{"product_id":"6sn7gta-nos-sylvania-chrome-top-matched-pair-same-production-code-low-noise-microphonics-amplitrex-tested","title":"6SN7GTA NOS SYLVANIA Chrome Top Matched Pair - Same Production Code - Low Noise \u0026 Microphonics - AMPLITREX Tested","description":"\u003ch3 class=\"p1\"\u003e\u003cb\u003e6SN7GTA NOS SYLVANIA – \u003cmeta charset=\"utf-8\"\u003e \u003cspan\u003eShort \u003c\/span\u003e\u003cspan\u003eBase \u003c\/span\u003e\u003cspan\u003eChrome \u003c\/span\u003e\u003cspan\u003eTop\u003c\/span\u003e – Matched Pair – Same Data Codes – Made in USA 1955\u003c\/b\u003e\u003c\/h3\u003e\n\u003cp class=\"p1\"\u003e\u003cb\u003eAMPLITREX Tested – VERY STRONG – \u003cmeta charset=\"utf-8\"\u003e \u003cspan\u003eGreen Dot \u0026amp; Gray Dot \u003cmeta charset=\"utf-8\"\u003e– \u003c\/span\u003eLow Noise \u0026amp; Microphonics\u003c\/b\u003e\u003c\/p\u003e\n\u003ch3 data-start=\"3046\" data-end=\"3436\"\u003e\u003cstrong\u003eRisultati dei Test:\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cp\u003eValvole testate su \u003cstrong\u003eAmplitrex AT-1000 Tube tester\u003c\/strong\u003e:\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eCondizioni di Test:\u003c\/strong\u003e\u003cspan\u003e \u003c\/span\u003eVa = 250V, Vg = -8V\u003c\/li\u003e\n\u003cli\u003e\u003cstrong\u003eMedia 100% Gm = 2600 ; Ia = 9.0 mA\u003c\/strong\u003e\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eRisultato del Test:\u003c\/strong\u003e MOLTO FORTE\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp class=\"p1\"\u003e\u003cb\u003eValvola #36\u003c\/b\u003e\u003c\/p\u003e\n\u003cul\u003e\n\u003cli class=\"p1\"\u003eSezione 1: Gm = \u003cmeta charset=\"utf-8\"\u003e2700 ; Ia = 7.6 mA\u003c\/li\u003e\n\u003cli class=\"p1\"\u003eSezione 2: Gm = 2600 ; Ia = 7.0 mA\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp class=\"p1\"\u003e\u003cb\u003eValvola #9\u003c\/b\u003e\u003c\/p\u003e\n\u003cul\u003e\n\u003cli class=\"p1\"\u003eSezione 1: Gm = 2600 ; Ia = 7.6 mA\u003c\/li\u003e\n\u003cli class=\"p1\"\u003eSezione 2: Gm = 2700 ; Ia = 8.2 mA\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch3 class=\"p1\"\u003e\u003cb\u003eTest addizionali:\u003c\/b\u003e\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli class=\"p1\"\u003e\u003cspan class=\"s1\"\u003e\u003cb\u003eBurn-in \/ Stability Test:\u003c\/b\u003e 48h – OK\u003c\/span\u003e\u003c\/li\u003e\n\u003cli class=\"p1\"\u003e\n\u003cspan class=\"s1\"\u003e\u003cb\u003eMicrofonicità e rumore:\u003c\/b\u003e\u003c\/span\u003e Molto Bassi. Testate e conformi per l’impiego in apparecchiature hi-fi e amplificatori per chitarra, anche negli stadi audio più sensibili.\u003c\/li\u003e\n\u003cli class=\"p1\"\u003e\n\u003cspan class=\"s1\"\u003e\u003cb\u003eBilanciamento:\u003c\/b\u003e\u003c\/span\u003e Molto buono. Le sezioni risultano coerenti e ben allineate, rendendo la valvola idonea anche all’impiego come phase inverter in applicazioni hi-fi e strumentali.\u003c\/li\u003e\n\u003cli class=\"p1\"\u003e\n\u003cspan class=\"s1\"\u003e\u003cb\u003eEmissione:\u003c\/b\u003e\u003c\/span\u003e Eccellente – Emissione molto forte e stabile, senza fluttuazioni.