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
Matched Quad of 12AU7 / ECC82 NOS Baldwin by Sylvania, Made in USA 1960 production, selected for compatible hi-fi and musical applications where consistency between tubes, low noise, and operational stability are important elements.
Baldwin-branded tubes were intended for musical and professional applications, particularly high-quality electronic organs. In this case, the production is traceable to Sylvania Electric Products Inc., with Long Gray Plates and Halo Getter construction.
The quad comes from the same manufacturing code 312 052, traceable to the 52nd week of 1960, a positive detail for production uniformity, aesthetic consistency, and collectible value.
The tubes are in NOS – New Old Stock condition, with clean internal structure, well-preserved lettering, and minimal signs of age. See photos for details.
Tested and selected using the Amplitrex AT-1000 Tube Tester as a Matched Quad, they achieved an overall VERY STRONG result, with Low Noise & Microphonics and Burning Test 48h passed. The consistency of values between the four tubes makes this quad particularly interesting for equipment that uses multiple 12AU7 / ECC82s in the same circuit.
Sonically, they offer a balanced, open, and natural reproduction, with controlled bass, clear and musical mids, clean highs, and a stable soundstage. The matching of the quad promotes tonal uniformity, consistency between circuit positions, and an orderly presentation.
Suitable for multi-stage tube preamplifiers, line stages, drivers, integrated amplifiers, DACs, tube buffers, vintage restorations, and circuits compatible with 12AU7 / ECC82. Also usable in compatible musical applications where low noise, stability, and natural harmonic response are required.
A truly selected, tested, and matched American NOS quad from Vacuum Tubes Treasures, ideal for those seeking vintage Sylvania production, electrical consistency, and reliable performance.
Test Results
Tubes 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 #27
Section 1: Gm = 2100 ; Ia = 8.6 mA
Section 2: Gm = 2200 ; Ia = 9.2 mA
Tube #7
Section 1: Gm = 2200 ; Ia = 8.6 mA
Section 2: Gm = 2200 ; Ia = 9.6 mA
Tube #15
Section 1: Gm = 2100 ; Ia = 8.6 mA
Section 2: Gm = 2300 ; Ia = 9.6 mA
Tube #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, including phono stages and guitar amplifiers. Also suitable for V1.
Balance: The sections are consistent and well-aligned, making the tubes 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.
Conditions
Conditions: NOS – New Old Stock – tested and functional. Supplied in our custom box for optimal protection.
Functionality: Fully operational.
Cosmetic condition: Excellent – lettering perfectly preserved, minimal signs of age. See photos for details.
Manufacturing Code: 312 052 → 312 indicates the manufacturer, namely Sylvania Electric Products Inc., Emporium, Pa. - 052 → 0 indicates 1960, 52 indicates the 52nd week of the year.
Discover why our tubes are different →