{"product_id":"7189-sherwood-by-philips-heerlen-1963-gray-plates-δx4-matched-quad-tested-100","title":"7189 SHERWOOD by Philips – Heerlen 1963 – Gray Plates – rx4 – Matched Quad – Tested 100%","description":"\u003cp\u003e\u003cmeta charset=\"utf-8\"\u003e\u003cstrong\u003e7189 SHERWOOD by Philips – Heerlen 1963 – Gray Plates – rx4 – Matched Quad – Tested 100% - Made in HOLLAND\u003c\/strong\u003e\u003c\/p\u003e\n\u003ch3\u003e\u003cstrong\u003eDescription:\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cp data-start=\"0\" data-end=\"769\"\u003eThis \u003cstrong data-start=\"37\" data-end=\"86\"\u003ematched quartet of 7189 Sherwood by Philips\u003c\/strong\u003e , produced \u003cstrong data-start=\"99\" data-end=\"124\"\u003ein Heerlen (Holland) in 1963\u003c\/strong\u003e , belongs to the prestigious line made by Philips for Sherwood, one of the most reliable and musical combinations of the time.\u003cbr data-start=\"256\" data-end=\"259\"\u003eThis is the \u003cstrong data-start=\"284\" data-end=\"299\"\u003egray plates\u003c\/strong\u003e variant with factory coding \u003cstrong data-start=\"322\" data-end=\"329\"\u003erX4\u003c\/strong\u003e , one of the most recognizable signatures of Heerlen productions from the early 60s, known for its stability, build quality and high-level sound reproduction. \u003cbr data-start=\"480\" data-end=\"483\"\u003eThe set was selected in our laboratory as a \u003cstrong data-start=\"538\" data-end=\"554\"\u003eMatched Quad\u003c\/strong\u003e , with coherent electrical behavior and uniform timbre across all specimens. Bench testing confirmed \u003cstrong data-start=\"689\" data-end=\"697\"\u003e100%\u003c\/strong\u003e performance, with solid output, excellent linearity, and perfect operational stability.\u003c\/p\u003e\n\u003cp data-start=\"771\" data-end=\"1088\"\u003e\u003cstrong data-start=\"773\" data-end=\"799\"\u003eSound Characteristics\u003c\/strong\u003e\u003cbr data-start=\"799\" data-end=\"802\"\u003eThe 1963 Philips Heerlen 7189s are renowned for their combination of power, musicality and refinement.\u003cbr data-start=\"911\" data-end=\"914\"\u003eThe presentation is bright, defined and rich in micro-detail, with a tonal balance that places them among the best European interpretations of the EL84\/7189 family.\u003c\/p\u003e\n\u003cp data-start=\"1090\" data-end=\"1235\"\u003e\u003cstrong data-start=\"1090\" data-end=\"1099\"\u003eBass\u003c\/strong\u003e\u003cbr data-start=\"1099\" data-end=\"1102\"\u003eTight, fast, and compact. The low end is precise and controlled, without any bloat, with a powerful yet balanced response.\u003c\/p\u003e\n\u003cp data-start=\"1237\" data-end=\"1436\"\u003e\u003cstrong data-start=\"1237\" data-end=\"1245\"\u003eMedium\u003c\/strong\u003e \u003cbr data-start=\"1245\" data-end=\"1248\"\u003eThe strong point of Heerlen's production. \u003cstrong data-start=\"1297\" data-end=\"1341\"\u003eAiry, transparent mids, rich in harmonics\u003c\/strong\u003e , with realistic and natural voices. Excellent performance on acoustic instruments, jazz, and vocal music.\u003c\/p\u003e\n\u003cp data-start=\"1438\" data-end=\"1585\"\u003e\u003cstrong data-start=\"1438\" data-end=\"1446\"\u003eHigh\u003c\/strong\u003e\u003cbr data-start=\"1446\" data-end=\"1449\"\u003eBright, silky, and well-extended. The highs are defined and fluid, without harshness, with a finesse typical of vintage Philips EL84s.\u003c\/p\u003e\n\u003cp data-start=\"1587\" data-end=\"1790\"\u003e\u003cstrong data-start=\"1587\" data-end=\"1599\"\u003eDynamics\u003c\/strong\u003e\u003cbr data-start=\"1599\" data-end=\"1602\"\u003eLively, responsive, with excellent control at high volume.\u003cbr data-start=\"1660\" data-end=\"1663\"\u003eThe response is clean, stable, with great ability to follow transients and an energetic output without unwanted compression.