{"product_id":"jhs-6x4w-ez90-nos-nib-sylvania-matched-pair-black-plates-square-getter-made-in-usa-54-copia","title":"JHS 6X4W EZ90 NOS NIB SYLVANIA Tested Tube Black Plates Square Getter Made in USA '57","description":"\u003cp\u003e\u003cmeta charset=\"utf-8\"\u003e \u003cstrong\u003eJHS 6X4W EZ90 NOS NIB SYLVANIA Tested Tube Black Plates Square Getter Made in USA '57\u003c\/strong\u003e\u003cbr\u003e\u003c\/p\u003e\n\u003ch3\u003e\u003cstrong\u003eDescription:\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cp data-end=\"874\" data-start=\"424\"\u003eThe Sylvania JHS 6X4W (EZ90), manufactured in the USA in 1957 and supplied in \u003cstrong data-end=\"524\" data-start=\"513\"\u003eNOS NIB\u003c\/strong\u003e (New Old Stock – New in Box) condition, represent one of the most prestigious military versions of this double half-wave rectifier.\u003cbr data-end=\"669\" data-start=\"666\"\u003eThe acronym \u003cstrong data-end=\"716\" data-start=\"678\"\u003eJHS (Joint Army-Navy\/Signal Corps)\u003c\/strong\u003e identifies American military production, selected to withstand critical applications where maximum reliability and long life were required.\u003c\/p\u003e\n\u003cp data-end=\"1316\" data-start=\"876\"\u003eUnlike the common 6X4, the \u003cstrong data-end=\"923\" data-start=\"916\"\u003e“W”\u003c\/strong\u003e acronym indicates the \u003cstrong data-end=\"957\" data-start=\"943\"\u003eruggedized\u003c\/strong\u003e version, that is, reinforced to resist shocks, vibrations and severe operating conditions. \u003cbr data-end=\"1043\" data-start=\"1040\"\u003eAs reported in the datasheet, the 6X4W was designed to operate in half-wave or full-wave rectification, even in combination with vibratory inverters, and was specifically tested for industrial and military applications subjected to intense mechanical shock and vibration.\u003c\/p\u003e\n\u003cp data-end=\"1570\" data-start=\"1318\"\u003eThis valve, equipped with \u003cstrong data-end=\"1383\" data-start=\"1351\"\u003eblack plates and square getter\u003c\/strong\u003e , combines construction robustness, operational silence and a unique historical charm, making it ideal for high-quality hi-fi and philological restorations of vintage military or civilian equipment.\u003c\/p\u003e\n\u003ch3 data-end=\"1626\" data-start=\"1572\"\u003eTimbral characteristics and sound behavior\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli data-end=\"1728\" data-start=\"1629\"\u003e\u003cstrong data-end=\"1638\" data-start=\"1629\"\u003eBass\u003c\/strong\u003e : Compact and tight, with firm control that adds precision to the low register.\u003c\/li\u003e\n\u003cli data-end=\"1881\" data-start=\"1731\"\u003e\u003cstrong data-end=\"1739\" data-start=\"1731\"\u003eMids\u003c\/strong\u003e : Clear and linear, with a natural sound free of artificial coloration. Voices and acoustic instruments emerge with great realism.\u003c\/li\u003e\n\u003cli data-end=\"1991\" data-start=\"1884\"\u003e\u003cstrong data-end=\"1892\" data-start=\"1884\"\u003eHighs\u003c\/strong\u003e : defined and fluid, never harsh, with an elegant detail that gives brilliance without tiring.\u003c\/li\u003e\n\u003cli data-end=\"2102\" data-start=\"1994\"\u003e\u003cstrong data-end=\"2006\" data-start=\"1994\"\u003eDynamics\u003c\/strong\u003e : prompt and consistent, capable of ensuring stable power even in complex passages.\u003c\/li\u003e\n\u003cli data-end=\"2220\" data-start=\"2105\"\u003e\u003cstrong data-end=\"2119\" data-start=\"2105\"\u003eSoundstage\u003c\/strong\u003e : Stable and well-focused soundstage, with noise reduction and deeper black background.\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp data-end=\"2438\" data-start=\"2222\"\u003e🎧 \u003cstrong data-end=\"2255\" data-start=\"2225\"\u003eUse in Hi-Fi amplifiers\u003c\/strong\u003e\u003cbr data-end=\"2258\" data-start=\"2255\"\u003ePerfect for hi-fi equipment and tube tuners using EZ90\/6X4 rectifiers, these Sylvania JHS ensure clean power, reliability and long operating life.