Description
GE 6SN7GTB brand new old stock in original boxes !!
Note: my tubes are often not the cheapest. But is hard to find better tubes !
This is a pair of NOS General Electric 6SN7GTB tubes made in OWENSBORO, KY USA. The properties of this tube are legendary and widely known. I refer to the many threads on the web for more information. The tubes is thoroughly tested and it have excellent electrical values (note test results below).
The printed code 5 – 52 188 – 5 the foot of both tubes indicates that the tubes were manufactured in 1955 in the OWENSBORO, KY plant in USA (codes see picture). The tubes have the typical side-getter plate structure with a beautiful flash. The tubes have excellent test values that match the factory specification and balanced systems.
This pair is a real jewel.
Sonics
Excellent preamp valve, super linear, low noise, very smooth extended highs, very good in phono stages. These have a helically wound filaments and are very low in hum. Open and airy top end.
> one of the best vintage 6SN7 types ever made.
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
V5 |
Ia (anode current):
Transconductance (Gm): Gas test, Shorts test: Balance |
8,2/ 8,5 mA
2,7/ 2,7 mA/V OK Platimum grade |
= NOS
< 5% |
| Valve 2
V6 |
Mu (amplification):
Transconductance (Gm): Gas test, Shorts test: Balance |
9,2/ 9,5 mA
2,8/ 2,7 mA/V OK Platimum grade |
= NOS
< 5% |
(Gm good from 2,1 mA/V, New is 2,5-2,7 mA/v)
* For test methods and factory specification read the tube testing page.
Short description
| Tube type | 6SN7 GTB |
| Quantity of Tubes | One pair |
| Brand | General Electric |
| Manufactured in | Owensboro, USA |
| Dates | week 52 1955 (5-52) |
| Construction | ribbed plate |
| Getter Construction | D side-getter |
| Print Condition | new; see pictures |
| Box included | Original GE box |
| Equivalent tubes: | 6SN7, 5692 |
| General test results | NOS NIB |
