{"product_id":"5751-rca-triple-mica-black-plates-square-getter-amplitrex-tested-tube-usa","title":"5751 RCA Triple Mica Black Plates Square Getter Amplitrex Tested Tube USA","description":"\u003cp\u003e\u003cstrong\u003e5751 RCA Triple Mica Black Plates Square Getter Made in USA '50s\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eLow Noise \u0026amp; Microphonics –\u003cspan\u003e VERY STRONG - Balanced Sections - Vintage American RCA Production\u003c\/span\u003e\u003c\/strong\u003e\u003c\/p\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\n\u003cli\u003e\n\n\u003cstrong\u003eTest Conditions:\u003c\/strong\u003e\u003cspan\u003e Va = 250V ; Vg = -3V\u003c\/span\u003e\n\n\u003c\/li\u003e\n\n\u003cli\u003e\n\n\u003cstrong\u003e100% Average:\u003c\/strong\u003e\u003cspan\u003e \u003c\/span\u003eGm = 1200 ; Ia = 1.0 mA\u003c\/li\u003e\n\n\u003cli\u003e\n\n\u003cstrong\u003eTest Result:\u003c\/strong\u003e VERY STRONG\u003c\/li\u003e\n\n\n\u003c\/ul\u003e\n\u003cp\u003e\u003cstrong\u003eTube :\u003c\/strong\u003e\u003c\/p\u003e\n\u003cul\u003e\n\n\u003cli\u003e\n\n\u003cstrong\u003eSection 1:\u003c\/strong\u003e\u003cspan\u003e \u003c\/span\u003eGm = 1400 ; Ia = 1.7 mA\u003c\/li\u003e\n\n\u003cli\u003e\n\n\u003cstrong\u003eSection 2:\u003c\/strong\u003e\u003cspan\u003e \u003c\/span\u003eGm = 1400 ; Ia = 1.6 mA\u003c\/li\u003e\n\n\n\u003c\/ul\u003e\n\u003cdiv\u003e\n\n\u003cmeta charset=\"utf-8\"\u003e\n\n\u003cdiv\u003e\u003cstrong\u003eAdditional tests performed:\u003c\/strong\u003e\u003c\/div\u003e\n\n\u003cul\u003e\n\n\u003cli\u003e\u003cspan\u003e\u003cstrong\u003eBurn-in \/ Stability Test: \u003c\/strong\u003e48h – OK\u003c\/span\u003e\u003c\/li\u003e\n\n\u003cli\u003e\u003cspan\u003e\u003cstrong\u003eMicrophonics:\u003c\/strong\u003e Low. Tested and compliant for use in hi-fi equipment and guitar amplifiers, even in the most sensitive audio stages.\u003c\/span\u003e\u003c\/li\u003e\n\n\u003cli\u003e\u003cspan\u003e\u003cstrong\u003eBalance:\u003c\/strong\u003e Very good. The sections are consistent and well-aligned, making the tube also suitable for use as a phase inverter in hi-fi and instrumental applications.\u003c\/span\u003e\u003c\/li\u003e\n\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\n\u003cli\u003e\u003cspan\u003e\u003cstrong\u003eShorts and GAS:\u003c\/strong\u003e None.\u003c\/span\u003e\u003c\/li\u003e\n\n\n\u003c\/ul\u003e\n\n\n\u003c\/div\u003e\n\u003ch3\u003e\u003cstrong\u003eDescription:\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cp data-pm-slice=\"1 1 []\"\u003e\u003cspan\u003eThis \u003c\/span\u003e\u003cstrong\u003e\u003cspan\u003e5751 RCA Triple Mica Black Plates\u003c\/span\u003e\u003c\/strong\u003e\u003cspan\u003e is a particularly interesting example of American tube production attributable to the 1950s. The internal construction features \u003c\/span\u003e\u003cstrong\u003e\u003cspan\u003eblack plates, a triple mica spacer, and a square getter\u003c\/span\u003e\u003c\/strong\u003e\u003cspan\u003e, a robust and recognizable configuration developed to ensure mechanical stability and operational reliability.\u003c\/span\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cspan\u003eThe manufacturing code and external silkscreen prints are no longer visible; the attribution to RCA production and the indicated period is therefore based on the construction characteristics of the specimen. Despite signs of age and the absence of markings, the internal structure is intact, well-preserved, and clearly documented in the photographs.