I replaced tubes in my Ampeg SVT CL a while back. I had one tube burn out, and I ended up replacing the complete set. This is what I took out which is (5) 6550's, (2) 12AU7's, and (3)12AX7's. You would just need one more 6550 if you are putting them in an SVT. Overall they're in decent shape. Sounded good before I replaced them, just wanted to switch it up and put new JJ's in it at the time. Now sold my SVT so I don't have any use for them. Each tube is labeled with type and where it was in the SVT. *They are in JJ boxes, but are Ruby tubes. Make an offer if you have use for them. Thanks.