Replacing tubes....

I soon will be inheriting a Bel Canto tube pre and amp...however...the tubes are probably pushing 20 yrs I need to replace them? and so...with what?
You really only need to replace them if they are bad. (Noisy, maybe microphonic). Most of the tubes I use were made in the 1940's and 50's, so age alone does not matter.

To help you pick some replacements, what kind of tubes does this specific gear take??
Unfortunately, you can also have a tube that is definitely "bad" without it being all that ostentatious about it. After a while, they simply lose steam and sound flatter and more constricted -- it may not make noise or advertise the fact that it's on its way out to pasture, it just won't perform. (Or, you can have the noisy, drama queen tubes that bitch and hiss and spit and moan on their way out, which is nice only because it makes them a whole lot easier to single out and shoot). If you come into a full tubed setup of unidentifiable though likely considerable age, I would immediately assume that the tubes are suspect. If you plug it in and it works fine, without any extraneous pops or overbearing tube rush or the like, then hey, it works. Whether or not the tubes are really giving you all that the gear is capable of, however, is likely unknowable without some context to compare them to. I’d say, if it works and makes you happy, let it. Full stop. If it immediately sounds flat, constricted, thin, anemic or something like that, then I’d suspect the tubes. Eventually, you’ll have to get some new glass for it, and the only way I know to see whether replacement tubes sound better (and, deductively, to guess whether the old ones were running out of gas) is to try it. It’s sometimes nice to have a replacement set on hand, just in case. If that’s practical at all, it might be worth doing sooner rather than later. Get used to the sound of the old ones for a bit (assuming there’s no immediately evident problem) and then switch out the full set for the spares. If you have a preference, go with it. If not, put the originals back in and rest assured that you’ve got reliable backup when you need it. If you notice that there are some things that are better and some that are worse depending on what tubes are in the system and begin to rolling more and more tubes in search of the prefect balance, then you’re in trouble and I wish you luck.
tubes are not all that expensive. There are great tube suppliers on the internet. If you are inheriting and you want to put something of yourself into the gift, replace all of the tubes and keep the originals for back-up.

i just did this....eight tubes for about $140.00.

I feel good, too.