Hi there. This is probably the wrong location for your post -- one of our moderators will likely move it.
Couple of questions for you: Is there a problem with your amp? Is it operating well, or are you trying to correct a problem? Or are you just trying to do maintenance?
I'm not personally well acquainted with this amp, but the schematic we have shows a of quad EL-34 tubes, 1 12AX7, a pair of 12AU7, and a 5U4 rectifier tube. Is this correct? Amplified Parts is saying that you need 6 12AX7 tubes, which seems unlikely to me -- but I may be looking at the wrong schematic. How many tubes are actually in your amp?
I looked at the brands Amplified Parts is offering, and I think there is not much difference between them. This is likely to be a controversial statement, to say the least. I personally prefer Sovtek, Mullard Reissue, and TAD as brands. BUT, are they really better than anything else? Probably not. I generally stay away from Chinese tubes, but I am sure there some quality built tubes from there as well.
I normally deal with Antique Electronic Supply, which I think is the same company as Amplified Parts, and have had great luck with their service. When I get a bum part, a phone call is all it takes to get a new one shipped pronto. That is the key for you.
If there is an actual problem with your amp, though, just throwing a bunch of new tubes may or may not solve the problem.