{"product_id":"12ax7-ecc83-rca-matched-pair-long-black-plates-square-tilt-getter-made-in-usa-58","title":"12AX7 \/ ECC83 RCA Matched Pair Long Black Plates Square Tilt getter Made in USA '58","description":"\u003cp\u003e\u003cspan class=\"s1\"\u003e\u003cb\u003e12AX7 \/ ECC83 RCA Matched Pair Long Black Plates Square Tilt Getter Made in USA 1958\u003c\/b\u003e\u003c\/span\u003e\u003c\/p\u003e\n\u003cp class=\"p2\"\u003e\u003cb\u003eAMPLITREX Tested – Low Noise \u0026amp; Microphonics – Vintage American Black Plates\u003c\/b\u003e\u003c\/p\u003e\n\u003ch3\u003e\u003cstrong\u003eDescription:\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cp class=\"p1\"\u003eThis matched pair of \u003cspan class=\"s1\"\u003e\u003cb\u003e12AX7 \/ ECC83 RCA\u003c\/b\u003e\u003c\/span\u003e, \u003cspan class=\"s1\"\u003e\u003cb\u003eMade in USA 1958\u003c\/b\u003e\u003c\/span\u003e production, represents one of the most fascinating and sought-after configurations from the golden age of American small signal tubes.\u003c\/p\u003e\n\u003cp class=\"p1\"\u003eThe construction with \u003cspan class=\"s1\"\u003e\u003cb\u003eLong Black Plates\u003c\/b\u003e\u003c\/span\u003e and rare \u003cspan class=\"s1\"\u003e\u003cb\u003eSquare Tilt Getter\u003c\/b\u003e\u003c\/span\u003e identifies RCA production from the late 1950s, particularly appreciated for its musicality, harmonic richness, and strong sonic personality. This type is historically much loved by both audiophiles and enthusiasts of vintage musical instrument amplifiers.\u003c\/p\u003e\n\u003cp class=\"p1\"\u003eThe tubes are used, carefully tested and selected in our laboratory using the \u003cspan class=\"s1\"\u003e\u003cb\u003eAMPLITREX AT-1000 Tube Tester\u003c\/b\u003e\u003c\/span\u003e, with particular attention to low noise, controlled microphonics, and operational consistency of the pair.\u003c\/p\u003e\n\u003cp class=\"p1\"\u003eThis pair is offered as a \u003cspan class=\"s1\"\u003e\u003cb\u003eselected Matched Pair\u003c\/b\u003e\u003c\/span\u003e, with overall consistent electrical behavior, good operational uniformity, and very interesting sonic characteristics in hi-fi and musical applications.\u003c\/p\u003e\n\u003cp class=\"p1\"\u003eFrom an aesthetic point of view, the pair is in particularly beautiful and very clean condition for its age: the RCA silkscreen printing is still well preserved, the internal structures are visually very appealing, and the overall appearance retains the typical aesthetic impact of authentic 1950s American black plates.\u003c\/p\u003e\n\u003cp class=\"p2\"\u003eThe value of this pair is strongly linked to the combination of:\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003eoriginal USA RCA brand;\u003c\/li\u003e\n\u003cli\u003evintage 1958 production;\u003c\/li\u003e\n\u003cli\u003eLong Black Plates structure;\u003c\/li\u003e\n\u003cli\u003eSquare Tilt Getter;\u003c\/li\u003e\n\u003cli\u003ematched pair;\u003c\/li\u003e\n\u003cli\u003elow noise;\u003c\/li\u003e\n\u003cli\u003elow microphonics;\u003c\/li\u003e\n\u003cli\u003eexcellent aesthetic presence.\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003chr\u003e\n\u003ch3\u003e\u003cspan class=\"s1\"\u003e\u003cb\u003eSonic Characteristics\u003c\/b\u003e\u003c\/span\u003e\u003c\/h3\u003e\n\u003cp class=\"p1\"\u003eRCA long black plates from the 1950s are famous for a broad, musical, and harmonically rich sound presentation, with a deeply American character: full-bodied, natural, and engaging.\u003c\/p\u003e\n\u003cp class=\"p1\"\u003eThis pair clearly retains that typical vintage RCA sonic signature, capable of combining musicality, fluidity, and an extremely pleasant harmonic texture.\u003c\/p\u003e\n\u003cp\u003e\u003cspan class=\"s1\"\u003e\u003cb\u003eBass\u003c\/b\u003e\u003c\/span\u003e\u003c\/p\u003e\n\u003cp class=\"p1\"\u003eThe bass range is full, round, and natural, with a good sense of body and presence. The bass maintains musicality and control without being artificially emphasized.