-end=\"2053\"\u003e\u003cstrong data-start=\"1770\" data-end=\"1782\"\u003eDynamics\u003c\/strong\u003e: fluid and modulated. The dynamic response is \u003cstrong data-start=\"1826\" data-end=\"1841\"\u003eprogressive\u003c\/strong\u003e, capable of reproducing \u003cstrong data-start=\"1864\" data-end=\"1900\"\u003eminimal nuances with naturalness\u003c\/strong\u003e, while also sustaining \u003cstrong data-start=\"1924\" data-end=\"1945\"\u003eenergetic passages\u003c\/strong\u003e without stiffening. The tubes react \u003cstrong data-start=\"1995\" data-end=\"2020\"\u003equickly but controllably\u003c\/strong\u003e, ensuring constant musicality.\u003c\/p\u003e\n\u003cp data-start=\"2055\" data-end=\"2341\"\u003e\u003cstrong data-start=\"2055\" data-end=\"2069\"\u003eSoundstage\u003c\/strong\u003e: wide and stable. The soundstage is \u003cstrong data-start=\"2106\" data-end=\"2126\"\u003ewide and deep\u003c\/strong\u003e, with \u003cstrong data-start=\"2132\" data-end=\"2173\"\u003eexcellent instrument placement\u003c\/strong\u003e and \u003cstrong data-start=\"2180\" data-end=\"2208\"\u003econsistent layering\u003c\/strong\u003e. The \u003cstrong\u003eprecision of the stereo image\u003c\/strong\u003e benefits from the electrical stability and constructive consistency typical of this Sylvania production.\u003c\/p\u003e\n\u003cp data-start=\"2348\" data-end=\"2713\"\u003e🎧 \u003cstrong data-start=\"2351\" data-end=\"2398\"\u003eUse in Stereo Hi-Fi Amplifiers\u003c\/strong\u003e\u003cbr data-start=\"2398\" data-end=\"2401\"\u003e\u003cmeta charset=\"utf-8\"\u003eAn ideal choice for high-level preamplifiers and driver stages. The \u003cstrong data-end=\"1796\" data-start=\"1768\"\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, with extended listening sessions always enjoyable.\u003cbr\u003e\u003c\/p\u003e\n\u003cp data-start=\"2715\" data-end=\"3044\"\u003e🎸 \u003cstrong data-start=\"2718\" data-end=\"2756\"\u003eUse in Instrument Amplifiers\u003c\/strong\u003e\u003cbr data-start=\"2756\" data-end=\"2759\"\u003e\u003cmeta charset=\"utf-8\"\u003eAlso highly appreciated in boutique and vintage guitar amplifiers, where it delivers a round, harmonic, and natural sound. Its soft yet detailed reproduction makes it ideal for blues, jazz, and classic rock.\u003cbr\u003e\u003c\/p\u003e\n\u003cp data-start=\"3046\" data-end=\"3436\"\u003e🎯 \u003cstrong data-start=\"3049\" data-end=\"3081\"\u003eNote for audiophiles and technicians\u003c\/strong\u003e\u003cbr data-start=\"3081\" data-end=\"3084\"\u003e\u003cmeta charset=\"utf-8\"\u003eThe \u003cstrong data-end=\"2321\" data-start=\"2266\"\u003e6SN7 GTB Sylvania Chrome Top Green Dot Black Plates\u003c\/strong\u003e is one of the most sought-after variants of this iconic tube.\u003cbr data-end=\"2395\" data-start=\"2392\"\u003eIt combines the military\/industrial construction solidity of the era with the tonal refinement that made Sylvania a legendary name among audiophiles and collectors.\u003cbr data-end=\"2559\" data-start=\"2556\"\u003eA rare opportunity to own not just a tested NOS tube, but a true fragment of \u003cstrong data-end=\"2681\" data-start=\"2653\"\u003eauthentic American sound\u003c\/strong\u003e.\u003c\/p\u003e\n\u003chr\u003e\n\u003cp data-start=\"3046\" data-end=\"3436\"\u003e\u003cstrong\u003eTest Results:\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eTubes tested on \u003cstrong\u003eAmplitrex AT-1000\u003c\/strong\u003e Tube tester:\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eTest Conditions:\u003c\/strong\u003e Va = 250V, Vg = -8V\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eAverage 100%\u003c\/strong\u003e \u003cstrong\u003eGm = 2600 ; Ia = 9.0 mA\u003c\/strong\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp\u003e\u003cstrong\u003eTube :\u003c\/strong\u003e\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003eSection 1: Gm = 2900 ; Ia = 9.2 mA\u003c\/li\u003e\n\u003cli\u003eSection 2: Gm = 2700 ; Ia = 8.0 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\u003eEmission Quality:\u003c\/strong\u003e Excellent – Very strong and stable emission, without fluctuations.\u003c\/span\u003e\u003c\/li\u003e\n\u003cli\u003e\u003cspan\u003e\u003cstrong\u003eShorts and GAS:\u003c\/strong\u003e Absent.\u003c\/span\u003e\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003chr\u003e\n\u003ch3\u003e\u003cstrong\u003eCondition:\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eCondition:\u003c\/strong\u003e NOS - NIB - New Old Stock, New In Box - Tested and working - Supplied in Original box.\u003cstrong\u003e\u003cbr\u003e\u003c\/strong\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eFunctionality: \u003c\/strong\u003ePerfectly operational.\u003cstrong\u003e\u003cbr\u003e\u003c\/strong\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eCosmetic Condition:\u003c\/strong\u003e\u003cspan\u003e Excellent – Markings excellently preserved, minimal signs of age. See photos for details.\u003c\/span\u003e\u003cstrong\u003e\u003cbr\u003e\u003c\/strong\u003e\u003cstrong\u003eManufacturing Code:\u003cspan\u003e \u003c\/span\u003e\u003c\/strong\u003eundecipherable, identifiable by construction characteristics. 1950s\u003cmeta charset=\"utf-8\"\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp\u003e\u003cmeta charset=\"utf-8\"\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":"SYLVANIA","offers":[{"title":"Default Title","offer_id":57347680207196,"sku":"03528","price":107.0,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0616\/3775\/5127\/files\/1_311f63ba-7e96-4750-9741-5e69ce080de8.jpg?v=1776101704","url":"https:\/\/vacuumtubestreasures.com\/en-us\/products\/6sn7gtb-nos-nib-sylvania-chrome-top-export-quality-amplitrex-tested-tube-black-plates-usa-50s","provider":"Vacuum Tubes Treasures","version":"1.0","type":"link"}