12AT7WA ( E81CC 6201 ) SYLVANIA NOS 3 Mica Gray Wing Plates Square Tilt Getter Tested Tube Made in USA '47
Description:
The 12AT7 WA (E81CC) SYLVANIA , produced in 1947 in the military version (WA), features a 3-mica configuration, grey wing-type plates and a square tilt getter , which testify to its origins among the first series of technical excellence in the post-war period. This valve is a rare example of balance between structural robustness and sonic refinement , with a tonal output that combines precision, transparency and dynamic control.
Bass : dry, well-defined, and fast. The low register is not pronounced but extremely controlled, ideal for applications requiring precise rhythm and the absence of swelling , while maintaining a firm and coherent harmonic foundation.
Mids : Tidy, transparent, and slightly refined. Vocals are well-centered, with a natural timbre and a discreet yet discernible presence. Acoustic instruments maintain clarity without ever being intrusive. The overall character is sober and balanced.
Highs : extended and refined, with an open yet controlled texture. The high range never pushes forward, but accompanies the listening experience with elegance and coherence , avoiding harshness or fatigue even on high-resolution systems.
Dynamics : fluid, smooth, and precise. The valve responds immediately but measuredly, without excess, allowing for clear reading of microdetails and a harmonious transition between different sound intensity levels.
Soundstage : coherent, stable, and well-focused. The stereo image develops naturally, maintaining good channel separation and credible instrument placement, with a transparent but never cold soundstage.
The 12AT7 WA SYLVANIA 3 mica from 1947 , in this NOS version tested , is a valve with a neutral, polite and professional character, ideal for those seeking cleanliness, readability and operational stability in the audio field, both in hi-fi systems and in technical and professional equipment.
🎧 Use in Headphone Amplifiers and Hi-Fi Driver Stages
Thanks to its tonal transparency and the absence of artificial enhancements , the 12AT7 WA SYLVANIA proves excellent in the best headphone amplifiers and tube preamplifiers. In circuits such as mu-follower , SRPP , or cathode follower , it delivers a clear, detailed and fatigue-free sonic presentation, enhancing reference headphones such as the Sennheiser HD650 , Focal Clear , Hifiman Ananda or ZMF Aeolus , in configurations that aim for neutral and natural reproduction .
🎸 Use in Guitar and Bass Amplifiers
The 12AT7 WA SYLVANIA also finds its place as a driver or inverter in tube guitar amplifiers , especially in blackface or vintage-inspired boutique Fender models that use this type of tube to optimize headroom and definition . It offers a clean, controlled sound with a ready attack and progressive saturation , ideal for musicians who want linear dynamic response and tonal fidelity . On bass amps or rack preamps, it allows for a tight and articulate output, with excellent detail in complex passages.
🎯 Note for audiophiles :
A sober, solid and coherent tube, perfect for those seeking technical rigor and controlled musical performance , without timbral imbalances or artificial euphony. A reliable foundation for neutral listening systems or for professional applications where transparency in the gain section is essential.
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:
- Section 1: Gm = 4.1 ; Ia = 9.6 mA
- Section 2: Gm = 5.9 ; Ia = 12.8 mA
Additional Tests Performed:
- Microphonics: Low Noise & Microphonics – Tested and compliant 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 in perfect working order. Comes in our custom box for optimal protection.
- Functionality: Fully functional.
- Cosmetic condition: Good – Lettering partially eroded, but still legible. Valve body in good condition. See photos for details.
- Manufacturing Code: 706 - produced 6th week of 1947
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