\u003c\/span\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cspan\u003eAfter a \u003c\/span\u003e\u003cstrong\u003e\u003cspan\u003e48-hour burn-in\u003c\/span\u003e\u003c\/strong\u003e\u003cspan\u003e cycle, the tube was tested with an \u003c\/span\u003e\u003cstrong\u003e\u003cspan\u003eAmplitrex AT-1000\u003c\/span\u003e\u003c\/strong\u003e\u003cspan\u003e, recording \u003c\/span\u003e\u003cstrong\u003e\u003cspan\u003eGm 1400 in both sections\u003c\/span\u003e\u003c\/strong\u003e\u003cspan\u003e, with anode currents of \u003c\/span\u003e\u003cstrong\u003e\u003cspan\u003e1.7 and 1.6 mA\u003c\/span\u003e\u003c\/strong\u003e\u003cspan\u003e respectively. The transconductance values exceed the nominal reference and confirm \u003c\/span\u003e\u003cstrong\u003e\u003cspan\u003every strong, stable emission free of fluctuations\u003c\/span\u003e\u003c\/strong\u003e\u003cspan\u003e.\u003c\/span\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cspan\u003eThe \u003c\/span\u003e\u003cstrong\u003e\u003cspan\u003eexcellent balance\u003c\/span\u003e\u003c\/strong\u003e\u003cspan\u003e is one of the main strengths of this specimen. The two sections present the same Gm value and nearly identical anode currents, making the tube also suitable as a \u003c\/span\u003e\u003cstrong\u003e\u003cspan\u003ephase inverter\u003c\/span\u003e\u003c\/strong\u003e\u003cspan\u003e, as well as a driver or in stages where uniformity and good symmetry are required.\u003c\/span\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cspan\u003eThe selection for \u003c\/span\u003e\u003cstrong\u003e\u003cspan\u003elow noise and microphonics\u003c\/span\u003e\u003c\/strong\u003e\u003cspan\u003e allows it to be used even in the most sensitive audio stages of hi-fi equipment and guitar amplifiers. From a sonic perspective, this RCA production is appreciated for a \u003c\/span\u003e\u003cstrong\u003e\u003cspan\u003efull-bodied, musical, and natural\u003c\/span\u003e\u003c\/strong\u003e\u003cspan\u003e performance, with a rich midrange, present bass, and smooth, well-integrated high frequencies.\u003c\/span\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cspan\u003eA \u003c\/span\u003e\u003cstrong\u003e\u003cspan\u003evintage 5751 Made in USA\u003c\/span\u003e\u003c\/strong\u003e\u003cspan\u003e of significant technical and historical interest, capable of combining Triple Mica construction, black plates, and a square getter, with emission above reference and perfectly balanced sections. Although it lacks markings and shows evident signs of age, the tube has been carefully tested, is perfectly operational, and is free of shorts or gas.\u003c\/span\u003e\u003c\/p\u003e\n\u003chr\u003e\n\u003ch3\u003e\u003cstrong\u003eConditions:\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cul\u003e\n\n\u003cli\u003e\n\n\u003cstrong\u003eCondition:\u003c\/strong\u003e Vintage Tubes - Tested and perfectly functional. Supplied in our custom box for optimal protection.\u003cstrong\u003e\u003cbr\u003e\u003c\/strong\u003e\n\n\u003c\/li\u003e\n\n\u003cli\u003e\n\n\u003cstrong\u003eFunctionality: \u003c\/strong\u003ePerfectly operational.\u003cstrong\u003e\u003cbr\u003e\u003c\/strong\u003e\n\n\u003c\/li\u003e\n\n\u003cli\u003e\n\n\u003cstrong\u003eCosmetic condition:\u003c\/strong\u003e Adequate – Markings absent, general aesthetic shows evident signs of age. See photos for details.\u003cstrong\u003e\u003cbr\u003e\u003c\/strong\u003e\n\n\u003c\/li\u003e\n\n\u003cli\u003e\n\n\u003cstrong\u003eManufacturing Code:\u003c\/strong\u003e Code absent. Production indicatively attributable to the 1950s based on construction characteristics.\u003c\/li\u003e\n\n\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":"RCA","offers":[{"title":"Default Title","offer_id":59589933597020,"sku":"03884","price":109.9,"currency_code":"EUR","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0616\/3775\/5127\/files\/2_5ac4c2b1-81ed-46f6-8cdf-70fef299aded.jpg?v=1792421194","url":"https:\/\/vacuumtubestreasures.com\/en-ee\/products\/5751-rca-triple-mica-black-plates-square-getter-amplitrex-tested-tube-usa","provider":"Vacuum Tubes Treasures","version":"1.0","type":"link"}