with MATCHED Plates,'Lightly Used' Dated ('5 23' ) 1955 JAN-CTL 5998 Tung-Sol Twin Triode Tube,
TV7D/U Tested for Transconductance(Gm) & mA Plate Current Emissions (read details of test results below)
Manufacturer : TUNG-SOL (Chatham a Division of Tung-Sol) Made in USA
Date of Production: 23rd week 1955
Condition: Lightly Used tested Gm&mA very good, Transconductance Gm=88%-90% of average Factory new.
mA=Plate Current emissions tested at 100%/100% average factory new.
Inked: White inked on Black Phenolic base "TUNG-SOL" "JAN-CTL-5998" "5 23" "Made in U.S.A."
Physical Characteristics ( TUNG-SOL JAN 5998 Twin/Double Triode):
- Excellent Glass and clear Lettering (see pics)
- Glass Envelope/Voltages : ST-16 shoulder shaped, Vf: 6.3V If: 2.4 Amperes
- Three Top Side Wings
- Thoriated Tungsten Anthracite BLACK 'Domino' Anode Plates
- Two top side Thoriated Black Cathode Heat Vents
- Triple(3x) Mica round spacers/wafers
- Thick metal support Rods
- Two top-side Large Horseshoe 'D' Getters
- 360 degree top of glass Silver Slashing
- Octal 8-pin base with locator
NOTE: No original box or spare box. We will special package
this tube very well with extra damping packing material and the box
will be very well packaged for safe shipping worldwide.
-Tube Type : JAN 5998 Tung-Sol (Chatham a Division of TUNG-SOL) identical to 421A_WE
Country: United States of America (USA) |
|
| | Tube Developer: Western Electric Company, Inc NY,NY. | | | Tube type: Double Triode Power-supply |
|
|
| Identical to | 5998 = 421A_WE |
| Base | Octal (Int.Octal, IO) K8A, USA 1935 |
| Filament | Vf 6.3 Volts / If 2.4 Ampere / Indirect / Specified voltage AC/DC |
| Description | Dual triode intended for use as series regulator in voltage stabilized power supply circuits. µ = 5.5 This (5998) is the RMA/EIA code for the WE 421A. |
Tested NO Shorts, No Gas, No Leakage, No Apparent Micro-phonics detected.
Note: All TV7 versions test tubes at a maximum of 150VDC Plate Supply Volts and
a maximum 135VDC Screen/Grid Volts and from 0V to -40VDC on the Control Grid "Bias" setting.
'Bogey value': Minimum good tube life at 60-65% = TV7 meter reading of 40 = 5,000 uMhos transconductance (Gm).
Average Factory new when tested at 150VDC Plate supply should be
equal or > a TV7 meter reading of 64 = 8,000 uMhos transconductance (Gm) with average Plate Current zero signal
when tested at 150VDC Plate volts with >= 50mA Plate current emissions (see Tung-Sol engineering data sheets and graphs).
Notes: We just completed testing quantity 19 of these tubes. Only 7 pairs(14) tubes are/were NOS/NIB for this 19 tube lot.
All NOS tubes tested new in the range on a TV7D/U with on average readings
for Gm between 64-68 range and Plate Current Emissions range from 50-72 mA.
6 of the 7 pairs were sold on ebay in Dec. 2023 for $450.00 per pair with excellent buyer feedback.
Two of the 19 tested below factory new but still good and we are listing these 2 singles on ebay.
TV-7D/U tested with Matched Gm&mA plates
Tube 1 ('5 23'):
Transconductance Gm =56.9/57.5 = 7,112.5 / 7,187.5 uMhos
mA = 50.2 / 50.1 mA Plate Current emissions
TV7U/AU/BU/CU/DU- Settings
| 5998 |
6.3 |
HY4-5062 |
63 |
- |
D |
3 |
40 |
Triode #1. |
| 5998 |
6.3 |
HY1-2035 |
63 |
- |
D |
3 |
40 |
Triode #2. |
| 421A |
6.3 |
HY4-5062 |
63 |
- |
D |
3 |
40 |
Triode #1. |
| 421A |
6.3 |
HY1-2035 |
63 |
- |
D |
3 |
40 |
Triode #2. |
WE PACK VERY WELL AND SHIP FAST WORLD WIDE TO OVER 100 COUNTRIES.
WE SHIP TO ALL 50 USA STATES, PO BOXES/APO/FPO BOXES AND ALL US TERRITORIES
INTERNATIONAL SHIP: VIA EBAY INTERNATIONALSHIPING LOW COST SPACE AVAILABLE AIR-FREIGHT
ALLOW 10 DAYS TO 6-WEEKS DELIVERY TO OVER 100 COUNTRIES.