\u003c\/p\u003e\n\u003cp data-end=\"2647\" data-start=\"2440\"\u003e🎸 \u003cstrong data-end=\"2490\" data-start=\"2443\"\u003eUse in musical instrument amplifiers\u003c\/strong\u003e\u003cbr data-end=\"2493\" data-start=\"2490\"\u003eIn vintage musical instrument amplifiers, they guarantee a warm and quiet sound, with stable harmonic response and free from unwanted noise.\u003c\/p\u003e\n\u003cp data-end=\"3269\" data-start=\"2649\"\u003e🎯 \u003cstrong data-end=\"2684\" data-start=\"2652\"\u003eNote for audiophiles and technicians\u003c\/strong\u003e\u003cbr data-end=\"2687\" data-start=\"2684\"\u003eThe \u003cstrong data-end=\"2784\" data-start=\"2697\"\u003eJHS 6X4W (EZ90) Sylvania – Black Plates – Square Getter – NOS NIB – Made in USA '57\u003c\/strong\u003e\u0026nbsp;represents one of the rarest and most prestigious versions of this rectifier.\u003cbr data-end=\"2867\" data-start=\"2864\"\u003eThanks to the reinforced “W” construction, it is particularly suitable not only for philological restorations, but also for those seeking maximum operational reliability in hi-fi systems and musical instruments.\u003cbr data-end=\"3062\" data-start=\"3059\"\u003eAn ideal choice for collectors, restorers and enthusiasts who wish to combine impeccable functionality, historical value and construction authenticity typical of 1950s American military production.\u003c\/p\u003e\n\u003chr\u003e\n\u003ch3\u003e\u003cstrong\u003eTest Results:\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cp\u003e\u003cspan\u003eTubes tested on \u003cstrong\u003eFunke W19\u003c\/strong\u003e Tube tester:\u003c\/span\u003e\u003cbr\u003e\u003cspan\u003e\u003cstrong\u003eVoltage Test:\u003c\/strong\u003e\u003cmeta charset=\"utf-8\"\u003e Va = 60V, Vf = 6.3V\u003c\/span\u003e\u003cbr\u003e\u003cspan\u003eAverage 100% Ia = 42 mA\u003c\/span\u003e\u003cbr\u003e\u003cstrong\u003eTest Result: VERY STRONG\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cspan\u003ePlate current\u003c\/span\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eValve:\u003c\/strong\u003e\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003e\u003cspan\u003e\u003cstrong\u003eSection 1:\u003c\/strong\u003e Ia = 48 mA\u003c\/span\u003e\u003c\/li\u003e\n\u003cli\u003e\u003cspan\u003e\u003cstrong\u003eSection 2:\u003c\/strong\u003e Ia = 47 mA\u003c\/span\u003e\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp\u003e\u003cspan\u003ePlate current:\u003c\/span\u003e\u003cstrong\u003e\u003c\/strong\u003e\u003c\/p\u003e\n\u003ch3\u003e\u003cstrong\u003eAdditional Tests\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003e\u003cstrong\u003eMicrophonics:\u003c\/strong\u003e Standard. Tested and approved for use in hi-fi and guitar amplifiers.\u003c\/li\u003e\n\u003cli\u003e\u003cstrong\u003eOutput Quality:\u003c\/strong\u003e\u003cmeta charset=\"utf-8\"\u003e \u003cspan\u003eExcellent – Very strong and stable output, no fluctuations.\u003c\/span\u003e\u003c\/li\u003e\n\u003cli\u003e\u003cstrong\u003eShort circuits and GAS:\u003c\/strong\u003e Absent.\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\u003eConditions:\u003cspan\u003e \u003c\/span\u003e\u003c\/strong\u003eNOS - NIB - New Old Stock, New In Box - Tested and working - Supplied in original box.\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\u003eGood – Lettering partially eroded, but still legible. Valve body in good condition. See photos for details.\u003c\/span\u003e\u003cstrong\u003e\u003cbr\u003e\u003c\/strong\u003e\u003c\/li\u003e\n\u003cli\u003e\u003cstrong\u003eManufacturing Code:\u003cspan\u003e \u003c\/span\u003e\u003c\/strong\u003e702 - Manufactured in the 2nd week of 1957\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp\u003e\u003cmeta charset=\"utf-8\"\u003e\u003ca 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":55482965262684,"sku":"03111","price":29.0,"currency_code":"GBP","in_stock":false}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0616\/3775\/5127\/files\/2_a8e694e1-3944-42fe-bd05-2a2d92397ac1.jpg?v=1757947935","url":"https:\/\/vacuumtubestreasures.com\/en-gb\/products\/jhs-6x4w-ez90-nos-nib-sylvania-matched-pair-black-plates-square-getter-made-in-usa-54-copia","provider":"Vacuum Tubes Treasures","version":"1.0","type":"link"}