Question about tubes

Hello AG folks hoping someone can help me out. I have a Magnum Dynalab MD 109t not the SE version. It takes 4 JJ 6922 Goldpins (what factory installs) . I want to order a new complement of tubes. Are all 4 exactly the same or is there a specific tube purpose I should be aware of such as power or signal etc. I am not versed on tubes. Factory wants $300 Tube Depot $96 bucks thus my question . Thank you in advance for any direction 

Jones