Aristo as such don't exist any more but the company that has taken over their business still makes new replacement tubes. Have a look at their web site for an archive of old Aristo products and info about their range of tubes.

My understanding (not based on experience) is that the old tubes were not so good for VC filter use but I have seen disagreement on this point.

http://www.light-sources.com/special...archive?page=1