{"product_id":"5693-cv3699-rca-nos-special-red-amplitrex-tested-tube-made-in-usa-52","title":"5693 ( CV3699 ) RCA NOS SPECIAL RED AMPLITREX Tested Tube MADE IN USA '52","description":"\u003cp class=\"p1\"\u003e\u003cstrong\u003e5693 ( CV3699 ) RCA NOS SPECIAL RED Tested Tube MADE IN USA '52\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp class=\"p1\"\u003e\u003cb\u003eAMPLITREX Tested – VERY STRONG\u003c\/b\u003e\u003c\/p\u003e\n\u003ch3\u003e\u003cb\u003eGeneral Description\u003c\/b\u003e\u003c\/h3\u003e\n\u003cp class=\"p1\"\u003eThis \u003cspan class=\"s1\"\u003e\u003cb\u003e5693 (CV3699) RCA NOS \"Special Red\"\u003c\/b\u003e\u003c\/span\u003e, manufactured in the United States in \u003cspan class=\"s1\"\u003e\u003cb\u003eMarch 1952 (date code 3-52)\u003c\/b\u003e\u003c\/span\u003e, represents one of the most iconic and sought-after versions of the 6SL7 family.\u003c\/p\u003e\n\u003cp class=\"p1\"\u003eThe \u003cspan class=\"s1\"\u003e\u003cb\u003e5693 Special Red\u003c\/b\u003e\u003c\/span\u003e series is universally recognized for its selected construction and superior quality standards compared to standard versions. The characteristic \u003cspan class=\"s1\"\u003e\u003cb\u003ered coating\u003c\/b\u003e\u003c\/span\u003e is not only a distinctive aesthetic element but identifies a production designed to offer \u003cspan class=\"s1\"\u003e\u003cb\u003estability, reliability, and long operational life\u003c\/b\u003e\u003c\/span\u003e.\u003c\/p\u003e\n\u003cp class=\"p1\"\u003eThis tube is distinguished by:\u003c\/p\u003e\n\u003cul\u003e\n\u003cli class=\"p1\"\u003e\u003cb\u003eRCA USA – 1950s production\u003c\/b\u003e\u003c\/li\u003e\n\u003cli class=\"p1\"\u003e\u003cb\u003e5693 \/ CV3699 – special selected version\u003c\/b\u003e\u003c\/li\u003e\n\u003cli class=\"p1\"\u003e\u003cb\u003e\"Special Red\" body\u003c\/b\u003e\u003c\/li\u003e\n\u003cli class=\"p1\"\u003e\u003cb\u003eDate Code 3-52\u003c\/b\u003e\u003c\/li\u003e\n\u003cli class=\"p1\"\u003e\u003cb\u003eNOS (New Old Stock)\u003c\/b\u003e\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp class=\"p1\"\u003eThis is a \u003cspan class=\"s1\"\u003e\u003cb\u003esingle selected and tested tube\u003c\/b\u003e\u003c\/span\u003e, offered for its overall quality and consistent performance.\u003c\/p\u003e\n\u003cp class=\"p1\"\u003e\u003cspan class=\"s1\"\u003eA top-tier offering, combining \u003c\/span\u003e\u003cb\u003ehistorical prestige, selected construction, and benchmark sound reproduction\u003c\/b\u003e\u003cspan class=\"s1\"\u003e.\u003c\/span\u003e\u003c\/p\u003e\n\u003ch3\u003e\u003cb\u003eSonic Characteristics\u003c\/b\u003e\u003c\/h3\u003e\n\u003cp class=\"p1\"\u003e\u003cb\u003eBass\u003c\/b\u003e\u003c\/p\u003e\n\u003cp class=\"p1\"\u003eDeep and controlled, with a solid and authoritative structure that balances the soundstage.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eMidrange\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp class=\"p1\"\u003eRich, refined, and three-dimensional. Vocals emerge with great naturalness and presence, with an extremely elegant harmonic texture.\u003c\/p\u003e\n\u003cp\u003e\u003cb\u003eTreble\u003c\/b\u003e\u003c\/p\u003e\n\u003cp class=\"p1\"\u003eSweet and silky, with natural extension and a consistently smooth, never fatiguing, reproduction.\u003c\/p\u003e\n\u003cp\u003e\u003cb\u003eDynamics\u003c\/b\u003e\u003c\/p\u003e\n\u003cp class=\"p1\"\u003eLinear and controlled, with extremely stable and consistent response.\u003c\/p\u003e\n\u003cp\u003e\u003cb\u003eSoundstage\u003c\/b\u003e\u003c\/p\u003e\n\u003cp class=\"p1\"\u003eWide, airy, and well-focused, with excellent separation and believable depth.\u003c\/p\u003e\n\u003ch3\u003e\u003cb\u003e🎧 Use in Hi-Fi Amplifiers\u003c\/b\u003e\u003c\/h3\u003e\n\u003cp class=\"p1\"\u003eIdeal for:\u003c\/p\u003e\n\u003cul\u003e\n\u003cli class=\"p1\"\u003ehigh-end preamplifiers\u003c\/li\u003e\n\u003cli class=\"p1\"\u003einput stages\u003c\/li\u003e\n\u003cli class=\"p1\"\u003esystems requiring maximum stability and consistency\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp class=\"p1\"\u003eThanks to the \u003cspan class=\"s2\"\u003e\u003cb\u003eSpecial Red\u003c\/b\u003e\u003c\/span\u003e selection, they offer extremely reliable performance, with refined and controlled sound reproduction.