6L6GB RCA Black Plates Double Bottom Getter – Matched Pair – AMPLITREX Tested – Made in USA – VERY STRONG Test
Description:
This matched pair of RCA 6L6GBs , made in the USA during the golden age of American manufacturing, represents one of the most solid and musically appreciated versions of the famous 6L6 family.
The black plate and double bottom getter construction is typical of high-quality RCA products, known for their excellent operational stability, mechanical robustness, and electrical coherence. Black plates, in particular, are highly sought after by enthusiasts for their ability to deliver a rich, natural, and authoritative sound.
The valves have been tested and selected in our laboratory on AMPLITREX AT-1000 , with VERY STRONG result, sign of very high emission and stable electrical behavior.
This Matched Pair configuration ensures good operational consistency between the two units, making the pair ideal for hi-fi amplifiers and quality music applications.
Sound Characteristics
Bass: Deep, solid, and well-controlled. The low end has weight and authority, while maintaining good articulation and rhythmic precision.
Mids: Rich and natural. Vocals emerge with great presence and realism, while acoustic instruments and piano display a full and believable harmonic texture.
Highs: Smooth and refined. The extension is broad but always controlled, with a fine grain that avoids any harshness even in the most revealing systems.
Dynamics: Smooth and progressive. Transient response is natural and musical, with excellent microdynamics and a very balanced overall performance.
Soundstage: Wide, well-layered soundstage, with good depth and natural separation of instruments.
🎧 Use in Push-Pull Stereo Hi-Fi Amplifiers
These RCA 6L6GB are particularly suitable for amplifiers designed for:
- 6L6GB
- 6L6GC
- 5881
- compatible variants of the 6L6 family
They are appreciated in hi-fi systems where one seeks:
- natural musicality
- timbre balance
- rich and realistic media
The Matched Pair configuration contributes to stable and consistent performance between channels.
🎸 Use in Music Applications
Also highly prized in vintage and boutique guitar amplifiers , where RCA black plates are known for:
- great harmonic richness
- full and musical mids
- progressive and natural dynamic response
Qualities that contribute to a warm, articulate and deeply musical sound.
🎯 Note for audiophiles and technicians
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RCA Production – Made in USA
- Black Plates
- Double Bottom Getter
- Matched Pair
- AMPLITREX AT-1000 Tested
- Test VERY STRONG
A pair representative of the great RCA tradition in the production of power tubes , capable of offering reliability, musicality and the authentic sonic character of the best American 6L6GBs .
Test Results:
Tested on AMPLITREX AT-1000 Tube tester:
Test Conditions: Va = 350; Vg2 = 250; Vg = -18V
Average 100% Gm = 5.2 ; Ia = 54.0 mA
TEST RESULT: VERY STRONG
Valve 1: Gm = 4.66 ; Ia = 45.6 mA
Valve 2: Gm = 4.78 ; Ia = 50.8 mA
Additional Tests Performed:
- Microphonics: Standard. Tested and approved for use in hi-fi and guitar amplifiers.
- Output Quality: Excellent – Very strong and stable output, no fluctuations.
- Short circuits and GAS: Absent.
Conditions:
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Condition: Vintage tubes - Tested and in perfect working order. Shipped in our custom box for optimal protection.
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Functionality: Fully functional.
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Aesthetic condition: Fair – Writing almost completely faded. See photos for details.
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Manufacturing Code: None. Unreadable, identifiable by construction features. Made by RCA USA, likely early 1950s.
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