12AT7 ECC81 NOS Sylvania – Black Wing Plates Square Getter Pair Tubes USA 1949

12AT7 ( ECC81 ) SYLVANIA NOS Black Wing Plates Square Tilt Getter Tested Pair Tubes Made in USA '49

Description:

The 12AT7 SYLVANIA , in the black wing plates and square tilt getter configuration, represents one of the most interesting expressions of American production in the late 1940s. This NOS pair, electrically tested but not matched , offers a clear, lively and well-controlled timbre, with a sound setting that favors transparency, articulation and dynamic reactivity , while maintaining good musical coherence.

Bass : fast, dry and well defined. The bass is present without excess, with a tense and rhythmic response, ideal for systems that require articulation and control, without the need for additional euphony.

Mids : bright, direct and clean. Voices are well focused, with a clear and slightly analytical rendering, without ever becoming dry. Acoustic instruments emerge with energy and good separation.

Highs : airy and precise, with a controlled brilliance. The high range develops without harshness, always maintaining a transparent, refined character and well integrated with the rest of the spectrum.

Dynamics : very reactive and proportionate. The valve promptly follows the variations of the signal, returning microdetails and nuances without stiffening. The effect is that of a response that is always ready, but musical.

Soundstage : Focused, uncluttered and coherent. The stereo image develops clearly, with good lateral separation and a well-defined centre, offering a credible soundstage, although not as wide as that of more euphonic valves.

The pair of 12AT7 SYLVANIA black wing plates – USA 1949 , although not matched, presents itself as a quality technical and musical choice , suitable for those looking for a fast, open and coloration-free voice , both in hi-fi applications and in the professional field.

🎧 Use in Headphone Amplifiers and Driver Stages Hi-Fi

This tube is well suited to transparent, low distortion, high resolution systems , where faithful detail reproduction and a well-readable midrange are required. In headphone amplifiers such as Feliks Echo , Schiit Lyr , or in tube preamplifiers, the 12AT7 SYLVANIA allows for clear, controlled, and non-fatiguing reproduction, with a precise and articulated soundstage.

🎸 Use in Guitar and Bass Amplifiers

Also popular in guitar amplifiers , this vintage 12AT7 is often used as a driver stage or phase inverter in models such as the Fender Deluxe Reverb , Twin Reverb and in blackface-style boutique amplifiers. It offers high headroom, defined attack and progressive saturation , particularly useful for those looking for a clean, articulate and musical sound . Even in tube bass amps, it guarantees a controlled low end and a quick response under load.

🎯 Note for audiophiles :
A sober, transparent tube with a very natural dynamic behavior , ideal for those who want a neutral but engaging timbre restitution , without excesses or forced colorations. Also excellent for comparisons and system tests.

Test Results:

Valve tested on AMPLITREX AT-1000 Tube Tester:

• Test Conditions: Va = 250V, Vg = -2V
• Average 100%: Gm = 5.5 ; Ia = 10.0 mA
• Test Result: VERY STRONG

Valve 1:

• Section 1: Gm = 6.5 ; Ia = 14.9 mA
• Section 2: Gm = 6.4 ; Ia = 13.5 mA

Valve 2:

• Section 1: Gm = 5.5 ; Ia = 10.4 mA
• Section 2: Gm = 5.6 ; Ia = 11.8 mA

Additional Tests Performed:

• Microphonics: Low – Tested and rated for use in hi-fi systems and guitar amplifiers.
• Output Quality: Excellent – Very strong and stable output, no fluctuations.
  
• Short circuits and GAS: Absent.

Conditions:

• Condition: NOS - New Old Stock - Tested and fully functional. Supplied in our custom box for optimal protection.
• Functionality: Fully functional.
• Cosmetic Condition: See photos for details.
• Manufacturing Code: 913 - produced 13th week of 1949

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