[landgreen]

I'm new to the tube crowd and enjoying my month old WA2, T1 combination greatly. Listening to Eric Clapton's "Me and Mr Johnson" last night was really engaging. My question is as I start to try different tubes, what does matched tubes actually mean. Is it that they test the same or how would I know that tubes, say a pair of Tung-Sol 5998s, are actually a matched pair?
Thanks
Blair

 

[Skylab]

A truly "matched pair" would mean that they are matched on a series of tests that, frankly, the majority of people, even people like me with tube testers, cannot perform with the testers most commonly available.  I can use my tester to check that the transconductance matches, and that's useful, but not 100% complete.
 
Also, how critical this really is depends heavily on the circuit it's being used for.  I have not found exact tube matching to be very important in my WA2.

 

[landgreen]

Thanks Skylab.
So to make sure I've got this right, as long as I find 2 same  tubes ie Tung-Sol 5998 that test well and about the same, it would be a reasonably safe purchase?
Regards
Blair

 

[Skylab]

For the WA2, yes.

 

[landgreen]

Thanks again. Things aren't always so obvious for new tube people as for those of you that have been at it for a while. I've had some great help from a few people now who frequent this forum which is much appreciated.
Cheers

 

[rosgr63]

To keep it simple, plate current matching at any respectable "real-world" operating parameters is adequate.