\u003c\/p\u003e\n\u003cp\u003e\u003cspan class=\"s1\"\u003e\u003cb\u003eMids\u003c\/b\u003e\u003c\/span\u003e\u003c\/p\u003e\n\u003cp class=\"p1\"\u003eThe mids are probably the most alluring aspect of this RCA production. Vocals are material, dense, and believable, while acoustic instruments and harmonics retain a rich and very musical texture.\u003c\/p\u003e\n\u003cp class=\"p1\"\u003eThat typical vintage American softness is present, making these RCAs particularly satisfying for long listening sessions.\u003c\/p\u003e\n\u003cp\u003e\u003cspan class=\"s1\"\u003e\u003cb\u003eHighs\u003c\/b\u003e\u003c\/span\u003e\u003c\/p\u003e\n\u003cp class=\"p1\"\u003eThe high range is fluid, refined, and never aggressive. Detail remains present but naturally integrated, contributing to a relaxed and elegant listening experience.\u003c\/p\u003e\n\u003cp\u003e\u003cspan class=\"s1\"\u003e\u003cb\u003eDynamics\u003c\/b\u003e\u003c\/span\u003e\u003c\/p\u003e\n\u003cp class=\"p1\"\u003eThe dynamic response appears musical and progressive, with good ability to follow harmonic and dynamic variations without stiffness or harshness.\u003c\/p\u003e\n\u003cp class=\"p4\"\u003eThe soundstage is stable, airy, and well-organized. The image maintains good depth and correct instrument separation, with a very credible and engaging presentation.\u003c\/p\u003e\n\u003chr\u003e\n\u003ch3\u003e\u003cspan class=\"s1\"\u003e\u003cb\u003e🎧 Use in Hi-Fi Amplifiers\u003c\/b\u003e\u003c\/span\u003e\u003c\/h3\u003e\n\u003cp class=\"p2\"\u003eThese RCA ECC83 \/ 12AX7 are particularly suitable for:\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003ehi-fi preamplifiers;\u003c\/li\u003e\n\u003cli\u003eline stages;\u003c\/li\u003e\n\u003cli\u003ephono stages;\u003c\/li\u003e\n\u003cli\u003evintage and modern integrated amplifiers;\u003c\/li\u003e\n\u003cli\u003ecompatible driver stages.\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp class=\"p4\"\u003eThe \u003cspan class=\"s1\"\u003e\u003cb\u003eLow Noise \u0026amp; Microphonics\u003c\/b\u003e\u003c\/span\u003e selection also makes them very interesting for sensitive applications and systems focused on musicality and tonal naturalness.\u003c\/p\u003e\n\u003chr\u003e\n\u003ch3\u003e\u003cspan class=\"s1\"\u003e\u003cb\u003e🎸 Use in Musical Applications\u003c\/b\u003e\u003c\/span\u003e\u003c\/h3\u003e\n\u003cp class=\"p1\"\u003eIn the world of guitar amplifiers, RCA long black plates from the 1950s are considered by many enthusiasts to be among the most musical and fascinating American ECC83s ever produced.\u003c\/p\u003e\n\u003cp class=\"p2\"\u003eThis pair offers:\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003eexcellent harmonic response;\u003c\/li\u003e\n\u003cli\u003erich and three-dimensional mids;\u003c\/li\u003e\n\u003cli\u003egreat musicality;\u003c\/li\u003e\n\u003cli\u003enatural dynamic behavior;\u003c\/li\u003e\n\u003cli\u003econtrolled noise and low microphonics.\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp class=\"p4\"\u003eCharacteristics that make it very interesting for use in vintage, boutique amplifiers, and studio applications.\u003c\/p\u003e\n\u003chr\u003e\n\u003ch3\u003e\u003cspan class=\"s1\"\u003e\u003cb\u003e🎯 Note for Audiophiles and Technicians\u003c\/b\u003e\u003c\/span\u003e\u003c\/h3\u003e\n\u003cp class=\"p2\"\u003eThis pair represents a vintage American selection of strong historical and aesthetic appeal, designed for those who desire authentic \u003cspan class=\"s1\"\u003e\u003cb\u003e1950s USA RCA black plates\u003c\/b\u003e\u003c\/span\u003e with:\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003eLong Black Plates construction;\u003c\/li\u003e\n\u003cli\u003eSquare Tilt Getter;\u003c\/li\u003e\n\u003cli\u003ematched pair;\u003c\/li\u003e\n\u003cli\u003ehigh quietness;\u003c\/li\u003e\n\u003cli\u003elow microphonics;\u003c\/li\u003e\n\u003cli\u003etypical vintage RCA musicality.\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp class=\"p1\"\u003eAlthough these are used vintage tubes, their overall value remains very high due to their build quality, the rarity of their internal configuration, their aesthetic beauty, and the sonic character typical of the best American productions of the era.