\u003c\/p\u003e\n\u003cp data-start=\"1792\" data-end=\"1962\"\u003e\u003cstrong data-start=\"1792\" data-end=\"1806\"\u003eSoundstage\u003c\/strong\u003e\u003cbr data-start=\"1806\" data-end=\"1809\"\u003eWide, three-dimensional soundstage, with clear separation of musical lines. Excellent focus and depth, with a solid, well-layered image.\u003c\/p\u003e\n\u003cp data-start=\"1964\" data-end=\"2036\"\u003e🎧 \u003cstrong data-start=\"1967\" data-end=\"2004\"\u003eUse in Hi-Fi Stereo Amplifiers\u003c\/strong\u003e\u003cbr data-start=\"2004\" data-end=\"2007\"\u003ePerfect for amplifiers:\u003c\/p\u003e\n\u003cul\u003e\n\u003cli data-start=\"2039\" data-end=\"2077\"\u003eSherwood, Fisher and Scott of the time,\u003c\/li\u003e\n\u003cli data-start=\"2080\" data-end=\"2149\"\u003eEuropean amplifiers requiring 7189 for higher voltages,\u003c\/li\u003e\n\u003cli data-start=\"2152\" data-end=\"2213\"\u003esystems where clarity, naturalness and dynamics are desired.\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp data-start=\"2215\" data-end=\"2241\"\u003eThe quartet guarantees:\u003c\/p\u003e\n\u003cul\u003e\n\u003cli data-start=\"2244\" data-end=\"2264\"\u003euniform timbre,\u003c\/li\u003e\n\u003cli data-start=\"2267\" data-end=\"2296\"\u003eremarkable thermal stability,\u003c\/li\u003e\n\u003cli data-start=\"2299\" data-end=\"2337\"\u003ehigher headroom than common EL84s.\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp data-start=\"2339\" data-end=\"2411\"\u003eIdeal for jazz, vocal, classical, fusion and high definition listening.\u003c\/p\u003e\n\u003cp data-start=\"2413\" data-end=\"2539\"\u003e🎸 \u003cstrong data-start=\"2416\" data-end=\"2449\"\u003eUse in Music Amplifiers\u003c\/strong\u003e\u003cbr data-start=\"2449\" data-end=\"2452\"\u003eIn music, the 7189 is highly regarded in vintage high-voltage amps such as:\u003c\/p\u003e\n\u003cul\u003e\n\u003cli data-start=\"2542\" data-end=\"2561\"\u003eGibson GA-series,\u003c\/li\u003e\n\u003cli data-start=\"2564\" data-end=\"2613\"\u003eAmerican amplifiers with hot cathode bias,\u003c\/li\u003e\n\u003cli data-start=\"2616\" data-end=\"2691\"\u003eboutique projects requiring more robustness than standard EL84s.\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp data-start=\"2693\" data-end=\"2703\"\u003eThey offer:\u003c\/p\u003e\n\u003cul\u003e\n\u003cli data-start=\"2706\" data-end=\"2743\"\u003eprogressive and musical distortion,\u003c\/li\u003e\n\u003cli data-start=\"2746\" data-end=\"2781\"\u003egreat control over harmonics,\u003c\/li\u003e\n\u003cli data-start=\"2784\" data-end=\"2814\"\u003ewider and cleaner headroom.\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp data-start=\"2816\" data-end=\"2906\"\u003e🎯 \u003cstrong data-start=\"2819\" data-end=\"2851\"\u003eNote for audiophiles and technicians\u003c\/strong\u003e\u003cbr data-start=\"2851\" data-end=\"2854\"\u003eThis \u003cstrong data-start=\"2861\" data-end=\"2894\"\u003eMatched Quad Heerlen 1963 rX4\u003c\/strong\u003e features:\u003c\/p\u003e\n\u003cul\u003e\n\u003cli data-start=\"2909\" data-end=\"2957\"\u003ecareful selection for uniform behavior,\u003c\/li\u003e\n\u003cli data-start=\"2960\" data-end=\"2979\"\u003e\u003cstrong data-start=\"2968\" data-end=\"2976\"\u003e100%\u003c\/strong\u003e test,\u003c\/li\u003e\n\u003cli data-start=\"2982\" data-end=\"3019\"\u003eoperational stability and silence,\u003c\/li\u003e\n\u003cli data-start=\"3022\" data-end=\"3068\"\u003ehigh-end historic Philips building,\u003c\/li\u003e\n\u003cli data-start=\"3071\" data-end=\"3170\"\u003ePerfect compatibility with vintage devices that require real 7189s, not modern equivalents.\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp data-start=\"3172\" data-end=\"3361\"\u003eAn ideal set for restoration, upgrade or use in high precision hi-fi amplifiers.