\u003c\/li\u003e\n\u003cli class=\"p1\"\u003e\n\u003cb\u003eCortocircuiti \/ Gas:\u003c\/b\u003e\u003cspan class=\"s1\"\u003e assenti\u003c\/span\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch3 class=\"p1\"\u003e\u003cb\u003eDescrizione\u003c\/b\u003e\u003c\/h3\u003e\n\u003cp data-pm-slice=\"1 1 []\"\u003e\u003cspan\u003eEccezionale coppia NOS di \u003c\/span\u003e\u003cstrong\u003e\u003cspan\u003e6SN7GTA Sylvania\u003c\/span\u003e\u003c\/strong\u003e\u003cspan\u003e, prodotta negli Stati Uniti nel \u003c\/span\u003e\u003cstrong\u003e\u003cspan\u003e1955\u003c\/span\u003e\u003c\/strong\u003e\u003cspan\u003e e accuratamente selezionata come \u003c\/span\u003e\u003cstrong\u003e\u003cspan\u003eMatched Pair\u003c\/span\u003e\u003c\/strong\u003e\u003cspan\u003e. Entrambi gli esemplari condividono l'identico codice di fabbricazione \u003c\/span\u003e\u003cstrong\u003e\u003cspan\u003e288 \/ 513\u003c\/span\u003e\u003c\/strong\u003e\u003cspan\u003e, riconducibile alla 13ª settimana del 1955, e presentano la caratteristica costruzione \u003c\/span\u003e\u003cstrong\u003e\u003cspan\u003eShort Base Chrome Top\u003c\/span\u003e\u003c\/strong\u003e\u003cspan\u003e, espressione della rinomata produzione americana Sylvania degli anni ’50.\u003c\/span\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cspan\u003eLe misurazioni effettuate con \u003c\/span\u003e\u003cstrong\u003e\u003cspan\u003eAmplitrex AT-1000\u003c\/span\u003e\u003c\/strong\u003e\u003cspan\u003e evidenziano una transconduttanza compresa tra \u003c\/span\u003e\u003cstrong\u003e\u003cspan\u003e2600 e 2700 µmhos\u003c\/span\u003e\u003c\/strong\u003e\u003cspan\u003e, con una media di \u003c\/span\u003e\u003cstrong\u003e\u003cspan\u003e2650 µmhos per ciascuna valvola\u003c\/span\u003e\u003c\/strong\u003e\u003cspan\u003e, superiore al riferimento nominale di 2600. Le correnti anodiche variano da 7,0 a 8,2 mA, con medie rispettivamente di 7,3 e 7,9 mA, rispetto al riferimento di 9,0 mA. Risultati che confermano una transconduttanza molto forte e un \u003c\/span\u003e\u003cstrong\u003e\u003cspan\u003eabbinamento particolarmente uniforme\u003c\/span\u003e\u003c\/strong\u003e\u003cspan\u003e, con sezioni ben bilanciate e differenze contenute tra i due esemplari.\u003c\/span\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cspan\u003eLa selezione comprende \u003c\/span\u003e\u003cstrong\u003e\u003cspan\u003e48 ore di burn-in\u003c\/span\u003e\u003c\/strong\u003e\u003cspan\u003e, durante le quali è stata verificata la stabilità delle prestazioni, accompagnate da controlli che hanno confermato un'emissione forte e costante, senza cortocircuiti né presenza di gas. Particolare attenzione è stata dedicata al rumore e alla microfonicità, risultati molto bassi. La selezione speciale \u003c\/span\u003e\u003cstrong\u003e\u003cspan\u003eGreen Dot e Gray Dot\u003c\/span\u003e\u003c\/strong\u003e\u003cspan\u003e aggiunge valore a questa coppia, soprattutto per l'impiego negli stadi audio più sensibili.\u003c\/span\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cspan\u003eLe \u003c\/span\u003e\u003cstrong\u003e\u003cspan\u003e6SN7GTA Sylvania\u003c\/span\u003e\u003c\/strong\u003e\u003cspan\u003e trovano applicazione in preamplificatori hi-fi, stadi driver, amplificatori per cuffie e circuiti phase inverter compatibili. La produzione Sylvania di questo periodo è particolarmente apprezzata dagli appassionati di valvole vintage per una presentazione musicale generalmente descritta come \u003c\/span\u003e\u003cstrong\u003e\u003cspan\u003eaperta, equilibrata e ricca di dettaglio\u003c\/span\u003e\u003c\/strong\u003e\u003cspan\u003e, con una naturalezza espressiva che ne alimenta l'interesse nel mondo dell'audio a valvole.