{"product_id":"6550-tung-sol-type-2-4th-generation-amplitrex-matched-pair-very-strong-made-in-usa","title":"6550 TUNG-SOL Type 2 – 4th Generation - AMPLITREX Matched Pair - Made in USA","description":"\u003cp\u003e\u003cmeta charset=\"utf-8\"\u003e \u003cstrong\u003e6550 TUNG-SOL Type 2 - 4th Generation Gray Plates Triple Halo Getter Three Holes Matched Pair Tubes MADE IN USA\u003c\/strong\u003e\u003c\/p\u003e\n\u003ch3\u003e\u003cstrong\u003eDescription:\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cp data-start=\"386\" data-end=\"909\"\u003eThis \u003cstrong data-start=\"393\" data-end=\"437\"\u003ematched pair of 6550 Tung-Sol\u003c\/strong\u003e , Made in USA, belongs to the \u003cstrong data-start=\"468\" data-end=\"495\"\u003eType 2 – 4th generation\u003c\/strong\u003e , one of the most mature and musically balanced versions of the historic American 6550.\u003cbr data-start=\"583\" data-end=\"586\"\u003eThe construction with \u003cstrong data-start=\"605\" data-end=\"620\"\u003egray plates\u003c\/strong\u003e , \u003cstrong data-start=\"622\" data-end=\"644\"\u003etriple halo getter\u003c\/strong\u003e and \u003cstrong data-start=\"647\" data-end=\"675\"\u003ethree ventilation holes\u003c\/strong\u003e reflects a production phase oriented towards maximum electrical stability, controlled thermal dissipation and long operational reliability, maintaining intact the authoritative sound character typical of the best vintage 6550s.\u003c\/p\u003e\n\u003cp data-start=\"911\" data-end=\"1259\"\u003eThe set was \u003cstrong data-start=\"926\" data-end=\"959\"\u003eselected as a Matched pair\u003c\/strong\u003e and tested with professional equipment, proving to be \u003cstrong data-start=\"1015\" data-end=\"1030\"\u003eVERY STRONG\u003c\/strong\u003e , with homogeneous behavior and coherent response.\u003cbr data-start=\"1099\" data-end=\"1102\"\u003eThis is a pair designed for medium-high and high-end amplifiers, where balance, control and tonal solidity are fundamental requirements.\u003c\/p\u003e\n\u003chr data-start=\"1261\" data-end=\"1264\"\u003e\n\u003ch3 data-start=\"1266\" data-end=\"1286\"\u003eSound Character\u003c\/h3\u003e\n\u003cp data-start=\"1288\" data-end=\"1487\"\u003e\u003cstrong data-start=\"1288\" data-end=\"1297\"\u003eBass\u003c\/strong\u003e\u003cbr data-start=\"1297\" data-end=\"1300\"\u003eDeep, compact, and perfectly controlled. The low end is authoritative but never intrusive, with excellent articulation and the ability to sustain complex loads without losing definition.\u003c\/p\u003e\n\u003cp data-start=\"1489\" data-end=\"1677\"\u003e\u003cstrong data-start=\"1489\" data-end=\"1497\"\u003eMedium\u003c\/strong\u003e\u003cbr data-start=\"1497\" data-end=\"1500\"\u003eBalanced, full, and natural. The vocals are solid and well-focused, with a rich yet composed harmonic texture. They perform excellently on jazz, classic rock, and orchestral repertoire.\u003c\/p\u003e\n\u003cp data-start=\"1679\" data-end=\"1866\"\u003e\u003cstrong data-start=\"1679\" data-end=\"1687\"\u003eHigh\u003c\/strong\u003e \u003cbr data-start=\"1687\" data-end=\"1690\"\u003eClean, extended, and uncluttered. The highs are present but never aggressive, with a balance that favors prolonged listening and delivers air and detail without fatiguing.\u003c\/p\u003e\n\u003cp data-start=\"1868\" data-end=\"2017\"\u003e\u003cstrong data-start=\"1868\" data-end=\"1880\"\u003eDynamics\u003c\/strong\u003e\u003cbr data-start=\"1880\" data-end=\"1883\"\u003eConvincing and stable. Transient response is prompt yet controlled, with a sense of always-available power reserves.