{"product_id":"12bh7a-rca-nos-nib-black-plates-foil-dimpled-getter-usa-1950s-amplitrex-tested","title":"12BH7A RCA NOS NIB Black Plates Dimpled D-Foil Getter USA 1950s AMPLITREX Tested","description":"\u003ch3\u003e\u003cspan class=\"s1\"\u003e\u003cb\u003e12BH7A RCA NOS NIB Black Plates Dimpled D-Foil Getter – Made in USA – 1950s\u003c\/b\u003e\u003c\/span\u003e\u003c\/h3\u003e\n\u003cp class=\"p2\"\u003e\u003cb\u003eAMPLITREX Tested – VERY STRONG – Low Noise \u0026amp; Microphonics – Vintage American RCA Production\u003c\/b\u003e\u003c\/p\u003e\n\u003ch3\u003e\u003cspan class=\"s1\"\u003e\u003cb\u003eTest Results\u003c\/b\u003e\u003c\/span\u003e\u003c\/h3\u003e\n\u003cp class=\"p2\"\u003eTubes tested on\u003cspan\u003e \u003c\/span\u003e\u003cspan class=\"s1\"\u003e\u003cb\u003eAMPLITREX AT-1000 Tube Tester\u003c\/b\u003e\u003c\/span\u003e\u003c\/p\u003e\n\u003cp class=\"p3\"\u003e\u003cb\u003eTest Conditions:\u003c\/b\u003e\u003cspan\u003e \u003c\/span\u003eVa = 250V, Vg = -10.5V\u003cbr\u003e\u003cspan class=\"s1\"\u003e\u003cb\u003eAverage 100%:\u003c\/b\u003e\u003c\/span\u003e\u003cspan\u003e \u003c\/span\u003eGm = 3.10 ; Ia = 11.5 mA\u003cbr\u003e\u003cspan class=\"s1\"\u003e\u003cb\u003eTest Result:\u003c\/b\u003e\u003c\/span\u003e VERY STRONG\u003c\/p\u003e\n\u003cdiv\u003e\u003cstrong\u003eTube:\u003c\/strong\u003e\u003c\/div\u003e\n\u003cul\u003e\n\n\u003cli\u003e\u003cspan\u003e\u003cstrong\u003e Section 1:\u003c\/strong\u003e Gm = 3.70 ; Ia = 15.6 mA\u003c\/span\u003e\u003c\/li\u003e\n\n\u003cli\u003e\u003cspan\u003e\u003cstrong\u003e Section 2:\u003c\/strong\u003e Gm = 3.30 ; Ia = \u003cmeta charset=\"utf-8\"\u003e11.8 mA\u003c\/span\u003e\u003c\/li\u003e\n\n\n\u003c\/ul\u003e\n\u003ch3\u003e\u003cspan class=\"s1\"\u003e\u003cb\u003eAdditional Tests Performed\u003c\/b\u003e\u003c\/span\u003e\u003c\/h3\u003e\n\u003cul\u003e\n\n\u003cli class=\"p2\"\u003e\n\n\u003cmeta charset=\"utf-8\"\u003e \u003cstrong\u003eBurn-in \/ Stability Test:\u003c\/strong\u003e 48h – OK\u003c\/li\u003e\n\n\u003cli class=\"p3\"\u003e\n\n\u003cb\u003eMicrophonics:\u003c\/b\u003e Low. Tested and suitable for use in hi-fi equipment and guitar amplifiers, even in the most sensitive audio stages.\u003c\/li\u003e\n\n\u003cli class=\"p3\"\u003e\n\n\u003cb\u003eBalance:\u003c\/b\u003e The sections are not perfectly aligned. The tube is suitable for use in hi-fi systems in non-critical stages (input or driver) and in guitar amplifiers. Not recommended as a phase inverter or in applications requiring strict balance between sections.\u003c\/li\u003e\n\n\u003cli class=\"p3\"\u003e\n\n\u003cb\u003eEmission Quality:\u003c\/b\u003e Excellent – Very strong and stable emission, without fluctuations.\u003c\/li\u003e\n\n\u003cli class=\"p2\"\u003e\n\n\u003cb\u003eShorts and GAS:\u003c\/b\u003e\u003cspan class=\"s2\"\u003e Absent.