a doubt on AD30VT

[Leo23]

for AD30VT, is there any way to know if the tube/valve needs replacement?

[cosmicrepairdude]

Sure, borrow one from another working tube amp, yours or a friend's and put it in and see if it improves things.
Or if you can find someone who has a tube tester, use that. Repair shops probably have them.

[Voxman]

The tube will usually last the lifetime of the amp. It's used quite differently to a tube in an al-valve amp and has way less voltage/current going through it. If the tube goes, your amp will be dead!

The tubes in my AD120VTX (7 yrs old) and Marshall Valvestate (16yrs old) are all original, & all working perfectly.

[Leo23]

The tube will usually last the lifetime of the amp. It's used quite differently to a tube in an al-valve amp and has way less voltage/current going through it. If the tube goes, your amp will be dead!

The tubes in my AD120VTX (7 yrs old) and Marshall Valvestate (16yrs old) are all original, & all working perfectly.

thanks! that's really helpful! I was looking forward to get the tube replaced by ignorance. I don't know much about circuits and I thought the amp could still work without the tube, as it's not an all-valve amp.

[edgelite]

I just swapped my stock tube out last night.
My friend has a tube tester and sure enough it was bad.
It just made a funny noise a couple nights ago and then lost it's mojo.
It still worked but the magic was gone. It would break up when pushed and in general just sounded lousy.
I tried 6 tubes and found the Bugera 12AX7A which is suppose be the same as a Ruby to be the best( of the ones I tried) . A lot of people seem to like the Ruby 12AX7 HG on this forum.
Just order one from The Tube Store or Musiciansfriend. It is worth it just to try.
It's harder to change on the AD30VT then my AD50VT but it's not that bad and there is a how to on youtube.