12AU7 / ECC82 Baldwin by RCA Matched Pair Clear Top Long Gray Plates Side D Getter Tubes Made in USA '50s
AMPLITREX Tested - Low Noise & Microphonics - VERY STRONG
Description:
This Matched Pair of 12AU7 / ECC82 Baldwin by RCA – Made in USA, circa 1959 represents one of the most interesting configurations of late 1950s American production.
Baldwin branded tubes were often produced by RCA for organ applications, following high quality standards and a selection focused on stability and consistency over time.
The construction configuration is particularly distinctive:
- Clear Top
- Long Gray Plates
- Side D Getter
The Clear Top design, typical of some RCA productions, promotes more efficient dissipation and a more open and linear response, contributing to clean and well-defined sound reproduction.
The pair comes from the same manufacturing lot and has undergone careful selection using Amplitrex AT-1000, resulting in a matched pair with extremely close values.
Both tubes are classified as VERY STRONG, with stable emission, low noise and microphonics, and have passed the burning test.
Timbral characteristics and sound description
This Baldwin by RCA pair offers a balanced, transparent, and highly consistent sound signature, with a presentation that prioritizes precision, naturalness, and control.
The Clear Top construction, combined with the long plates, delivers a clean and articulate sound, with a remarkable ability to maintain order and definition even in the most complex passages.
Bass
Fast and well-controlled, with excellent articulation.
Not intrusive, but always present and functional to the structure of the sound message.
Midrange
Linear and very legible.
Vocals emerge clearly, maintaining a natural rendition free from excessive coloration.
Treble
Open and clean, with good extension.
Never aggressive, they contribute to a general sense of air and transparency.
Dynamics
Responsive and precise, with very controlled transient management.
Excellent in both micro and macro dynamics.
Soundstage
Orderly and well-focused, with clear instrument separation and a stable scene.
🎧 Use in Hi-Fi Amplifiers
This pair is perfectly suited for high-level hi-fi applications:
- line preamplifiers
- phono stages
- drivers and buffers
The combination of professional matching, low noise, and operational stability makes it ideal for systems where consistency and quietness are essential.
🎸 Use in Musical Amplifiers
In musical applications, it offers:
- very controlled response
- excellent definition even in high-gain contexts
- predictable and consistent behavior between tubes
Particularly suitable for configurations where uniformity between multiple stages is required.
🎯 Note for audiophiles and technicians
- Baldwin by RCA – Made in USA (circa 1959)
- Clear Top – Long Gray Plates – Side D Getter
- Same manufacturing lot
- Matched pair
- VTT Classification: VERY STRONG
This pair represents a high-level solution, designed for those who want a truly consistent set, carefully selected and ready to be integrated into demanding systems.
This is not just a simple set of tubes, but a pair built and verified to work together, offering stability, precision, and reliable sound reproduction over time.
A selection that fully expresses the value of American RCA production, in the true Vacuum Tubes Treasures style.
Test Results:
Tube 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 #21:
Section 1: Gm = 2100 ; Ia = 9.7 mA
Section 2: Gm = 2000 ; Ia = 9.0 mA
Tube #24:
Section 1: Gm = 2000 ; Ia = 9.2 mA
Section 2: Gm = 2100 ; Ia = 9.8 mA
Additional Tests Performed:
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Microphonics: Low. Tested and suitable for hi-fi use, including phono stages and guitar amplifiers. Also suitable for V1.
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Balance: The sections are consistent and well-aligned, making the tube also suitable for use as a phase inverter in hi-fi and instrumental applications.
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Emission Quality: Excellent – Very strong and stable emission, without fluctuations.
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Shorts and GAS: Absent.
Conditions:
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Conditions: Vintage - Tested and functional - Supplied in our custom box for optimal protection.
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Functionality: Perfectly operational.
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Aesthetic conditions: Sufficient – Writings almost completely disappeared. See photos for details.
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Manufacturing Code: undecipherable, identifiable by construction characteristics. Late 1950s
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