12AU7A / ECC82 Lowray by RCA Clear Top 1959 - NOS Matched Pair - Long Gray Plates - Amplitrex Tested

12AU7A / ECC82 LOWRAY by RCA – Clear Top – 1959 – NOS Matched Pair – Long Gray Plates – Amplitrex Tested – Low Noise & Microphonics

Description:

This matched pair of 12AU7A / ECC82 LOWRAY by RCA , produced in the United States in 1959 , belongs to the famous Clear Top series by RCA, recognizable by the transparent top without upper flash getter.

The construction with long gray plates and a lateral getter is typical of RCA production in the late 1950s, known for its reliability, stability, and balanced tonal balance. The Lowray branding identifies a select supply for professional and instrumental applications.

The tubes are authentic NOS , selected as Matched Pair , Low Noise & Microphonics rated and tested in our laboratory on Amplitrex AT-1000 , ready for quality hi-fi and music applications.

Sound Characteristics

Bass: Precise, dry, and well-controlled. The low range is linear and defined, with good articulation and excellent rhythm control.

Mids: Clear and natural. Vocals are well-focused and believable, with a clean and coherent harmonic texture.

Highs: Open and airy. The top end is bright yet composed, with good extension and fine grain, typical of RCA Clear Tops.

Dynamics: Lively and stable. Excellent microdynamics and prompt transient response, with consistent and predictable behavior.

Soundstage: Wide and well-organized soundstage, with good separation of planes and a well-defined central image.

🎧 Use in Hi-Fi Amplifiers

Ideal for:

• line preamplifiers
• driver stages
• amplifiers that require clarity and precision

Particularly suitable for systems oriented towards transparency and control.

🎸 Use in Music Applications

Also very valid in:

• instrument amplifiers
• sensitive positions thanks to the Low Noise & Microphonics classification

They offer defined response, good articulation and stable behavior over time.

🎯 Note for audiophiles and technicians

• RCA Production – Made in USA – 1959
• Clear Top Version
• Lowray brand (select supply)
• Long Gray Plates
• NOS – New Old Stock
• Matched Pair selected
• Tested on Amplitrex AT-1000
• Low Noise & Microphonics

A classic pair of American RCA production from the late 1950s, appreciated for their clarity, balance and reliability, in the true Vacuum Tubes Treasures style.

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Test Results:

Valve tested on AMPLITREX AT-1000 Tube Tester:

• Test Conditions: Va = 250V, Vg = -8.5V
• Average 100%: Gm = 2200 ; Ia = 10.5 mA
• Test Result: VERY STRONG

Valve #1:

• Section 1: Gm = 2100 ; Ia = 10.0 mA
• Section 2: Gm = 2120 ; Ia = 10.2 mA

Valve #2:

• Section 1: Gm = 2000 ; Ia = 9.0 mA
• Section 2: Gm = 2200 ; Ia = 10.2 mA

Additional Tests Performed:

• Microphonics: Low. Tested and approved for use in hi-fi, including phono stages and guitar amplifiers. Also suitable for V1.
• Output Quality: Excellent – ​​Very strong and stable output, no fluctuations.
  
• Short circuits and GAS: Absent.

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Conditions:

• Condition: NOS - New Old Stock - Tested and in perfect working order. Comes in our custom box for optimal protection.
• Functionality: Fully functional.
• Aesthetic condition: Very good – Clearly legible writing with minor signs of wear, no obvious defects. See photos for details.

Manufacturing Code:

59-26 → RMA/EIA Open Date Code → manufactured week 26 of 1959 - 274 → Radio Corporation of America, Camden, NJ

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