12AX7 / ECC83 TUNG-SOL Long Gray Plates Halo Getter - Balanced - Low Noise & Mic Tube USA 1960s

12AX7 / ECC83 TUNG-SOL Long Gray Plates Halo Getter Tube USA 1960s

AMPLITREX Tested – Low Noise & Microphonics – Balanced – Vintage American TUNG-SOL Production

Test Results:

Tube tested on AMPLITREX AT-1000 Tube Tester:

• Test Conditions: Va = 250V ; Vg = -2V
• 100% Average: Gm = 1600 ; Ia = 1.2 mA
• Test Result: STRONG

Tube:

• Section 1: Gm = 1300 ; Ia = 0.8 mA
• Section 2: Gm = 1300 ; Ia = 0.8 mA

Description:

Selected vintage specimen of 12AX7 / ECC83 Tung-Sol, made in the United States and featuring the refined Long Gray Plates with Halo Getter construction, attributable to the historic American production of the 1960s. This configuration represents one of the expressions of the Tung-Sol thermionic tradition, particularly interesting for audiophiles and musicians looking for authentic vintage American tubes, built according to the quality standards of the original production.

The measurements performed with Amplitrex AT-1000 highlight an excellent electrical balance, with perfectly identical values in the two sections. The transconductance reaches 1300 µmhos for both triodes, corresponding to 81.25% of the nominal reference of 1600, while the anode currents are uniform at 0.8 mA, compared to the reference of 1.2 mA. Although the values are lower than the nominal references, the perfect correspondence of the measurements confirms a particularly accurate internal symmetry, an appreciable feature in applications requiring electrically balanced sections.

The tube passed 48 hours of burn-in and stability testing, maintaining a strong and even emission, without fluctuations, short circuits, or the presence of gas. A particularly significant element is represented by the extremely low noise and microphonics levels, verified during testing. This selection makes the specimen particularly interesting for the most sensitive audio stages, where silence and stability are fundamental requirements.

The 12AX7 / ECC83 Tung-Sol Long Gray Plates find application in hi-fi preamplifiers, compatible phono stages, and guitar amplifiers, including input stages and phase inverter circuits. The identity of the electrical characteristics of the two sections constitutes a favorable element in applications requiring a good internal balance. The American Tung-Sol production of this period is traditionally appreciated by audiophiles for a musical presentation generally described as dynamic, detailed, and harmonically rich, with a medium expressive range and good tonal articulation.

The value of this specimen lies in its authentic Tung-Sol Long Gray Plates construction, the excellent balance of the sections, and, above all, the ultra-low noise selection. The absence of decipherable manufacturing codes does not allow for precise dating, although the construction features are attributable to the American production of the 1960s. The partially faded screen printing and obvious signs of age testify to the vintage nature of the tube, while instrumental tests document its full current functionality. An authentic vintage American Tung-Sol, carefully tested and selected, for those seeking an original tube with documented electrical characteristics, verified stability, and extremely low microphonics.

Condition:

• Condition: Vintage Tubes - Tested and perfectly functional. Supplied in our custom box for optimal protection. 
  
• Functionality: Perfectly operational.
  
• Aesthetic condition: Adequate – Partially faded or barely legible markings, overall aesthetics with obvious signs of age. See photos for details.
  
• Manufacturing Code: Code not decipherable. Production attributable approximately to the 1960s based on construction features.

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