What are used tubes worth ?

Why not look what the matching numbers are and order a new matching tube? Then you would have a backup set. I would email Jim Mcshane for the new tube.

Are you sure though that they are the original tubes and only have 800 to 1000 hours? If that is a VT 100 mk1 it is probably 18 years old.

Not much,just keep them for spares!

will it jeopardise sq if each new tube will have led display with hours?

It is a Mk II amplifier. The hours do sound low. I used the amp only a few hours per month. What can I say, I was busy with career and raising 3 kids, so I had very little time to listen to it. Anyway, I sold the amp, but still have these tubes.