Description
This sale is for THREE (3) TUBES, aka Valves(UK), Lamps(EEU), Rohren(DE) Quantity THREE (3), Tested Very Strong Gm & mA , Date Coded A4 E5 K4 1944-45 Production, Model : SYLVANIA VT-231 JAN-CHS-6SN7GT MIL-SPEC TUBES - All 3 tubes have internal/external identical construction, Production dates A 4 E 5 K 4- 2 tested above average factory new for Gm&mA with Balanced Plates, 3rd Tube also just below ave factory new.- BLACK PLATES, Copper Support Rods- Tall Glass Envelopes- 6 sided Solid Metal Foil bottom Getter - Glass etched with Octangle Stop Sign inside 6SN7GT below A 4 & E 5 K 4- 270 degree circular bottom of glass flashing (Medium, Mu 20/20 Twin/Double Triodes)- A 4 & K 4 have white hot ink stamped on Black Micanol base SC966A inside rectangle- E 5 Tube has hot green inked stamped SC966A inside a rectangle . Believed to be a US Military contract #. - White & Green Ink hot stamped on black Micanol base VT-231 JAN-CHS-6SN7GT Sylvania(JAN=Joint Army/NavyCHS= Contract Hytron-Sylvania), Made in the U.S.A. SC966A - No Original Boxes, Tubes will ship in new Westinghouse boxes with a printed copy of this description and test results. Condition: Lightly Used but Tested above Average Factory new for Gm&mA ,Seller reconditioned: Cleaned Pins & Glass Plug-in and Play to Listen condition.RE-Tested Strong in uMhos Transconductance (Gm) & Anode Plate Current in mA. Both with Balanced Plates and above average factory new ratings when tested at 150VDC Plate Supply Voltage. Our Test bench: Dan Nelson recent (07/24/2023) Restored, Upgraded & Calibrated TV7D/U with Digital Meter reading Transconductance(Gm) and mA (Anode plate current). TEST RESULTS: (Tested at 150VDC Plate Supply Voltage) NO SHORTS, NO LEAKAGES, NO GAS, NO Apparent Micro-phonics detected. Min. Good (60-65% tube life)TV7 METER READING OF 50/50 = 1,250/1,250 uMhos Gm.Bogey = Pulled from 5 Vintage Manufacturers Factory Data sheet specs (RCA,GE,Sylvania-Hytron, BRIMAR & Tung-Sol) for VT-231 6SN7GT tube type when tested as a Single Tube at Plate Supply Voltage of 250Voltsin Class A1 operations states Average Operating Characteristics NOS tube will test at 2,600/2,600 uMhos (Gm) at 9.0/9.0 mA Anode Plate Current. When Tested at a range of 100VDC-150VDC Plate Supply Voltage( All TV7 versions test at 150VDC Plate supply voltage)a VT-231 JAN-CRC-6SN7GT will test Factory NOS on average 2,500/2,500 Gm at 10.0/10.0 mA. (Where 2,500/2,500 uMhos (Gm) = TV7 Meter reading of 100/100. Tube 1: ( Date Code A 4 Jan 1944) ( 103/105% Gm, >100% plate current emissions) Plate 1: 103.0 = 2,575.0 uMhos(Gm) at 12.7 mA (Anode Plate Current) Place 2: 104.9 = 2,622.5 uMhos(Gm)at 12.9 mA (Anode Plate Current) Tube 2: ( Date Code E 5 May 1945 ) ( 112/112% Gm, >100% plate current emissions) Plate 1: 112.2 = 2,805.0 uMhos at 13.8 mA (Anode Plate Current) Plate 2: 112.8 = 2,820.0 uMhos at 14.0 mA (Anode Plate Current) Tube 3: ( Date Code K 4 Nov. 1944) ( 94-97% Gm, >100% plate current emissions) Plate 1: 97.1 = 2,427.5 uMhos at 12.1 mA (Anode Plate Current) Plate 2: 93.8 = 2,345.0 uMhos at 11.7 mA (Anode Plate Current) *** WE COMBINE SHIPPING on Multiple Tube Purchases for USA Shipping which SAVES $ on Shipping Costs which We refund at time of Payment. Contact us before you buy if you are International Customer for multiple purchased to be combined into One Box as we must make a new listing with all the items you want. WE PACK VERY WELL AND SHIP VERY FAST (one day or same day)ALL USA Locations : Low cost Shipping USPS Advantage (old 1st class ground/space available air) Low cost International shipping via eBay International Economy small package Service space available AIR-FREIGHT(allow 10days to 6weeks for delivery depending upon which World region box is delivered to). The Americas and Europe are fast.ASIA 2nd fastest. Austrialia /NZ / Pacific Islands about 3-4weeks delivery. West Asia/Middle East allow 6weeks.
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