12AU7 ( ECC82 ) SYLVANIA NOS Short Gray Plates Square Getter Tested Tube Made in USA '47

12AU7 ( ECC82 ) SYLVANIA NOS Short Gray Plates Square Getter Tested Tube Made in USA '47

Note: Price refers to one selected valve

Description:

This 12AU7 / ECC82 SYLVANIA NOS , Made in USA 1947 , belongs to the very first historical productions of this tube, built in the immediate post-war period to extremely high construction standards. The configuration with short gray plates and square getter identifies a very early variant, rare today, appreciated for its mechanical solidity, operational stability and very refined sonic character.
The valve is tested and perfectly efficient, transmitting from the first notes the sensation of an authentic, selected component of great historical value.

Sound Characteristics

Bass: Clean, well-controlled, and natural. The low end is composed and coherent, with a tidy response that supports the music without being heavy.

Mids: The hallmark of this production. Rich, fluid, and very realistic, with present vocals and an elegant harmonic texture, typical of early Sylvania from the 1940s.

Highs: Sweet, silky, and perfectly integrated. The highs are refined and never aggressive, encouraging relaxed, long-lasting listening.

Dynamics: Balanced and fluid. The response is prompt but always controlled, with a natural microdynamic that restores vitality without forcing.

Soundstage: Stable, airy, and well-proportioned. The soundstage is believable, with natural instrument placement and consistent depth.

🎧 Use in Hi-Fi Amplifiers

Ideal for:

• high-end preamplifiers and line stages,
• drivers in single-ended and push-pull amplifications,
• hi-fi systems that prioritize naturalness, musicality and timbral coherence.

Particularly suitable for jazz, vocal, classical and acoustic music.

🎸 Use in Music Applications

Suitable for:

• instrument amplifiers in driver stages or vintage circuits,
• boutique projects that seek an authentic and refined sound character.

It offers a full, controlled and harmonically rich sound.

🎯 Note for audiophiles and technicians

This 12AU7 / ECC82 SYLVANIA NOS – Short Gray Plates – Square Getter (1947) represents:

• an extremely early and now rare American production ,
• Sylvania post-war build quality,
• stable and reliable electrical behavior,
• elegant, natural and historically correct timbre.

A valve designed for those who want not just a NOS 12AU7 , but an authentic original sound experience , capable of enhancing high-end hi-fi systems with timeless class and personality.

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 = 2050 ; Ia = 9.5 mA

Valve 2:

• Section 1: Gm = 2050 ; Ia = 9.5 mA
• Section 2: Gm = 2100 ; Ia = 10.0 mA

Valve 3:  SOLD

• Section 1: Gm = 2100 ; Ia = 9.5 mA
• Section 2: Gm = 2100 ; Ia = 9.5 mA

Valve 4:

• Section 1: Gm = 2000 ; Ia = 9.5 mA
• Section 2: Gm = 2050 ; Ia = 9.5 mA

Valve 5:     SOLD

• Section 1: Gm = 2100 ; Ia = 10.0 mA
• Section 2: Gm = 2150 ; Ia = 10.0 mA

Valve 6:     SOLD

• Section 1: Gm = 2150 ; Ia = 10.5 mA
• Section 2: Gm = 2100 ; Ia = 10.0 mA

• 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.

Conditions:

• Condition: NOS - New Old Stock - Tested and working - Supplied in our custom box for optimal protection.
  
• Functionality: Fully functional.
  
• Cosmetic condition: Excellent – Excellently preserved lettering, minimal signs of wear. See photos for details.
  
• Manufacturing Code: 502 752 → 502 (administrative origin) manufactured by Sylvania for American Radio Hardware Co., Inc., Mt. Vernon, NY - 752 → 2 (of three digits) → 1947 - 52 → 52nd week of the year

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