\u003c\/p\u003e\n\u003cp class=\"p1\"\u003eA 1958 RCA black plates pair with strong vintage American charm, selected for musicality, quietness, and sonic authenticity, in line with the Vacuum Tubes Treasures philosophy.\u003c\/p\u003e\n\u003chr\u003e\n\u003ch3\u003e\u003cstrong\u003eTest Results\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cp\u003e\u003cstrong\u003eTested on AMPLITREX AT-1000 Tube Tester\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eVoltage Test:\u003cspan\u003e\u0026nbsp;\u003c\/span\u003e\u003c\/strong\u003eVa = 250V, Vg = -2V\u003cstrong\u003e\u003cbr\u003eAverage 100%:\u003cspan\u003e\u0026nbsp;\u003c\/span\u003e\u003c\/strong\u003eGm = 1600 ; Ia = 1.2 mA\u003cstrong\u003e\u003cbr\u003eTEST RESULT: \u003c\/strong\u003eGOOD\u003cstrong\u003e\u003cbr\u003e\u003c\/strong\u003e\u003cstrong\u003e\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eTube #11\u003c\/strong\u003e:\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003e\u003cstrong\u003eSection 1\u003c\/strong\u003e: Gm = 1100 ; Ia = 0.8 mA\u003c\/li\u003e\n\u003cli\u003e\u003cstrong\u003eSection 2\u003c\/strong\u003e: Gm = 1200 ; Ia = 0.8 mA\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp\u003e\u003cstrong\u003eTube #2\u003c\/strong\u003e:\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003e\u003cstrong\u003eSection 1\u003c\/strong\u003e: Gm = 1200 ; Ia = 0.7 mA\u003c\/li\u003e\n\u003cli\u003e\u003cstrong\u003eSection 2\u003c\/strong\u003e: Gm = 1200 ; Ia = 0.9 mA\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cdiv\u003e\u003cstrong\u003e\u003c\/strong\u003e\u003cbr\u003e\u003c\/div\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 suitable for use in hi-fi systems and guitar amplifiers.\u003c\/span\u003e\u003c\/li\u003e\n\u003cli\u003e\u003cstrong\u003eNoise:\u003c\/strong\u003e Low and well controlled. Quiet operation in hi-fi and musical amplifiers in designated positions.\u003c\/li\u003e\n\u003cli\u003e\u003cspan\u003e\u003cstrong\u003eEmission Quality:\u003c\/strong\u003e\u0026nbsp;Good and regular emission, suitable for any application.\u003c\/span\u003e\u003c\/li\u003e\n\u003cli\u003e\u003cspan\u003e\u003cstrong\u003eShorts and GAS:\u003c\/strong\u003e\u0026nbsp;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\u003eConditions:\u003c\/strong\u003e Vintage Tubes - Tested and fully functional. Supplied in our custom box for optimal protection.\u0026nbsp;\u003cstrong\u003e\u003cbr\u003e\u003c\/strong\u003e\u003c\/li\u003e\n\u003cli\u003e\u003cstrong\u003eFunctionality:\u0026nbsp;\u003c\/strong\u003ePerfectly operational.\u003cstrong\u003e\u003cbr\u003e\u003c\/strong\u003e\u003c\/li\u003e\n\u003cli\u003e\u003cstrong\u003eAesthetic conditions:\u003c\/strong\u003e\u003cspan\u003e Excellent – Labels excellently preserved, minimal signs of time. See photos for details.\u003c\/span\u003e\u003cstrong\u003e\u003cbr\u003e\u003c\/strong\u003e\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp\u003e\u003cstrong\u003eManufacturing Code:\u003c\/strong\u003e\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003e58-13 → RMA\/EIA Open Date Code → manufactured 13th week of 1958 → Radio Corporation of America, Camden, N. J.\u003c\/li\u003e\n\u003cli\u003e58-09 → RMA\/EIA Open Date Code → manufactured 9th week of 1958 → Radio Corporation of America, Camden, N. J.\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\u003eDiscover why our tubes are different →\u003c\/strong\u003e\u003c\/a\u003e\u003c\/p\u003e","brand":"RCA","offers":[{"title":"Default Title","offer_id":57643431166300,"sku":"03598","price":168.0,"currency_code":"GBP","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0616\/3775\/5127\/files\/1_9bad0dbc-dc54-48e3-95f2-27456c87dc18.jpg?v=1778776431","url":"https:\/\/vacuumtubestreasures.com\/en-gb\/products\/12ax7-ecc83-rca-matched-pair-long-black-plates-square-tilt-getter-made-in-usa-58","provider":"Vacuum Tubes Treasures","version":"1.0","type":"link"}