12AX7 / ECC83 NOS Baldwin by SYLVANIA - Matched Pair - Long Gray Plates Halo Getter USA 1961

12AX7 / ECC83 NOS Baldwin by SYLVANIA Gray Plates Halo Getter Matched Pair Made in USA 1961

Matched Pair – AMPLITREX Tested – Low Noise & Microphonics – Vintage American Sylvania Production

General Description

This matched pair of 12AX7 / ECC83 Baldwin by Sylvania, produced in the United States in 1961, represents one of the most appreciated American interpretations of the famous ECC83.

Tubes branded Baldwin were intended for high-end electronic organs of the time and were selected by manufacturers who required reliability, low noise, and long operational life. Behind the Baldwin brand, in this case, we find the renowned SYLVANIA Made in USA production, recognizable by its Gray Plates and Halo Getter construction, a configuration particularly appreciated by enthusiasts for its tonal balance and natural musicality.

Early 1960s Sylvania Gray Plates are known for their ability to combine detail, openness, and naturalness, offering an engaging yet never artificial reproduction.

This pair has been carefully selected and verified using AMPLITREX AT-1000, showing VERY STRONG performance on both tubes, with results exceeding nominal reference values.

From an aesthetic point of view, the tubes are in excellent condition, with a well-preserved internal structure and still legible markings.

Sonic Characteristics

Baldwin by Sylvania Gray Plates possess the typical high-quality American sound character, characterized by balance, musicality, and excellent intelligibility.

Bass

The bass is well-controlled and defined, with good presence and articulation. It provides solidity to the low end without making the musical message heavy.

Mids

The mid-range is probably the strong point of this production. Vocals appear natural, rich in harmonics, and well-focused in the soundstage.

Highs

The highs are open and detailed, but never aggressive. Environmental information and finer nuances are reproduced with naturalness and fluidity.

Dynamics

The dynamics are prompt and lively, with an engaging musical response that enhances both small ensembles and large orchestras.

Soundstage

The soundstage is wide and well-organized, with good depth and accurate instrument placement.

🎧 Use in Hi-Fi Amplifiers

This matched pair is particularly suitable for:

• Tube preamplifiers
• Integrated hi-fi amplifiers
• MM and MC phono stages
• Tube DACs
• Buffers and line stages
• Restorations of vintage American electronics

The Low Noise & Microphonics selection makes it suitable even for the most sensitive positions in the circuit.

🎸 Use in Musical Applications

Baldwin by Sylvania Gray Plates are also highly valued by musicians for their ability to offer:

• Excellent note definition
• Rich and musical mids
• Natural dynamic response
• Open but not aggressive sound

Particularly interesting for guitar amplifiers that require clarity, articulation, and vintage American musicality.

🎯 Note for Audiophiles and Collectors

Genuine Sylvania Gray Plates from the early 1960s, especially when available with the Baldwin brand and in such well-preserved condition, represent a very interesting choice for those who desire the classic vintage American sound.

The combination of:

• SYLVANIA Made in USA production
• Gray Plates
• Halo Getter
• Matched Pair
• Low Noise & Microphonics
• VERY STRONG performance on both tubes

makes this pair ideal for both quality hi-fi listening and for collectors and enthusiasts of American tube electronics.

Test Results:

Tube tested on AMPLITREX AT-1000 Tube Tester:

• Test Conditions: Va = 250V ; Vg = -2V
• Average 100%: Gm = 1600 ; Ia = 1.2 mA
• Test Result: VERY STRONG

Tube #9:

• Section 1: Gm = 2000 ; Ia = 1.4 mA
• Section 2: Gm = 1700 ; Ia = 1.3 mA

Tube #3:

• Section 1: Gm = 1900 ; Ia = 1.3 mA
• Section 2: Gm = 1900 ; Ia = 1.3 mA

• 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.

Condition:

• Condition: NOS - New Old Stock - Tested and working - Supplied in our custom box for optimal protection.
  
• Functionality: Perfectly operational.
  
• Cosmetic Condition: Excellent – Markings excellently preserved, minimal signs of age. See photos for details.
  
• Manufacturing Code: 312 139 → 312 indicates the manufacturer, Sylvania Electric Products Inc., Emporium, Pa. - 139 → 1 (three digits) → 1961 - 39 → 39th week of the year

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