\u003c\/span\u003e\n\n\u003c\/li\u003e\n\n\n\u003c\/ul\u003e\n\u003ch3 class=\"p2\"\u003e\u003cb\u003eDescription:\u003c\/b\u003e\u003c\/h3\u003e\n\u003cp\u003e\u003cspan\u003ePrecious \u003c\/span\u003e\u003cstrong\u003e\u003cspan\u003e12BH7A RCA NOS NIB\u003c\/span\u003e\u003c\/strong\u003e\u003cspan\u003e, vintage American production attributable to the \u003c\/span\u003e\u003cstrong\u003e\u003cspan\u003e1950s\u003c\/span\u003e\u003c\/strong\u003e\u003cspan\u003e, featuring the sought-after \u003c\/span\u003e\u003cstrong\u003e\u003cspan\u003eBlack Plates with Dimpled D-Foil Getter\u003c\/span\u003e\u003c\/strong\u003e\u003cspan\u003e construction, a particularly interesting configuration of the first RCA productions of the 12BH7 family.\u003c\/span\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cspan\u003eThe combination of the classic \u003c\/span\u003e\u003cstrong\u003e\u003cspan\u003eRCA Black Plates\u003c\/span\u003e\u003c\/strong\u003e\u003cspan\u003e with the distinctive \u003c\/span\u003e\u003cstrong\u003e\u003cspan\u003edimpled D-Foil Getter\u003c\/span\u003e\u003c\/strong\u003e\u003cspan\u003e makes this example particularly attractive for vintage American production enthusiasts and for those seeking a period 12BH7A in authentic \u003c\/span\u003e\u003cstrong\u003e\u003cspan\u003eNOS NIB – New Old Stock, New In Box\u003c\/span\u003e\u003c\/strong\u003e\u003cspan\u003e condition.\u003c\/span\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cspan\u003eThe tube underwent \u003c\/span\u003e\u003cstrong\u003e\u003cspan\u003e48 hours of burn-in \/ stability test\u003c\/span\u003e\u003c\/strong\u003e\u003cspan\u003e and was subsequently carefully tested in our laboratory using the \u003c\/span\u003e\u003cstrong\u003e\u003cspan\u003eAmplitrex AT-1000 Tube Tester\u003c\/span\u003e\u003c\/strong\u003e\u003cspan\u003e, achieving a \u003c\/span\u003e\u003cstrong\u003e\u003cspan\u003eVERY STRONG\u003c\/span\u003e\u003c\/strong\u003e\u003cspan\u003e classification. Both sections show transconductance values higher than the nominal reference, with \u003c\/span\u003e\u003cstrong\u003e\u003cspan\u003eGm 3700 and 3300\u003c\/span\u003e\u003c\/strong\u003e\u003cspan\u003e compared to a 100% value of 3100, confirming particularly vigorous and stable emission. The tube was also found to be \u003c\/span\u003e\u003cstrong\u003e\u003cspan\u003eLow Noise \u0026amp; Microphonics\u003c\/span\u003e\u003c\/strong\u003e\u003cspan\u003e, with no shorts, gas, or detected anomalies.\u003c\/span\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cspan\u003eThe sections do not have a sufficiently strict balance for applications requiring perfect symmetry. The tube is therefore particularly suitable for \u003c\/span\u003e\u003cstrong\u003e\u003cspan\u003edriver stages, line stages, and other non-critical audio positions\u003c\/span\u003e\u003c\/strong\u003e\u003cspan\u003e, as well as for guitar amplifiers, while it is not the ideal choice as a \u003c\/span\u003e\u003cstrong\u003e\u003cspan\u003ephase inverter\u003c\/span\u003e\u003c\/strong\u003e\u003cspan\u003e when a strict balance between sections is required.\u003c\/span\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cspan\u003eSonically, American RCA Black Plates from this period are appreciated for rich, authoritative, and musical reproduction, with solid and well-structured bass, a full and natural midrange, and clean and refined high frequencies. The overall character combines the typical musicality of the best vintage RCA productions with the dynamics and driving capability characteristic of the 12BH7A.