\u003c\/p\u003e\n\u003cp data-start=\"2019\" data-end=\"2175\"\u003e\u003cstrong data-start=\"2019\" data-end=\"2033\"\u003eSoundstage\u003c\/strong\u003e\u003cbr data-start=\"2033\" data-end=\"2036\"\u003eWide and well-structured, with a solid and credible soundstage. Excellent separation of levels and stable imaging even at high volumes.\u003c\/p\u003e\n\u003chr data-start=\"2177\" data-end=\"2180\"\u003e\n\u003ch3 data-start=\"2182\" data-end=\"2215\"\u003e🎧 Use in Hi-Fi Amplifiers\u003c\/h3\u003e\n\u003cp data-start=\"2216\" data-end=\"2227\"\u003eIdeal for:\u003c\/p\u003e\n\u003cul\u003e\n\u003cli data-start=\"2230\" data-end=\"2262\"\u003e6550 push-pull amplifiers\u003c\/li\u003e\n\u003cli data-start=\"2265\" data-end=\"2305\"\u003efinal and integrated courses in American schools\u003c\/li\u003e\n\u003cli data-start=\"2308\" data-end=\"2383\"\u003esystems that require \u003cstrong data-start=\"2331\" data-end=\"2371\"\u003ebalance, control and reliability\u003c\/strong\u003e over time\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp data-start=\"2385\" data-end=\"2525\"\u003eAn excellent choice for those who want the classic 6550 sound in a more modern and balanced version than the very first generations.\u003c\/p\u003e\n\u003chr data-start=\"2527\" data-end=\"2530\"\u003e\n\u003ch3 data-start=\"2532\" data-end=\"2567\"\u003e🎸 Use in Music Applications\u003c\/h3\u003e\n\u003cp data-start=\"2568\" data-end=\"2583\"\u003eAppreciated for:\u003c\/p\u003e\n\u003cul\u003e\n\u003cli data-start=\"2586\" data-end=\"2638\"\u003ehigh-powered bass and guitar amplifiers\u003c\/li\u003e\n\u003cli data-start=\"2641\" data-end=\"2732\"\u003eprofessional applications where stability, headroom and predictable response are required\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp data-start=\"2734\" data-end=\"2825\"\u003eThey offer a solid, defined and resistant sound even under demanding conditions of use.\u003c\/p\u003e\n\u003chr data-start=\"2827\" data-end=\"2830\"\u003e\n\u003ch3 data-start=\"2832\" data-end=\"2869\"\u003e🎯 Note for audiophiles and technicians\u003c\/h3\u003e\n\u003cp data-start=\"2870\" data-end=\"2953\"\u003eThis \u003cstrong data-start=\"2877\" data-end=\"2940\"\u003eMatched Pair of 6550 Tung-Sol Type 2 – 4th Generation\u003c\/strong\u003e represents:\u003c\/p\u003e\n\u003cul\u003e\n\u003cli data-start=\"2956\" data-end=\"3033\"\u003eone of the most reliable and musically balanced versions of the 6550 USA\u003c\/li\u003e\n\u003cli data-start=\"3036\" data-end=\"3094\"\u003eRobust construction with triple halo getters and gray plates\u003c\/li\u003e\n\u003cli data-start=\"3097\" data-end=\"3125\"\u003eaccurate matched selection\u003c\/li\u003e\n\u003cli data-start=\"3128\" data-end=\"3146\"\u003eVERY STRONG test\u003c\/li\u003e\n\u003cli data-start=\"3149\" data-end=\"3231\"\u003eexcellent compromise between \u003cstrong data-start=\"3176\" data-end=\"3231\"\u003esound performance, durability and collectible value\u003c\/strong\u003e\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp data-start=\"3233\" data-end=\"3388\" data-is-last-node=\"\" data-is-only-node=\"\"\u003eAn ideal pair for those looking for \u003cstrong data-start=\"3267\" data-end=\"3360\"\u003ereal performance, tonal coherence and the authentic character of the great American 6550s\u003c\/strong\u003e , without unnecessary compromises.\u003c\/p\u003e\n\u003chr\u003e\n\u003ch3\u003e\u003cstrong\u003eTest Results:\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cp\u003eTested on \u003cstrong\u003eAMPLITREX AT-1000\u003c\/strong\u003e Tube tester: \u003cbr\u003e\u003cstrong\u003eTest Conditions:\u003c\/strong\u003e Va = 450V ; Vg2 = 300V ; Vg = -30V\u003cbr\u003eMeasurements are taken after 10 minutes of preheating the tubes.