This listing is for a ONE Strong tube with 5%-6% Balanced Plates,  

1969 '69-48' RCA 12BH7A Centered Gray Ribbed Plates

with thick top side 'O' Halo Getter Tube with two thoriated Black coated heat dissipation Cathode vents .

This tubes red ink is faded but visible is '69-48' '274' date code/manufacturers code

 and red inked  'for DeVry Tech by RCA' (see pics)

This tube ships in a new RCA box with a printed page of the test results and this description.

This and 3 other 1960's RCA 12BH7A's were pulled from surplus Electronic Lab equipment we purchased

which were branded for DeVry Tech by Heath/Hickok/Tektronix.

Condition: Lightly Used, and tested Strong above RCA factory 'Bogey' specs for Gm & mA.

Clean pins, Plug-in and Play condition.

Dan Nelson Calibrated( 07/24/2023)  TV7D/U Test Results, tested at 150VDC Plate supply Voltage. 

TESTED NO Shorts, No Leakage, No Gas, No Apparent Micro-Phonics detected

 TESTED Above average RCA Factory new  Levels for Gm & mA (see pic of RCA 12BH7-A data sheet)

notes - fyi,  Original Manufacturers such as RCA for Twin Triodes would pass final factory QA Testing if the plates

are matched at <=10% of tested value for Gm & mA for general public use (radio,TV & Hi-Fi). Some military contracts and 

Professional Lab Equipment manufacturers such as Tektronix stipulated a <=5% plate match.

Tube 1:  ( 6% Balanced Plates for Gm transconductance & 5% Anode Plate Current emissions)

   Side 1:  72.2 = 3,610 uMhos Transconductance (Gm)  at  17.3 mA (Ia =Anode Plate Current)

   Side 2:  77.0 = 3,850 uMhos Transconductance (Gm)  at  18.2 mA (Ia =Anode Plate Current)

TESTING:  TV7D/U Minimum Good  (60-65% Tube Life) is a meter reading of 30/30 = 1,500/1,500 uMhos Gm.

Average Industry NOS 'Bogey' Operating in CLASS A1 Amplifier when tested at 250VDC Plate Supply 

Voltage is a TV7 meter reading of reading 62/62 = 3,100 / 3,100 Gm at 11.5/11.5 mA plate current emissions. 

(See last pic for RCA Data Sheet dated 1955 to verify these 'Bogey' #'s for Gm & mA)

Physical Characteristics: (See all Pics)

- Glass Etched : "U.S.A." above "12BH7A" inside an Octangle Stop Sign with line edge breaks.

- Centered Long Ribbed Gray Plates

- 2 spiked mica wafer/spacers with thick metal support rods.

- Two thoriated black heat dissipation vents atop the topside spacer/wafer just below the Halo.

- Red ink is mostly fading but visible '69-48' "274" "for DeVry Tech by RCA"

This tube will ship in new RCA box with test result hand written on sides of the box.

You will receive a print out of this detailed description with test results in the box shipped.

Our test set: Dan Nelson restored, upgraded and calibrated (07/24/2023) TV7D/U with Digital Meter reading 

Transconductance in uMhos (Gm) and mA (Anode Plate Current).

WE PACK VERY WELL AND SHIP WORLDWIDE.

ALL 50 States +PO BOXES+APO/FPO's via USPS Advantage Small Parcel (USPS 1st Class)

INTERNATIONAL via eBay International Shipping, low cost economy Parcel, space available air-freight to over 100 countries. If your country is in the drop down list under the shipping Tab than WE SHIP!