\u003c\/p\u003e\n\u003ch3\u003e\u003cb\u003e🎸 Use in Musical Applications\u003c\/b\u003e\u003c\/h3\u003e\n\u003cp class=\"p1\"\u003ePerfect for:\u003c\/p\u003e\n\u003cul\u003e\n\u003cli class=\"p1\"\u003etube preamplifiers\u003c\/li\u003e\n\u003cli class=\"p1\"\u003equality instrument amplifiers\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp class=\"p1\"\u003eThey offer:\u003c\/p\u003e\n\u003cul\u003e\n\u003cli class=\"p1\"\u003ebalanced dynamic response\u003c\/li\u003e\n\u003cli class=\"p1\"\u003egreat definition\u003c\/li\u003e\n\u003cli class=\"p1\"\u003eelegant and musical sonic character\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch3\u003e\u003cb\u003e🎯 Note for Audiophiles and Technicians\u003c\/b\u003e\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli class=\"p1\"\u003e\u003cb\u003eRCA USA – year 1952 (same date codes 3-52)\u003c\/b\u003e\u003c\/li\u003e\n\u003cli class=\"p1\"\u003e\u003cb\u003e5693 \/ CV3699 – Special Red\u003c\/b\u003e\u003c\/li\u003e\n\u003cli style=\"font-weight: bold;\" class=\"p1\"\u003e\u003cstrong\u003eSelected and tested NOS tube\u003c\/strong\u003e\u003c\/li\u003e\n\u003cli class=\"p1\"\u003e\u003cb\u003eVTT Classification: VERY STRONG\u003c\/b\u003e\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp class=\"p1\"\u003eA tube that represents not only a technical choice but a true \u003cspan class=\"s1\"\u003e\u003cb\u003ecult object for enthusiasts and collectors\u003c\/b\u003e\u003c\/span\u003e, capable of offering a \u003cspan class=\"s1\"\u003e\u003cb\u003erefined sonic experience and unique aesthetic presence\u003c\/b\u003e\u003c\/span\u003e, in the full style of the great American tubes of the 1950s.\u003c\/p\u003e\n\u003chr\u003e\n\u003ch3\u003e\u003cstrong\u003eTest Results:\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cp\u003eTube tested on \u003cstrong\u003eAMPLITREX AT-1000 \u003c\/strong\u003eTube Tester:\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eTest Conditions:\u003c\/strong\u003e\u003cspan\u003e \u003cmeta charset=\"utf-8\"\u003eVa = 250V; Vg2 = 100V; Vg = -3V \u003c\/span\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eAverage 100%:\u003c\/strong\u003e\u003cspan\u003e \u003cmeta charset=\"utf-8\"\u003eGm = 1.6 ; Ia = 3.0 mA\u003c\/span\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eTest Result:\u003c\/strong\u003e VERY STRONG\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp\u003e\u003cmeta charset=\"utf-8\"\u003e\u003cstrong\u003eTube:\u003c\/strong\u003e \u003cmeta charset=\"utf-8\"\u003e\u003cspan\u003eGm = 1.6 ; Ia = 2.8 mA\u003c\/span\u003e\u003c\/p\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\u003eLow. Tested and suitable for hi-fi use, including phono stages 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\u003eConditions:\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli data-start=\"221\" data-end=\"371\"\u003e\n\u003cstrong data-start=\"223\" data-end=\"233\"\u003eCondition:\u003c\/strong\u003e NOS - New Old Stock - Tested and working - Supplied in our custom box for optimal protection. \u003c\/li\u003e\n\u003cli data-start=\"372\" data-end=\"456\"\u003e\n\u003cstrong data-start=\"374\" data-end=\"391\"\u003eFunctionality:\u003c\/strong\u003e Perfectly operational, with excellent test results.\u003c\/li\u003e\n\u003cli data-start=\"457\" data-end=\"672\"\u003e\n\u003cstrong data-start=\"459\" data-end=\"484\"\u003eCosmetic Condition:\u003c\/strong\u003e Excellent – Markings very well preserved, minimal signs of age. See photos for details.\u003c\/li\u003e\n\u003cli data-start=\"673\" data-end=\"797\"\u003e\n\u003cstrong data-start=\"675\" data-end=\"703\"\u003eManufacturing Code:\u003c\/strong\u003e 3-52 → RMA\/EIA Open Date Code → manufactured in the 52nd week of 1953 → Radio Corporation of America, Camden, N. J.\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp\u003e\u003cmeta charset=\"utf-8\"\u003e\u003ca rel=\"noopener\" title=\"Perché le nostre valvole sono diverse – il protocollo VTT che migliora suono, affidabilità e durata\" href=\"https:\/\/vacuumtubestreasures.com\/blogs\/notizie\/perche-le-nostre-valvole-sono-diverse\" target=\"_blank\"\u003e\u003cstrong\u003eDiscover why our tubes are different →\u003c\/strong\u003e\u003c\/a\u003e\u003c\/p\u003e","brand":"RCA","offers":[{"title":"Default Title","offer_id":57347493265756,"sku":"03527L","price":125.0,"currency_code":"AUD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0616\/3775\/5127\/files\/1_2ec85e50-3020-4a71-b224-c2ae999bc75b.jpg?v=1776100476","url":"https:\/\/vacuumtubestreasures.com\/en-au\/products\/5693-cv3699-rca-nos-special-red-amplitrex-tested-tube-made-in-usa-52","provider":"Vacuum Tubes Treasures","version":"1.0","type":"link"}