{"product_id":"6550-jj-matched-quad-amplitrex-tested-tubes-new-4-valvole-in-original-box","title":"6550 JJ Matched Quad - AMPLITREX Tested Tubes - NEW - 4 Valves IN ORIGINAL BOX","description":"\u003cp\u003e\u003cstrong\u003e6550 JJ Matched Quad AMPLITREX Tested Tubes (4 Valves) NEW - IN ORIGINAL BOX\u003c\/strong\u003e\u003c\/p\u003e\n\n\u003cp\u003e \u003cstrong\u003eMADE IN SLOVAK REPUBLIC\u003c\/strong\u003e\u003c\/p\u003e\n\n\u003cp data-start=\"105\" data-end=\"613\"\u003e The \u003cstrong\u003e6550 JJ\u003c\/strong\u003e represents one of the most appreciated modern power tubes for balance, reliability and dynamic handling.\u003cbr\u003e Designed to deliver consistent performance and full, musical sound, they are individually tested in our lab with \u003cstrong\u003eAmplitrex AT-1000\u003c\/strong\u003e at real operating voltages, to ensure \u003cstrong\u003eaccurate static matching\u003c\/strong\u003e on anode current (Ia) and transconductance (Gm).\u003cbr\u003e Each quartet is selected and electrically verified to offer stability, symmetry and long operating life.\u003c\/p\u003e\n\n\u003cp data-start=\"615\" data-end=\"971\"\u003e \u003cstrong\u003eSelection Process – Technical Check and Sound Consistency\u003c\/strong\u003e\u003c\/p\u003e\n\n\u003cul\u003e\n\n\u003cli data-start=\"615\" data-end=\"971\"\u003e Testing the \u003cstrong\u003eAmplitrex AT-1000\u003c\/strong\u003e at real-world operating voltages\u003cbr\u003e\u003cstrong\u003e\u003c\/strong\u003e\n\n\u003c\/li\u003e\n\n\u003cli data-start=\"615\" data-end=\"971\"\u003e\n\n \u003cstrong\u003eStatic matching\u003c\/strong\u003e on main parameters (Ia \/ Gm)\u003cbr\u003e\n\n\u003c\/li\u003e\n\n\u003cli data-start=\"615\" data-end=\"971\"\u003e Measurements taken after 10 minutes of preheating\u003cbr\u003e\n\n\u003c\/li\u003e\n\n \u003cli data-start=\"615\" data-end=\"971\"\u003e\n\u003cstrong\u003eMicrophony, emission and isolation\u003c\/strong\u003e control\u003cbr\u003e\n\n\u003c\/li\u003e\n\n\u003cli data-start=\"615\" data-end=\"971\"\u003e Packaged in original box, sealed to ensure authenticity\u003c\/li\u003e\n\n\n\u003c\/ul\u003e\n\n\u003cp data-start=\"973\" data-end=\"1619\"\u003e \u003cstrong\u003eSound characteristics\u003c\/strong\u003e\u003c\/p\u003e\n\n\u003cul\u003e\n\n\u003cli data-start=\"973\" data-end=\"1619\"\u003e\n\n \u003cstrong\u003eBass:\u003c\/strong\u003e solid and tight, with excellent control and articulation. Precise rhythmic foundation, never intrusive.\u003c\/li\u003e\n\n\u003cli data-start=\"973\" data-end=\"1619\"\u003e\n\n \u003cstrong\u003eMids:\u003c\/strong\u003e natural and transparent, with balanced timbre and realism in the voices.\u003c\/li\u003e\n\n\u003cli data-start=\"973\" data-end=\"1619\"\u003e\n\n \u003cstrong\u003eHighs:\u003c\/strong\u003e extended and clean, with harmoniously integrated brilliance and no harshness.\u003c\/li\u003e\n\n\u003cli data-start=\"973\" data-end=\"1619\"\u003e\n\n \u003cstrong\u003eDynamics:\u003c\/strong\u003e prompt and stable, with fluid response and control even at high volumes.\u003c\/li\u003e\n\n\u003cli data-start=\"973\" data-end=\"1619\"\u003e\n\n \u003cstrong\u003eSoundstage:\u003c\/strong\u003e wide and coherent, with good depth and centered soundstage.\u003c\/li\u003e\n\n\n\u003c\/ul\u003e\n\n\u003cp data-start=\"973\" data-end=\"1619\"\u003e \u003cstrong\u003e🎧 Ideal for medium and high-end Hi-Fi systems, where balance and musicality are sought.\u003c\/strong\u003e\u003c\/p\u003e\n\n\u003cp data-start=\"973\" data-end=\"1619\"\u003e \u003cstrong\u003e🎸 Excellent for musical amplifiers requiring power, headroom and progressive dynamic response.