12AU7 / ECC82 RCA Black Plates Square Getter Made in USA '56
AMPLITREX Tested – Low Noise & Microphonics – Balanced – STRONG - Vintage RCA Production
Test Results:
Tube tested on AMPLITREX AT-1000 Tube Tester:
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Test Conditions: Va = 250V ; Vg = -8.5V
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Average 100%: Gm = 2200 ; Ia = 10.5 mA
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Test Result: STRONG
Tube:
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Section 1: Gm = 1700 ; Ia = 8.6 mA
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Section 2: Gm = 1800 ; Ia = 8.4 mA
Additional Tests Performed:
- Burn-in / Stability Test: 48h – OK
- Microphonics: Low. Tested and suitable for use in hi-fi equipment and guitar amplifiers, even in the most sensitive audio stages.
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Noise: Low and well-controlled. Silent operation in hi-fi and musical amplifiers in the intended positions.
- Balance: Very good. The sections are consistent and well-aligned, making the tube also suitable for use as a phase inverter in hi-fi and instrumental applications.
- Emission Quality: Strong – Strong and regular emission, suitable for any application.
- Shorts and GAS: Absent.
Description:
Fine 12AU7 / ECC82 RCA, authentic American production Made in USA from 1956, characterized by the sought-after Black Plates with Square Getter construction. A particularly interesting configuration among the first RCA productions of the 12AU7 family, appreciated for its build quality, robustness, and typical American sonic character.
The manufacturing code 6-09 identifies a production from Radio Corporation of America, Camden, New Jersey, made in the 9th week of 1956. The Black Plates / Square Getter combination, typical of RCA productions from the 1950s, makes this example particularly interesting from both a technical and collector's perspective.
The tube has been carefully tested in our laboratory using an Amplitrex AT-1000 Tube Tester, achieving a STRONG rating. The two sections measured Gm 1700 / Ia 8.6 mA and Gm 1800 / Ia 8.4 mA respectively, showing consistent and very well-aligned values. The balance is very good, with strong, regular, and stable emission.
It also passed a 48-hour Burn-in / Stability Test and was selected for Low Noise & Microphonics, with low and well-controlled noise. It is therefore suitable for even the most sensitive audio stages, as well as for hi-fi preamplifiers, input stages, drivers, and guitar amplifiers. The good matching between the two triodes also makes it suitable for use as a phase inverter in compatible hi-fi and instrumental applications. No shorts, gas, or anomalies were detected.
Sonically, vintage RCA Black Plates 12AU7s are particularly appreciated for a full-bodied, natural, and musical presentation, with rich and well-defined mids, solid and controlled bass, and smooth but detailed high frequencies. A balanced and engaging performance, ideal for those seeking the classic character of historical American RCA productions from the 1950s.
Ideal for hi-fi preamplifiers, integrated amplifiers, line stages, DACs and tube buffers, input and driver stages, phase inverters, and guitar amplifiers compatible with 12AU7 / ECC82.
The tube is Vintage, carefully tested, and fully functional. The aesthetic conditions are good, with partially eroded but still legible screen printing and a well-preserved tube body. It comes in our custom box for optimal protection.
A valuable RCA 12AU7 / ECC82 Black Plates Square Getter from 1956, truly tested and selected by Vacuum Tubes Treasures, with STRONG emission, Low Noise & Microphonics, and very well-balanced sections: an authentic vintage RCA example particularly interesting for quality audio applications.
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: Good – Partially eroded but still legible lettering. Tube body in good condition. See photos for details.
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Manufacturing Code: 6-09 → RMA/EIA Open Date Code → manufactured the 9th week of 1956 → Radio Corporation of America, Camden, N. J.
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