[malcolmhead]

Hi

This is newbie question on sourcing tubes. I'm looking for Sylvania, RCA, Ken Rad tubes and found that a Ken Rad 6SN7GT can cost between few bucks (usually on eBay) to few hundred bucks (from tube dealers). Why the huge difference? Assuming a genuine deal, does the difference relates to the remaining useful lifespan of the tube?

Also usually, they will indicate some tester result such as:

"3000 to 3100 / triode 1, 2900 to 2950 / triode 2, in mutual conductance where 3400/3400 for Triode 1/Triode 2 is average new. No shorts."

So the question is how do we interpret this information? In this case, is it a good tube? It is a Sylvania JAN 6080 WB 6AS7G.

Please enlighten.
Thanks.

 

[malcolmhead]

To add on to my own question, may I know what below information means? Can anyone help to explain/interpret? What does the figure 70 mean?

EMISSIONS 89/84. MINIMUM GOOD IS 70.

Gm 114/111 SCALE 120.

Thanks in advance.