\u003cbr\u003e\u003cstrong\u003eAverage 100%:\u003c\/strong\u003e Gm = 6.50 ; Ia = 50 mA\u003cbr\u003e\u003cstrong\u003eTEST RESULT:\u003c\/strong\u003e VERY STRONG\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eValve 1:\u003c\/strong\u003e Gm = 5.22 ; Ia = 43 mA\u003cbr\u003e\u003cstrong\u003eValve 2:\u003c\/strong\u003e Gm = 5.25 ; Ia = 47 mA\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eAdditional Tests Performed:\u003c\/strong\u003e\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003e\u003cspan\u003e\u003cstrong\u003eMicrophonics:\u003c\/strong\u003e\u003cmeta charset=\"utf-8\"\u003e Standard. Tested and approved for use in hi-fi and guitar amplifiers.\u003c\/span\u003e\u003c\/li\u003e\n\u003cli\u003e\u003cspan\u003e\u003cstrong\u003eOutput Quality:\u003c\/strong\u003e Excellent – Very strong and stable output, no fluctuations.\u003c\/span\u003e\u003c\/li\u003e\n\u003cli\u003e\u003cspan\u003e\u003cstrong\u003eShort circuits and GAS:\u003c\/strong\u003e 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\u003eCondition:\u003c\/strong\u003e Vintage tubes - Tested and in perfect working order. Shipped in our custom box for optimal protection.\u003cstrong\u003e\u003cbr\u003e\u003c\/strong\u003e\u003c\/li\u003e\n\u003cli\u003e\u003cstrong\u003eFunctionality:\u003c\/strong\u003e Fully functional.\u003cstrong\u003e\u003cbr\u003e\u003c\/strong\u003e\u003c\/li\u003e\n\u003cli\u003e\u003cstrong\u003eAesthetic conditions:\u003c\/strong\u003e \u003cmeta charset=\"utf-8\"\u003eGood. One of the two tubes has \u003cstrong data-end=\"517\" data-start=\"456\"\u003ecompletely faded writing on the base\u003c\/strong\u003e , while the \u003cstrong data-end=\"591\" data-start=\"529\"\u003eflash getter of one tube is visually irregular\u003c\/strong\u003e . The \u003cstrong data-end=\"640\" data-start=\"600\"\u003eglass body is in good condition\u003c\/strong\u003e , with intact structure. The aspects described are \u003cstrong data-end=\"746\" data-start=\"709\"\u003epurely aesthetic in nature\u003c\/strong\u003e and \u003cstrong data-end=\"841\" data-start=\"749\"\u003edo not affect the electrical operation, safety, or sonic performance\u003c\/strong\u003e . See photos for details.\u003cstrong\u003e\u003cbr\u003e\u003c\/strong\u003e\u003c\/li\u003e\n\u003cli\u003e\u003cstrong\u003eManufacturing Code:\u003c\/strong\u003e\u003cmeta charset=\"utf-8\"\u003e \u003cspan\u003e3226432-3 →\u003c\/span\u003e \u003cstrong\u003e322\u003c\/strong\u003e \u003cspan\u003eindicates the manufacturer, i.e. Tung-Sol Electric Inc., Newark 4, NJ -\u003c\/span\u003e \u003cstrong\u003e64\u003c\/strong\u003e \u003cspan\u003e→ 1964 -\u003c\/span\u003e \u003cstrong\u003e32\u003c\/strong\u003e \u003cspan\u003e→ 32nd week of the year\u003c\/span\u003e\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp\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\u003eFind out why our valves are different →\u003c\/strong\u003e\u003c\/a\u003e\u003c\/p\u003e","brand":"TUNG-SOL","offers":[{"title":"Default Title","offer_id":56500805337436,"sku":"03371","price":429.0,"currency_code":"EUR","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0616\/3775\/5127\/files\/3_010b0a49-3648-4b73-8bc7-f1ba9826074d.jpg?v=1768847101","url":"https:\/\/vacuumtubestreasures.com\/en-hr\/products\/6550-tung-sol-type-2-4th-generation-amplitrex-matched-pair-very-strong-made-in-usa","provider":"Vacuum Tubes Treasures","version":"1.0","type":"link"}