5963 / ECC82 NOS GE AMPLITREX Matched Pair Long Gray Plate Horse Shoe Getter USA

5963 / 12AU7 / ECC82 NOS Stromberg Carlson by GE Long Gray Plates Horse Shoe Getter Made In USA '1959 AMPLITREX Matched – 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 Average 100%: Gm = 2200 ; Ia = 10.5 mA Test Result: VERY STRONG Tube #5: Section 1: Gm = 2600 ; Ia = 12.2 mA Section 2: Gm = 2100 ; Ia = 10.2 mA Tube #11: Section 1: Gm = 2600 ; Ia = 12.6 mA Section 2: Gm = 2500 ; Ia = 11.2 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 environments and in musical amplifiers in the intended positions. Balance: Good. The sections exhibit consistent balance, fully compatible for use in hi-fi and musical amplifiers, in all applications where absolute symmetry between sections is not required. Emission Quality: Excellent – Very strong and stable emission, without fluctuations. Short Circuits and GAS: Absent. Description: Important NOS pair of 5963 Stromberg-Carlson tubes produced by General Electric, made in the United States in the 26th week of 1959. The construction with Long Gray Plates and characteristic Horse Shoe Getter belongs to the American GE production of the late 50s and makes this pair particularly interesting for 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 run intended for the historic US electronics manufacturer; the EIA code and internal structure clearly document the GE manufacture. The two tubes form an Amplitrex Matched pair, with transconductance between 2100 and 2600 µmhos and plate currents between 10.2 and 12.6 mA. Overall, the recorded values confirm very strong and regular emission, with good electrical homogeneity between the two tubes and performance generally superior to nominal references. The 48-hour burn-in verified parameter stability without fluctuations. The pair exhibits low microphonics, contained noise, absence of gas, and no short circuits. The good balance of the sections makes them particularly suitable for hi-fi preamplifiers and drivers, headphone amplifiers, buffers, line stages, and musical instrument amplifiers, in applications where absolute symmetry between the two sections is not required. In terms of sound, these GEs offer clean, balanced, and authoritative reproduction, with a natural midrange, solid and controlled low frequencies, and defined highs without being harsh. In hi-fi systems, they promote transparency, image stability, and good articulation; in guitar amplifiers, they ensure a responsive, controlled, and well-defined musical output. A high-level proposal for those looking for an American NOS pair from the same batch, with Long Gray Plates, Horse Shoe Getter, low microphonics, vigorous emission, and good electrical selection: two authentic Stromberg-Carlson tubes produced by GE in 1959, individually tested and ready for use. Conditions: Condition: NOS - New Old Stock - Tested and functional - Supplied in our custom box for optimal protection. Functionality: Perfectly operational. Cosmetic condition: Excellent – Labels perfectly preserved, minimal signs of age. 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 →