GE 6146B 8298A Vintage NOS Ham Radio Transmitter Amplifier Tube Pair
Test Results are available upon request if not photographed in the listing or already stated. 90 % of our tubes are Tv7 tested. The tv7 tester has been around a long time and is a trusted tester. Military standards were tubes needed to meet 60% (minimum value) There isn't a specific percentage or data set anywhere that universally designates a vacuum tube as "new old stock" when using a tester nor for what test result is given. The best way is to calculate the GM - and check the data sheet for each tube - a nos tube should typically measure between the average and maximum micromhos(GM).
Tubes do not give the same reading across testsrs - even the same model tester will give a different reading sometimes. When testing vacuum tubes, testers typically measure various parameters like emission, transconductance, and leakage. Tubes that test within certain specifications may be considered good or usable, but whether they are specifically labeled as "new old stock" depends more on their history and how they were acquired than on the test results alone. NOS is subject to interpretation and there is no specific definition for it either. There are suggestions and opinions. All our tubes have been tested for. GAS SHORTS TRANSCONDUCTANCE & EMISSIONS. If they are listed they have none of the aforementioned. Please see my notes on noise tests below.We have a few different testers available to ensure the quality of the tube (as some tubes can not be tested on the tv7). Tv7 testing is tedious and I spend 12-13 hours a day testing tubes and double testing tubes - if you notice a mistake(like a picture doesn't match the title) please be gracious and let me know. UNLESS PHOTOGRAPHED WITH THE ORIGINAL BOX- tube will come in repackaged white boxes- 50-90 year old cardboard packaging doesn't hold together well. We have over the last 20 years amassed a huge collection of vintage amps/ parts / tubes and have decided to downsize that collection. Every tube has been marked for tracking and security purposes - these marks wipe off easily and without the mark no return will be accepted.
Sound quality is tremendously SUBJECTIVE. This is a very marginal test, only for. This test needs sound amplification; hearing listening to noise with headphones would indicate a real disaster inside a tube (THE shorts test WOULD already BE evidence OF THIS). There is nothing wrong with performing that noise test. This test is not going to tell you whether the tube will be silent in your SET (single ended triode) amp or in anything else. Ultimately, the best way of testing a tube for microphonics is in an actual chassis or amplifier similar to one in which it is intended to be used.