\u003c\/strong\u003e\u003c\/p\u003e\n\n\u003cp data-start=\"1621\" data-end=\"1688\"\u003e \u003cstrong\u003eTest Specifications\u003c\/strong\u003e\u003c\/p\u003e\n\n\u003cul\u003e\n\n\u003cli data-start=\"1621\" data-end=\"1688\"\u003e Valves tested on \u003cstrong\u003eAmplitrex AT-1000\u003c\/strong\u003e Tube Tester\u003c\/li\u003e\n\n \u003cli data-start=\"1690\" data-end=\"1747\"\u003e\u003cstrong\u003eMeasurements taken after 10 minutes of preheating\u003c\/strong\u003e\u003c\/li\u003e\n\n\n\u003c\/ul\u003e\n\n\u003cp data-start=\"1749\" data-end=\"1775\"\u003e \u003cstrong\u003eAdditional Tests Performed:\u003c\/strong\u003e\u003c\/p\u003e\n\n\u003cul\u003e\n\n\u003cli data-start=\"1777\" data-end=\"2087\"\u003e\n\n \u003cstrong\u003eMicrophonics:\u003c\/strong\u003e Standard – compliant for use in hi-fi and music amplifiers.\u003c\/li\u003e\n\n\u003cli data-start=\"1777\" data-end=\"2087\"\u003e\n\n \u003cstrong\u003eOutput quality:\u003c\/strong\u003e excellent – ​​strong, stable and smooth output.\u003cbr\u003e\n\n\u003c\/li\u003e\n\n\u003cli data-start=\"1777\" data-end=\"2087\"\u003e\n\n \u003cstrong\u003eShort circuits and GAS:\u003c\/strong\u003e absent.\u003cbr\u003e\n\n\u003c\/li\u003e\n\n\n\u003c\/ul\u003e\n\n\u003cp data-start=\"1777\" data-end=\"2087\"\u003e Our 6550 JJ valves are tested and matched to real static parameters, ensuring consistency and reliability over time.\u003c\/p\u003e\n\n\u003cp data-start=\"2089\" data-end=\"2552\"\u003e \u003cstrong\u003eConditions\u003c\/strong\u003e\u003cbr\u003e Supplied in our original box.\u003cbr\u003e Functionality: impeccable.\u003cbr\u003e Factory new valves, tested and in perfect working order.\u003cbr\u003e 24-month legal guarantee (consumers, Legislative Decree 206\/2005). B2B: Articles 1490 et seq. of the Italian Civil Code apply.\u003cbr\u003e Returns for sound preferences\/tube rolling are not accepted. 14-day returns only with intact seal and unused tube.\u003cbr\u003e The warranty covers only original defects in conformity; wear and tear, improper use, and tampering are excluded.\u003c\/p\u003e\n\n\u003cp data-start=\"2905\" data-end=\"3055\"\u003e \u003cstrong\u003eAdditional Information\u003c\/strong\u003e \u003cbr\u003eJJ tubes may exhibit slight variations in glass bulb height, with no impact on performance. \u003c\/p\u003e\n\n\u003cp data-start=\"3058\" data-end=\"3161\" data-is-last-node=\"\" data-is-only-node=\"\"\u003e\u003cmeta charset=\"utf-8\"\u003e \u003cspan style=\"color: rgb(43, 0, 255);\"\u003e\u003cstrong\u003eFAQ - Frequently Asked Questions:\u003c\/strong\u003e\u003c\/span\u003e\u003c\/p\u003e\n\n\u003cul\u003e\n\n\u003cli\u003e\n\n \u003cstrong\u003eRequest:\u003c\/strong\u003e\u003cspan\u003e \u003c\/span\u003eAfter installation, do they sound loud right away? Or do they need to be broken in?\u003cbr\u003e\n\n\u003c\/li\u003e\n\n\u003cli\u003e\n\n \u003cstrong\u003eAnswer:\u003c\/strong\u003e\u003cspan\u003e \u003c\/span\u003eThey sound good right out of the box, but they get better with time. After just 50 hours, the bass becomes tight, and around 100 hours, the tonal balance stabilizes. Breaking in is part of the process that makes the sound more natural and engaging.\u003c\/li\u003e\n\n\n\u003c\/ul\u003e\n\n\u003cp\u003e\u003cmeta charset=\"utf-8\"\u003e 🔍 Find out what we really think: \u003ca rel=\"noopener\" title=\"Complete Guide to the 6550 JJ Valve\" href=\"https:\/\/vacuumtubestreasures.com\/blogs\/notizie\/guida-completa-alla-valvola-6550-jj\" target=\"_blank\"\u003eread our complete guide to the 6550 JJ.\u003c\/a\u003e\u003c\/p\u003e","brand":"JJ ELECTRONICS","offers":[{"title":"Default Title","offer_id":55705039765852,"sku":"03194","price":229.0,"currency_code":"EUR","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0616\/3775\/5127\/files\/1_6664b52a-f20a-47a2-bb4d-a5da81c8dd70.jpg?v=1760259409","url":"https:\/\/vacuumtubestreasures.com\/en-hr\/products\/6550-jj-matched-quad-amplitrex-tested-tubes-new-4-valvole-in-original-box","provider":"Vacuum Tubes Treasures","version":"1.0","type":"link"}