5963 / ECC82 NOS GE AMPLITREX Tested Long Gray Plates Horse Shoe Getter USA

5963 / 12AU7 / ECC82 NOS Stromberg Carlson by GE Long Gray Plates Horse Shoe Getter Made In USA '1959 AMPLITREX Tested – Low Noise & Microphonics – VERY STRONG – Vintage American GE Production Test Results: Tube tested on an AMPLITREX AT-1000 Tube Tester: Test Conditions: Va = 250V ; Vg = -8.5V 100% Average: Gm = 2200 ; Ia = 10.5 mA Test Result: VERY STRONG Tube #10: Section 1: Gm = 2900 ; Ia = 16.6 mA Section 2: Gm = 2780 ; Ia = 13.8 mA Additional tests performed: Burn-in / Stability Test: 48h – OK Microphonics: Low. Tested and compliant for use in hi-fi equipment and guitar amplifiers, even in the most sensitive audio stages. Noise: Low and well-controlled. Quiet operation in hi-fi settings and in music amplifiers in the intended positions. Balance: The sections are not perfectly aligned. The tube is suitable for hi-fi use in non-critical stages (input or driver) and in guitar amplifiers. Not recommended as a phase inverter or in applications requiring strict balance between sections. Emission Quality: Excellent – Very strong and stable emission, without fluctuations. Shorts and GAS: Absent. Description: Important 5963 NOS Stromberg-Carlson produced by General Electric, made in the United States in the 26th week of 1959. The construction with Long Gray Plates and the characteristic Horse Shoe Getter belongs to the American GE production of the late 50s and makes this tube particularly interesting for its build quality, performance, and historical charm. The code 59-26 188 confirms the manufacturing date and General Electric origin: 59-26 indicates the 26th week of 1959, while 188 is the EIA code assigned to General Electric. The Stromberg-Carlson branding identifies a production intended for the historic US electronics manufacturer; the EIA code and the internal structure clearly document its GE manufacture. Tested with an Amplitrex AT-1000, the tube recorded particularly high transconductance values: 2900 and 2780 µmhos, significantly higher than the nominal reference of 2200 µmhos. The anode currents of 16.6 and 13.8 mA also confirm an exceptionally vigorous emission, with both sections well above the nominal value of 10.5 mA. The two sections are very close in transconductance, while showing a more evident difference in anode current. The tube therefore offers a notable emission reserve, but should not be considered strictly balanced: it is particularly suitable for non-critical input stages, drivers, buffers, preamplifiers, and musical instrument amplifiers, while it is not recommended as a phase inverter or in applications requiring absolute symmetry between the sections. The 48-hour burn-in verified parameter stability without fluctuations. The tube exhibits low microphonics, low noise, absence of gas, and no shorts, characteristics that allow its use even in the most sensitive audio stages of compatible equipment. In terms of sound, this GE offers a clean, dynamic, and authoritative reproduction, with a natural and well-focused midrange, solid and controlled low frequencies, and defined highs without being harsh. The particularly high emission contributes to a responsive, energetic, and well-articulated sound, both in hi-fi and guitar amplifiers. A high-level proposal for those looking for an authentic 1959 American NOS 5963, with Long Gray Plates, Horse Shoe Getter, low microphonics, and electrical values well above nominal references: a Stromberg-Carlson produced by GE, carefully tested and ready for use. Condition: Condition: NOS - New Old Stock - Tested and working - Supplied in our custom box for optimal protection. Functionality: Perfectly operational. Cosmetic Condition: Excellent – Labels perfectly preserved, minimal signs of aging. See photos for details. Manufacturing Code: 59-26 188 → RMA/EIA Open Date Code → manufactured in the 26th week of 1959 - 188 → General Electric Company, Syracuse 1, N. Y. Discover why our tubes are different →