12AU7A / ECC82 NOS Baldwin by SYLVANIA Long Gray Plates Halo Getter Matched Quad Tubes Made in USA '60s

12AU7 / ECC82 NOS Baldwin by SYLVANIA Matched Quad Long Gray Plates Halo Getter AMPLITREX Tested Made in USA ’60 AMPLITREX Matched Quad – Low Noise & Microphonics – Vintage American SYLVANIA Production Description This matched quartet of 12AU7 / ECC82 NOS Baldwin by Sylvania, Made in USA 1960 production, represents a high-level American selection, designed for hi-fi and musical applications where valve consistency, quietness, and operational stability are fundamental. Valves branded Baldwin were intended for musical and professional applications, particularly high-quality electronic organs, where reliable, stable, and quiet valves were required. Behind the Baldwin brand, in this case, we find the production of Sylvania Electric Products Inc., recognizable by its construction with Long Gray Plates and Halo Getter. The quartet comes from the same manufacturing code 312 052, traceable to the 52nd week of 1960. This element adds technical and collectible value, offering great production consistency among the four units. The valves are in NOS – New Old Stock condition, tested and selected using an AMPLITREX AT-1000 Tube Tester as a Matched Quad, with an overall VERY STRONG result, low microphonics, low noise, and passed a 48h Burning Test. The strength of this quartet is not only its very solid electrical state but, above all, the consistency of the values among the four valves, a particularly important feature in equipment that uses multiple 12AU7 / ECC82s in the same circuit. From an aesthetic point of view, the quartet is in excellent condition, with perfectly preserved labels, a clean internal structure, and minimal signs of aging. See photos for details. Tonal Characteristics and Sound Description Sylvania Long Gray Plates from the early 1960s are appreciated for a balanced, open, and natural sound reproduction, with a very recognizable American musicality. In this matched quad selection, the consistency among the four valves contributes to a stable, orderly, and very pleasant presentation, ideal for equipment that uses multiple 12AU7 / ECC82s in the same circuit. Bass The bass range is controlled, articulate, and well-supported. It provides a solid foundation without being intrusive, maintaining rhythm and clarity even in the most complex passages. Midrange The midrange is natural, clear, and musical. Vocals and acoustic instruments are well-focused, with a balanced and pleasant harmonic texture. Treble The treble range is open and clean, with good extension and a smooth, never aggressive, presentation. Detail remains well-integrated into the musical message. Dynamics Dynamics are prompt and consistent, with a stable and well-controlled response. The matching of the quartet helps maintain uniformity and tonal continuity between different circuit positions. Soundstage The soundstage appears wide, stable, and well-organized. The consistency of the quartet promotes proper instrument separation and a balanced presentation between channels. 🎧 Use in Hi-Fi Stereo Amplifiers This matched quartet is particularly suitable for: multi-stage tube preamplifiers line stages driver stages integrated amplifiers DACs and tube buffers hi-fi equipment using multiple 12AU7 / ECC82s restorations of vintage American electronics The Low Noise & Microphonics selection also makes it suitable for sensitive applications, including compatible phono stages and positions where quietness and consistency among valves are essential. 🎸 Use in Musical Instrument Amplifiers In musical instrument amplifiers and compatible professional equipment, these 12AU7 / ECC82 Baldwin by Sylvania can offer: excellent operational stability natural harmonic response contained noise low microphonics consistent behavior among the four valves good signal intelligibility These characteristics make the quartet interesting both in the studio and in live applications, always respecting the technical compatibility of the equipment. 🎯 Note for Audiophiles and Technicians This quartet combines elements particularly appreciated by enthusiasts: Sylvania Made in USA production Baldwin brand same manufacturing code 312 052 1960 production Long Gray Plates Halo Getter Matched Quad 48h Burning Test – OK Low Noise & Microphonics VERY STRONG performance on all valves A high-level selection for those who want a truly consistent, quiet, and stable quartet, capable of offering the charm of vintage American production with modern, accurate, and documented verification. Test Results Valves 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 #27 Section 1: Gm = 2100 ; Ia = 8.6 mA Section 2: Gm = 2200 ; Ia = 9.2 mA Valve #7 Section 1: Gm = 2200 ; Ia = 8.6 mA Section 2: Gm = 2200 ; Ia = 9.6 mA Valve #15 Section 1: Gm = 2100 ; Ia = 8.6 mA Section 2: Gm = 2300 ; Ia = 9.6 mA Valve #26 Section 1: Gm = 2200 ; Ia = 9.2 mA Section 2: Gm = 2200 ; Ia = 9.4 mA Additional Tests Performed Burning Test: 48h – OK Microphonics: Low. Tested and suitable for hi-fi use, even in phono stages and guitar amplifiers. Also suitable for V1. Balance: The sections are consistent and well-aligned, making the valves also suitable for use as phase inverters in hi-fi and instrumental applications. Emission Quality: Excellent – very strong and stable emission, without fluctuations. Shorts and GAS: Absent. Condition Condition: NOS – New Old Stock – tested and working. Supplied in our custom box for optimal protection. Functionality: Perfectly operational. Aesthetic Condition: Excellent – perfectly preserved labels, minimal signs of aging. See photos for details. Manufacturing Code: 312 052 → 312 indicates the manufacturer, which is Sylvania Electric Products Inc., Emporium, Pa. - 052 → 0 indicates 1960, 52 indicates the 52nd week of the year. Discover why our tubes are different →