\u003c\/span\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cspan\u003eThe tube is \u003c\/span\u003e\u003cstrong\u003e\u003cspan\u003eNOS NIB – New Old Stock, New In Box\u003c\/span\u003e\u003c\/strong\u003e\u003cspan\u003e, carefully tested and fully functional, supplied in its \u003c\/span\u003e\u003cstrong\u003e\u003cspan\u003eoriginal RCA box\u003c\/span\u003e\u003c\/strong\u003e\u003cspan\u003e. The aesthetic conditions are good, with partially eroded but still legible silk-screening and a well-preserved tube body.\u003c\/span\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cspan\u003eA fascinating and uncommon \u003c\/span\u003e\u003cstrong\u003e\u003cspan\u003eRCA 12BH7A Black Plates Dimpled D-Foil Getter Made in USA\u003c\/span\u003e\u003c\/strong\u003e\u003cspan\u003e, genuinely tested and selected by \u003c\/span\u003e\u003cstrong\u003e\u003cspan\u003eVacuum Tubes Treasures\u003c\/span\u003e\u003c\/strong\u003e\u003cspan\u003e, ideal for those seeking authentic 1950s American RCA production, NOS, very strong, and selected \u003c\/span\u003e\u003cstrong\u003e\u003cspan\u003eLow Noise \u0026amp; Microphonics\u003c\/span\u003e\u003c\/strong\u003e\u003cspan\u003e.\u003c\/span\u003e\u003c\/p\u003e\n\u003ch3\u003e\u003cspan class=\"s1\"\u003e\u003cb\u003eCondition\u003c\/b\u003e\u003c\/span\u003e\u003c\/h3\u003e\n\u003cul\u003e\n\n\u003cli class=\"p3\"\u003e\n\n\u003cb\u003eCondition:\u003c\/b\u003e NOS - NIB - New Old Stock, New In Box - Tested and working - Supplied in Original box.\u003c\/li\u003e\n\n\u003cli class=\"p3\"\u003e\n\n\u003cb\u003eFunctionality:\u003c\/b\u003e Fully operational.\u003c\/li\u003e\n\n\u003cli class=\"p3\"\u003e\n\n\u003cb\u003eCosmetic condition:\u003c\/b\u003e Good – Partially eroded inscriptions, but still legible. Tube body in good condition. See photos for details.\u003c\/li\u003e\n\n\u003cli class=\"p2\"\u003e\n\n\u003cb\u003eManufacturing Code:\u003c\/b\u003e Code not decipherable. Production tentatively attributable to the 1950s based on construction characteristics.\u003c\/li\u003e\n\n\n\u003c\/ul\u003e\n\u003cp\u003e\u003cspan class=\"s2\"\u003e\u003cmeta charset=\"utf-8\"\u003e \u003ca href=\"https:\/\/vacuumtubestreasures.com\/blogs\/notizie\/perche-le-nostre-valvole-sono-diverse\" title=\"Why our tubes are different – the VTT protocol that improves sound, reliability and durability\" rel=\"noopener\" target=\"_blank\"\u003e\u003cstrong\u003eDiscover why our tubes are different →\u003c\/strong\u003e\u003c\/a\u003e\u003c\/span\u003e\u003c\/p\u003e","brand":"RCA","offers":[{"title":"Default Title","offer_id":58858486399324,"sku":"03765Y","price":833.0,"currency_code":"HKD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0616\/3775\/5127\/files\/1_86262fa0-1c44-4799-9841-8eda0797d5ad.jpg?v=1787938147","url":"https:\/\/vacuumtubestreasures.com\/en-hk\/products\/12bh7a-rca-nos-nib-black-plates-foil-dimpled-getter-usa-1950s-amplitrex-tested","provider":"Vacuum Tubes Treasures","version":"1.0","type":"link"}