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 – 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 authentic vintage Sylvania sound character. The tubes come from the same lot and feature same data codes, an important detail for manufacturing and aesthetic uniformity. The construction is typical Sylvania of the era, with black plates, top halo getter, top getter flashing, black base, and a still-legible green Baldwin silkscreen. The overall cosmetic condition is 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 a Matched Pair. The actual matching between the two tubes makes it a solid choice for compatible circuits requiring balance, stability, and operational reliability. From a sonic perspective, it offers a full, stable, and musically balanced performance, 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 driver stages, phase splitters, buffers, and circuits compatible with 6SN7 / 6SN7GTB. A truly tested, selected, and matched vintage American pair from Vacuum Tubes Treasures, ideal for those seeking a solid, consistent, and vintage-sounding 6SN7GTB Sylvania Made in USA. 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 #6: Section 1: Gm = 2600 ; Ia = 8.6 mA Section 2: Gm = 2500 ; Ia = 9.2 mA Tube #1: Section 1: Gm = 2600 ; Ia = 9.4 mA Section 2: Gm = 2500 ; Ia = 8.4 mA Additional Tests Performed: Microphonics: Standard. Tested and suitable for use in hi-fi and guitar amplifiers. Recommended for use in V2, V3, V4, as a driver or in less critical stages. Not recommended in V1 or in very high gain positions particularly sensitive to microphonics. Emission Quality: Excellent – Very strong and stable emission, without fluctuations. Shorts and GAS: Absent. Conditions: Conditions: Vintage Tubes - Tested and perfectly 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 →