\u003c\/span\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cspan\u003eL'appartenenza alla \u003c\/span\u003e\u003cstrong\u003e\u003cspan\u003emedesima settimana di produzione del marzo 1955\u003c\/span\u003e\u003c\/strong\u003e\u003cspan\u003e, le marcature originali ottimamente conservate e l'eccellente stato estetico rendono questa coppia particolarmente interessante anche sotto il profilo storico. Un'opportunità per chi desidera autentiche \u003c\/span\u003e\u003cstrong\u003e\u003cspan\u003eSylvania NOS degli anni ’50\u003c\/span\u003e\u003c\/strong\u003e\u003cspan\u003e, con caratteristiche elettriche documentate, abbinamento accurato e una selezione pensata per valorizzarne le qualità nelle applicazioni audio più esigenti.\u003c\/span\u003e\u003c\/p\u003e\n\u003chr\u003e\n\u003ch3 class=\"p1\"\u003e\u003cstrong\u003eCondizioni\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli class=\"p1\"\u003e\n\u003cspan class=\"s1\"\u003e\u003cb\u003eCondizioni:\u003c\/b\u003e\u003c\/span\u003e NOS - New Old Stock - Testata e funzionante - Fornite in nostra scatola personalizzata per una protezione ottimale.\u003c\/li\u003e\n\u003cli class=\"p1\"\u003e\n\u003cspan class=\"s1\"\u003e\u003cb\u003eFunzionalità:\u003c\/b\u003e\u003c\/span\u003e Perfettamente operativa\u003c\/li\u003e\n\u003cli class=\"p1\"\u003e\n\u003cspan class=\"s1\"\u003e\u003cb\u003eCondizioni estetiche:\u003c\/b\u003e\u003c\/span\u003e Eccellenti – Scritte ottimamente conservate, minimi segni del tempo. Vedi foto per i dettagli.\u003c\/li\u003e\n\u003cli class=\"p1\"\u003e\n\u003cmeta charset=\"utf-8\"\u003e \u003cstrong\u003eSelezione \u003c\/strong\u003e\u003cspan\u003e\u003cstrong\u003especiale:\u003c\/strong\u003e \u003c\/span\u003e\u003cstrong\u003e\u003cmeta charset=\"utf-8\"\u003e\u003c\/strong\u003e\u003cspan\u003eGreen \u003c\/span\u003e\u003cspan\u003eDot \u003c\/span\u003e\u003cspan\u003ee \u003c\/span\u003e\u003cspan\u003eGray \u003c\/span\u003e\u003cspan\u003eDot, \u003c\/span\u003e\u003cspan\u003econ \u003c\/span\u003e\u003cspan\u003ebasso \u003c\/span\u003e\u003cspan\u003erumore \u003c\/span\u003e\u003cspan\u003ee \u003c\/span\u003e\u003cspan\u003emicrofonicità \u003c\/span\u003e\u003cspan\u003everificati \u003c\/span\u003e\u003cspan\u003emediante \u003c\/span\u003e\u003cspan\u003eAmplitrex \u003c\/span\u003e\u003cspan\u003eAT-1000.\u003c\/span\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eCodice di fabbricazione:\u003c\/strong\u003e Sylvania Electric Products Inc., USA – marcatura originale sulla base 288 \/ 513. 288 codice Sylvania Interno. 513 - 13ª settimana del 1955 (marzo 1955).\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\u003eScopra perché le nostre valvole sono diverse →\u003c\/strong\u003e\u003c\/a\u003e\u003c\/p\u003e","brand":"SYLVANIA","offers":[{"title":"Default Title","offer_id":59667516391772,"sku":"03903","price":4472.0,"currency_code":"CZK","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0616\/3775\/5127\/files\/7_6148e448-9f4d-4bc2-80a1-fd5d3c63a857.jpg?v=1793178561","url":"https:\/\/vacuumtubestreasures.com\/it-cz\/products\/6sn7gta-nos-sylvania-chrome-top-matched-pair-same-production-code-low-noise-microphonics-amplitrex-tested","provider":"Vacuum Tubes Treasures","version":"1.0","type":"link"}