A catalytic converter is a catalytic converter. Either it works or it doesn't. However, that is for cars. For electronics, if one doesn't have the money, you do the best you can and take your chances. Just make sure the supplier has a good warranty or return policy. Audio Research supplying the tubes will warranty the tubes and if their tubes blow prematurely and damage their equipment, they will stand by their products and repair it for minimal costs or free. I purchased a set of tubes for my VTM 120 monos and my PH3 phono stage and one of the 6922s from the VTM blew and took out the fuse also. Well, I replaced the fuse and put an older 6922 in to see if the amp was okay. It was. But, I called Audio Research and told them about the failed tube and they mailed me a replacement. I don't know. dealing with companies that stand behind their products mean a lot to me and eliminates a lot of grief. But, it does depend on your price point. Audio Research supplied tubes are more expensive.
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Enjoy