Description
GE 6SN7GT JAN military version!!
This is a pair of General Electric 6SN7GT tubes made in Canada. I refer to the many threads on the web for more information. The tubes are thoroughly tested and it have excellent electrical values (note test results below).
The tubes have excellent test values that match the factory specification and balanced systems.
A very nice early pair
Both tubes have some minor glue residues on the base; see pictures.
This pair is real history.
An equivalent pair branded GE is listed by me in another ad.
Sonics
Excellent preamp valve, super linear, low noise, very smooth extended highs, very good in phono stages. Open and airy top end.
> one of the oldest vintage 6SN7GT.
Factory Specification
See data sheets (last pictures)
Test method & results
Tested with: AVO CT-160 (Dutch army tester), AVO Valve Data Manual 23rd edition 1981, Utracer3+, Philips 1532, RFT stabilized power supply, 2x Korad KA3005P programmable power supply and 2x Keithley 2700. Gas and shorts tested with: AVO CT-160 (Dutch army tester) Setup: AVO Valve Data Manual 23rd edition 1981. Ia & mu are tested with the official factory test setup: Va = 250V and Vg = – 8V. Precision of the test voltages 2%; measurement after 10 minutes stabilization.
Test results*
| Valve 1
V27 |
Ia (anode current):
Transconductance (Gm): Gas test, Shorts test: Balance |
10,4/ 8,8
2,7/ 2,6 mA/V OK Platimum grade |
= NOS
= NOS
< 5% |
| Valve 2
V28 |
Mu (amplification):
Transconductance (Gm): Gas test, Shorts test: Balance |
7,7/7,4
2,4/ 2,5 mA/V OK Platimum grade |
= NOS
= STRONG
< 5% |
(Gm good from 2,1 mA/V, New is 2,5-2,7 mA/v)
Short description
| Tube type | 6SN7 GT |
| Quantity of Tubes | One pair |
| Brand | MARCONI |
| Manufactured in | Canada |
| Dates | code M5; 40’s |
| Construction | box plate |
| Getter Construction | D bottom-getter |
| Print Condition | good; see pictures |
| Box included | Vintage Marconi box |
| Equivalent tubes: | 6SN7, 5692, |
| General test results | Excellent |
