12AU7A / ECC82 NOS RCA Matched Pair Tubes - Long Gray Plates Halo Getter USA

12AU7A / ECC82 NOS RCA Matched Pair Long Gray Plates Halo Getter Made in USA AMPLITREX Tested – VERY STRONG – Low Noise & Microphonics – Vintage American RCA Production Description: This matched pair of 12AU7A / ECC82 RCA NOS, Made in USA production, represents a particularly interesting selection for enthusiasts of the best vintage American tubes. Although branded RCA, the internal construction is clearly traceable to SYLVANIA USA production, recognizable by the typical structure with Long Gray Plates and Halo Getter, a configuration much appreciated for reliability, quiet operation, and balanced musicality. The tubes are in NOS (New Old Stock) condition and have been carefully selected and matched in our laboratory using an AMPLITREX AT-1000 Tube Tester, both testing VERY STRONG, with excellent electrical consistency and good balance between sections. The Low Noise & Microphonics selection makes them particularly interesting for quality hi-fi applications, including preamplifiers, line stages, and sensitive circuits. Aesthetically, the pair is in very good condition, with legible lettering and normal signs of age consistent with long-term storage. See photos for details. Sonic Characteristics The best Sylvania Long Gray Plates productions are appreciated for their tonal balance, natural midrange, and ability to deliver an engaging yet controlled musical reproduction. Bass The low end is well-articulated and controlled, with a pleasant sense of solidity and presence without excess. Midrange The midrange is one of the strengths of this production. Vocals are natural, well-focused, and rich in harmonic nuances, while acoustic instruments maintain remarkable timbral credibility. Treble The highs are open, clean, and well-extended, with a refined presentation that avoids any sense of aggressiveness. Dynamics Dynamic response is prompt and natural, with a good ability to follow musical variations and preserve the sense of rhythm. Soundstage The soundstage is wide and stable, with correct instrument placement and a pleasant sense of depth. 🎧 Use in Hi-Fi Amplifiers This pair is particularly suitable for: Tube preamplifiers Line stages Driver stages Integrated amplifiers DACs and tube buffers Restoration of vintage hi-fi electronics The Low Noise & Microphonics selection also makes them suitable for the most sensitive positions in the circuit. 🎸 Use in Musical Applications In amplifiers for musical instruments and compatible professional equipment, these 12AU7A can offer: Excellent operational stability Natural harmonic response Low noise Excellent signal intelligibility Features that make them interesting for both studio and live applications. 🎯 Note for Audiophiles and Technicians This pair combines several elements particularly appreciated by enthusiasts: Golden age American production RCA brand Sylvania USA construction Long Gray Plates Halo Getter Matched Pair Low Noise & Microphonics VERY STRONG performance A high-quality selection that offers the charm of the best vintage American production, with solid performance and great versatility of use. Test Results: Tube 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 Tube #1: Section 1: Gm = 2100 ; Ia = 9.0 mA Section 2: Gm = 2000 ; Ia = 9.6 mA Tube #5: Section 1: Gm = 2100 ; Ia = 9.0 mA Section 2: Gm = 2100 ; Ia = 8.8 mA Additional Tests Performed: Microphonics: Low. Tested and suitable for hi-fi use, including phono stages and guitar amplifiers. Also suitable for V1. Balance: The sections are consistent and well-aligned, making the tube suitable for use as a phase inverter in hi-fi and instrumental applications. Emission Quality: Excellent – Very strong and stable emission, without fluctuations. Shorts and GAS: Absent. Conditions: Condition: NOS - New Old Stock - Tested and working - Supplied in our custom box for optimal protection. Functionality: Perfectly operational. Aesthetic Condition: Very Good – Legible markings with slight signs of age. See photos for details. Manufacturing Code: undecipherable, identifiable by construction characteristics. 1960s Discover why our tubes are different →