\u003c\/p\u003e\n\u003chr\u003e\n\u003ch3\u003e\u003cstrong\u003eTest Results:\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cp\u003eValve tested on \u003cstrong\u003eAMPLITREX AT-1000\u003c\/strong\u003e Tube Tester:\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003e\u003cstrong\u003eTest Conditions:\u003c\/strong\u003e \u003cspan\u003e\u003cmeta charset=\"utf-8\"\u003eVa = 250V, Vg2 = 250V, Vg = -7.3V\u003c\/span\u003e\u003c\/li\u003e\n\u003cli\u003e\u003cstrong\u003eAverage 100%:\u003c\/strong\u003e \u003cspan\u003e\u003cmeta charset=\"utf-8\"\u003eGm = 11.3 ; Ia = 48 mA\u003c\/span\u003e\u003c\/li\u003e\n\u003cli\u003e\u003cstrong\u003eTest Result:\u003c\/strong\u003e VERY STRONG\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp\u003e\u003cstrong\u003eValve 1:\u003c\/strong\u003e\u003cmeta charset=\"utf-8\"\u003e \u003cspan\u003eGm = 11.2 ; Ia = 48.4 mA\u003c\/span\u003e\u003cstrong\u003e\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cspan\u003e\u003cmeta charset=\"utf-8\"\u003e \u003cstrong\u003eValve 2:\u003c\/strong\u003e\u003cmeta charset=\"utf-8\"\u003e Gm = 11.0 ; Ia = 48.0 mA\u003c\/span\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cspan\u003e\u003cmeta charset=\"utf-8\"\u003e \u003cstrong\u003eValve 3:\u003c\/strong\u003e\u003cmeta charset=\"utf-8\"\u003e Gm = 11.0 ; Ia = 48.0 mA\u003c\/span\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cspan\u003e\u003cmeta charset=\"utf-8\"\u003e \u003cstrong\u003eValve 4:\u003c\/strong\u003e\u003cmeta charset=\"utf-8\"\u003e Gm = 11.4 ; Ia = 49.4 mA\u003c\/span\u003e\u003c\/p\u003e\n\u003cdiv\u003e\u003cstrong\u003eAdditional Tests Performed:\u003c\/strong\u003e\u003c\/div\u003e\n\u003cul\u003e\n\u003cli\u003e\u003cspan\u003e\u003cstrong\u003eMicrophonics:\u003c\/strong\u003e Low. 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 condition:\u003c\/strong\u003e Very good – Clearly legible writing with minor signs of wear, no obvious defects. See photos for details.\u003cstrong\u003e\u003cbr\u003e\u003c\/strong\u003e\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp\u003e\u003cstrong\u003eManufacturing Code:\u003c\/strong\u003e\u003cstrong\u003e\u003c\/strong\u003e\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003erx4 Δ3A3 →\u003cmeta charset=\"utf-8\"\u003e rxx indicates a 7189 with the sequential progression of x, where the increment of x indicates the production changes - \u003cmeta charset=\"utf-8\"\u003eΔ3A3 Δ → Heerlen (Netherlands), 3 (out of four digits) → 1963 - A → January - 3 → 3rd week of the month\u003c\/li\u003e\n\u003cli\u003e\u003cmeta charset=\"utf-8\"\u003e rx4 Δ3A2 →\u003cmeta charset=\"utf-8\"\u003e rxx indicates a 7189 with the sequential progression of x, where the increment of x indicates the production changes -\u003cmeta charset=\"utf-8\"\u003e Δ3A3 Δ → Heerlen (Netherlands), 3 (out of four digits) → 1963 - A → January - 2 → 2nd week of the month\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp\u003e\u003cmeta charset=\"utf-8\"\u003e\u003ca rel=\"noopener\" title=\"Why our tubes are different – the VTT protocol that improves sound, reliability and durability\" href=\"https:\/\/vacuumtubestreasures.com\/blogs\/notizie\/perche-le-nostre-valvole-sono-diverse\" target=\"_blank\"\u003e\u003cstrong\u003eFind out why our valves are different →\u003c\/strong\u003e\u003c\/a\u003e\u003c\/p\u003e","brand":"PHILIPS","offers":[{"title":"Default Title","offer_id":56200573747548,"sku":"03309","price":289.0,"currency_code":"EUR","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0616\/3775\/5127\/files\/1_66567479-58c7-43ce-8537-6e28121c233e.jpg?v=1765391469","url":"https:\/\/vacuumtubestreasures.com\/en-de\/products\/7189-sherwood-by-philips-heerlen-1963-gray-plates-%ce%b4x4-matched-quad-tested-100","provider":"Vacuum Tubes Treasures","version":"1.0","type":"link"}