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6AS7G produced by General Electric Owensborough, USA in 1957
This is a beautiful matched pair of NOS/NIB 6AS7G tubes.The tubes are made by General Electric in the Owensborough plant, USA. Both tubes are made in week 35 1957. Coke bottle with D-getters in the base and copper grid posts.
The 6AS7G is a double triode with special properties. The AC anode resistance is very low at 280 Ohms and the mutual conductance is considerable at 7 mA/V. This valve can be used in low voltage power supplies as a series pass device or it could be used for a direct drive audio amplifier. The literature mentions a single ended audio amplifier as its use. The earliest reference of this tube was in the 1950 RCA data book.
This version of the 6AS7G is highly regarded for use in OTL amplifiers (e.g. Atma-Sphere) and headphone amplifiers. I refer to the threads on the web for more information.
I had the opportunity to obtain a number of these tubes and this enabled me to select a nice matched pair. The tubes have a coke bottle shape, black plates and two bottom D-getters with a beautiful flash.The tubes are thoroughly tested. Both tubes have excellent test values that match the factory specification well and balanced systems.
Sonics
Note from the WEB: All highs, mids and lows in perfect balance and a rich creamy presentation and mid-range! Big clean and clear bold sound. Sweet and creamy at the same time.
Note: my tubes are often not the cheapest. But is hard to find better tubes !
Test equipment & method
Test equipment: AVO Mk IV, Utracer 3+, Philips 1532, RFT stabilised power supply, 2x Korad KA3005P programmable power supply and 2x Keithley 2700 and AVO Valve Data Manual 23rd edition 1981.
Gas and shorts were tested with: AVO Mk IV. Ia & transconductance are measured conform the official factory specification (see picture) with a cathode resistor (metal film). Precision of the test voltage is: ± 1%. Measurement after 10 minutes stabilization.
Test results*
| Valve 1
V3 |
Ia (plate current):
Transconductance (Gm): Gas test, Shorts test: |
120 /113 mA
7,2 /7,0 mA/V OK |
= NOS / NOS
= NOS / NOS
|
| Valve 2
V22 |
Ia (plate current):
Transconductance (Gm): Gas test, Shorts test: |
124 /126 mA
7,0 /7,0 mA/V OK |
= NOS / NOS
= NOS / NOS
|
Ia: New is 125 mA. Gm: New is 7 mA/V (see datasheet) A valve is assumed to have NOS specs if both; emission and Gm are 90% of the rated value or more.
Please read our test notes and shipping policy before buying !
Short description
| Tube type | 6AS7G |
| Quantity of Tubes | One pair |
| Brand | General Electric |
| Manufactured in | USA |
| Date codes | 57-35 & 57-35 (1957 week 35) |
| Construction | Black plates, copper grid posts |
| Getter Construction | Two Bottom D-getters |
| Print Condition | NEW, See pictures |
| Box included | Original GE box (see pictures) |
| Equivalent tubes: | 6080, ECC230, 6AS7GA |
| General test results | NOS |
