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6AS7G produced by Chatham Electronics/ Tung-Sol in the USA; a matched pair !
Note: my tubes are often not the cheapest. But is hard to find better tubes !
This is a beautifull matched pair of NOS/NIB 6AS7G tubes.They are made by Chatham Electronics; a later subsidiary of Tung-Sol. The tubes are made in the same week for the Joined Army and Navy in 1955 and both packed in November 1955. In the box they are carefully wrapped in a cardboard envelope.
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 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.
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. Precision of the test voltages is 1 %. Measurement after 10 minutes stabilization.
Test results*
| Valve 1
V2 |
Ia (plate current):
Transconductance (Gm): Gas test, Shorts test: |
114 /117 mA
7,6 /7,4 mA/V OK |
= NOS / NOS
= NOS / NOS
|
| Valve 2
V11 |
Ia (plate current):
Transconductance (Gm): Gas test, Shorts test: |
121 /114 mA
7,6 /7,4 mA/V OK |
= NOS / NOS
= NOS / NOS
|
(Ia: New is 125 mA. Gm: New is 7 mA/V) 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 | Chatham/ Tung-Sol |
| Manufactured in | USA |
| Date codes | 544 & 544 (1955 week 44) Packed: 11/ 1955 |
| Construction | Black plates |
| Getter Construction | Two Bottom D-getters |
| Print Condition | NEW, See pictures |
| Box included | Original JAN box (see pictures) |
| Equivalent tubes: | 6080, ECC230, 6AS7GA |
| General test results | NOS |
