RCA 6SN7GT

*BOGEYS*

GRAY SMOKE

RADIOTRON LOGO

*WEAPONS GRADE*

BOTTOM D GETTER

WINGED MICA TOP

BLACK LADDERS

PERFECT MATCHED QUAD

EXTREMELY RARE - NIB
(Original Factory Boxes)

EXCLUSIVE HIGH FIDELTY TUBE

🔥 RCA 6SN7GT / VT-231 – GRAY GLASS WWII ERA – RCA VICTOR “HIS MASTER’S VOICE” 🔥

  • ✔️ RCA Radiotron / RCA Victor (His Master’s Voice)

  • ✔️ Harrison, NJ build – flagship wartime facility

  • ✔️ Gray glass = rich, dense, warm tonal signature

  • ✔️ WWII production:

    • 📆 113 (April 1951)

  • ✔️ True VT-231 lineage – military-grade construction

  • ✔️ Thick mica / heavy plates / bottom getter

  • ✔️ Made in U.S.A. – peak industrial era

⚡ AUDIO PERFORMANCE

  • Deep, authoritative bass

  • Lush, forward mids

  • Smooth, extended highs

  • Wide soundstage, strong layering

  • Low noise, powerful emission

💎 WHY THESE

  • ✔️ Early RCA = tone + authority

  • ✔️ Scarce gray glass wartime pair

  • ✔️ True “bad boy” performers

  • ✔️ Audiophile + collector grade

📦 INCLUDED

  • Vintage RCA Radiotron boxes

  • Secure, professional packaging

🔥 FINAL TAKE

  • Harrison-built WWII muscle

  • Rugged, stable, and musical

  • Real-deal VT-231 bloodline

👉 Built for war… perfected for audio.


***Please read the entire listing thoroughly and ask any questions prior to purchase***

★★★ Amazing Historic Military Tubes ★★★

U.S. ARMY  U.S. NAVY  JAN  Military Specification Tubes

Production Year: Harrison, NJ - April 1951

Production Year: 1951

Matched Codes: 113

 Platinum Label

Tall Black Base

Set of Four (4) Tubes

***The Tubes Pictured are the Tubes Offered***

Made In the U.S.A.

★★★ These Tubes are Very Rare in Brand New Condition ★★★

BEST TUBES ON THE MARKET...  NO LEAKS...  NO SHORTS...


★★★ HICKOK TESTED ★★★

Tested on Hickok 750 for Emission, Mutual Conductance

Where 50 (μ) is Good these tubes peg at 79/80 for Emission

Where 2,600 (ma/V) is Good these tubes peg at 3,200 for Mutual Conductance

Tube 1. Plate 1. - 78 (μ) - 3,200 (ma/V)  at Idle - NOS

             Plate 2. - 75 (μ) - 3,100 (ma/V)  at Idle - NOS

Tube 2. Plate 1. - 78 (μ) - 3,200 (ma/V)  at Idle - NOS

              Plate 2. - 76 (μ) - 3,100 (ma/V)  at Idle - NOS

Tube 3. Plate 1. - 75 (μ) - 3,100 (ma/V)  at Idle - NOS

             Plate 2. - 78 (μ) - 3,200 (ma/V)  at Idle - NOS

Tube 4. Plate 1. - 76 (μ) - 3,100 (ma/V)  at Idle - NOS

              Plate 2. - 78 (μ) - 3,200 (ma/V)  at Idle - NOS

    Typical NOS (New) Tube Ratings are anything above 2600 (ma/V) for Mutual Conductance and 70 (μ) for Emission

***All Sets within a 2% to 5% Range***

Perfectly Balanced - Rare and Exceptional

Full Tonal Range - Powerful Emission


***We are Top Rated for a Very Good Reason. Buy with Complete Confidence***


*Test Ratings are Specific to My Fully Calibrated Test Equipment! The tubes are put through a Life Test and each plate is warmed and measured for mutual conductance, emission, leaks, and shorts... Each tube is thoroughly inspected, they are described accurately and listed based on fair value!

My Return Policy: 30 Days - Seller pays return shipping! All tubes are Guaranteed to be as described... Tube rolling will not be tolerated! Any and all returns must be in identical condition as when they were received... Test Driving Vintage NOS Tubes is completely unacceptable and highly unethical... Buyer will be charged for mishandled and damaged returns! 

All tubes manufactured emit some type of sound or hum... Microphonics are typically caused by a weak or broken internal weld and is an indication of a failing tube! Noisy tubes would always be auctioned or tossed... I mark every tube in order to avoid tube rolling! ***Variations in Line Output and Test Equipment excludes any claims regarding matching test results on any equipment other than mine... ***Test results from different Test Equipment IS NOT Guaranteed...


A Hickok 750 tube tester measures mutual conductance in micromhos (µmhos), not emission in milliamps (mA) or microamps (µA). Confusion likely arises because micromhos are based on a ratio of a change in plate current (measured in µA) to a change in grid voltage. 
Here is a breakdown of what the Hickok 750 measures and why it's not only an emission tester:
  • Mutual Conductance: The 750 is a dynamic mutual conductance tester. This is a more sophisticated test than a basic emission only test, which only checks the cathode's ability to emit electrons (super heated).
  • Micromho units: Mutual conductance is measured in micromhos, which translates to a specific change in the plate current per a change in the control grid voltage. The unit ma/V is the same as 1000 micromhos.
  • Superior test: A mutual conductance test is performed under simulated operating conditions and is considered more reliable for evaluating a tube's actual performance. This is why the Hickok 750 can identify weak tubes that might pass a simple emission only test.
  • Emission vs. Mutual Conductance: In contrast, a simple emission tester (like a Heathkit and many others) treats a tube like a simple diode, measuring only the cathode's emission strength. While useful for finding dead or very weak tubes, this method is not as thorough and test results are very unreliable.
A Hickok 750 tests for mutual conductance in micromhos (μmhos), which is sometimes abbreviated as μmos. The unit is a measure of a vacuum tube's transconductance (g{m}). Here's a breakdown: Micromhos (μmhos): This is the unit used to measure mutual conductance. A mho is an older term for the unit of electrical conductance, now called a siemens (S).Transconductance (g{m}): This is the technical term for mutual conductance. It is the ratio of the change in plate current (measured in microamps or milliamps) to a change in grid voltage (measured in volts).μmos: The term "umhos" or "umos" is sometimes used colloquially as an abbreviation for micromhos. Although the Hickok 750 measures the effect of microamps and volts to determine the final reading, the scale on the meter is calibrated to show the overall mutual conductance in micromhos.

International Buyers Welcome! I use eBay Global exclusively, unless otherwise stated... I am unable to change declared value on customs forms, and International Buyers are responsible for all taxes, customs and additional fees!  Each tube is fully insured, boxed and shipped safely!

 ★ Expedited Shipping ★

★ Shipping times may vary based on region ★

★ *Honesty, *Reliability and *Integrity are *Everything ★