[Hammarlund] Tube Source Needed

[Eugene Balinski]

Listers,

   I know that this has been covered before, but I
misplaced the message(s).  

   Can someone recommend a good source of tubes ?  
My HQ-180 is going to need a few.   I would prefer 
NOS - RCA, Sylvania, GE, etc.   

   Also, has anyone noticed any performance differences
between the various tube brands ?  Is there a particular
tube that will not perform well in a given Hammarlund (HQ-180 AC)
application ?

   Thanks in advance for any/all help.

   Gene K1NR/3