5963 / ECC82 NOS GE AMPLITREX Tested Long Gray Plates Horseshoe Getter Balanced 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 – Balanced Sections – 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 #4:

• Section 1: Gm = 2600 ; Ia = 12.2 mA
• Section 2: Gm = 2100 ; Ia = 10.2 mA

• 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 musical amplifiers in the intended positions.
• Balance: Very good. The sections are consistent and well-aligned, making the tube also suitable for use as a phase inverter in hi-fi and instrumental applications.
• Emission Quality: Excellent – Very strong and stable emission, without fluctuations.
• Short Circuits 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 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 production intended for the historic US electronics manufacturer; the EIA code and internal structure clearly document the GE manufacture.

Tested with Amplitrex AT-1000, the tube recorded values of 2600 and 2100 µmhos, with anode currents of 12.2 and 10.2 mA. The overall average exceeds the nominal reference of 2200 µmhos and 10.5 mA, confirming vigorous emission and a tube still in excellent efficiency.

The 48-hour burn-in verified parameter stability without fluctuations. The tube features low microphonics, contained noise, absence of gas, and no short circuits. The two sections show good functional balance, even without absolute symmetry: it is therefore particularly indicated for hi-fi preamplifiers and drivers, headphone amplifiers, buffers, line stages, and musical instrument amplifiers. For phase inverter applications requiring extremely strict matching between sections, a tube with even closer values is preferable.

Sonically, this GE offers a clean, balanced, and authoritative reproduction, with natural midrange, solid and controlled low frequencies, and defined highs without being harsh. In hi-fi systems, it favors transparency and articulation; in guitar amplifiers, it ensures a responsive performance, good control, and a well-defined musical output.

A high-level proposal for those looking for an authentic 1959 American NOS 5963, with Long Gray Plates, Horse Shoe Getter, low microphonics, and overall emission exceeding nominal values: a Stromberg-Carlson produced by GE, carefully tested and ready to 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 well preserved, minimal signs of aging. See photos for details.
  
• Manufacturing Code: 59-26 188 → RMA/EIA Open Date Code → manufactured the 26th week of 1959 - 188 → General Electric Company, Syracuse 1, N. Y.

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