6SN7 GTB Baldwin by SYLVANIA Matched Pair Black Plates Tubes Same Codes Made in USA '61

6SN7GTB Baldwin by SYLVANIA – Matched Pair – Same Data Codes – Made in USA 1961 AMPLITREX Tested – VERY STRONG – Low Noise & Microphonics – Vintage American Sylvania Production Matched pair of 6SN7GTB Baldwin by Sylvania, Made in USA 1961 production, selected for compatible hi-fi and musical applications requiring stability, channel consistency, and low noise. The tubes come from the same batch and have same data codes, an important detail for manufacturing and aesthetic uniformity. The construction is typical of Sylvania at the time, with black plates, upper halo getter, top getter flashing, black base, and a still clearly legible green Baldwin logo. The overall aesthetic conditions are excellent, with minimal signs compatible with age and vintage use. See photos for details. The pair has been tested on an Amplitrex AT-1000 Tube Tester with a VERY STRONG result and has been selected as Low Noise & Microphonics. The actual matching between the two tubes makes them a solid choice for systems where balance, quietness, and operational reliability are important elements. Sonically, it offers a full, stable, and musically balanced sound, with controlled bass, natural mids, clean highs, and an organized soundstage. The character is typical of vintage American Sylvania production: solid, fluid, and well-defined. Suitable for preamplifiers, driver stages, phase splitters, and circuits compatible with 6SN7 / 6SN7GTB. A truly selected, tested, and matched vintage American pair from Vacuum Tubes Treasures, ideal for those seeking reliable performance, low noise, and authentic Sylvania sound character. Test Results: Tubes tested on Amplitrex AT-1000 Tube tester: Test Conditions: Va = 250V, Vg = -8V Average 100% Gm = 2600 ; Ia = 9.0 mA Tube #3: Section 1: Gm = 2500 ; Ia = 8.0 mA Section 2: Gm = 2600 ; Ia = 8.6 mA Tube #13: Section 1: Gm = 2600 ; Ia = 7.6 mA Section 2: Gm = 2700 ; Ia = 9.2 mA Additional Tests Performed: Microphonics: Low. Tested and suitable for hi-fi use, even in phono stages and guitar amplifiers. Also suitable for V1. Emission Quality: Excellent – Very strong and stable emission, without fluctuations. Shorts and GAS: Absent. Condition: Condition: Vintage Tubes - Tested and fully functional. Supplied in our custom box for optimal protection. Functionality: Perfectly operational. Cosmetic Condition: Excellent – Markings well preserved, minimal signs of age. See photos for details. Manufacturing Code: 312 113 - 312 → Sylvania Electric Products Inc., Emporium, Pa. - 113 → 1 ( three digits ) → 1961 - 13 → 13th week of the year Discover why our tubes are different →