[Hallicrafters] SX25 mods

[chandlerh2 at aol.com]

hello to all this is my 1st post here and i am somewhat of a novice working 
on these radios  but i do know enough to work on them . i love hallicrafters 
and have about 8 of them now all in working order including a mint SX24 and 
SX25. i have completely recapped my SX25 and one shematic i have shows to use a 
6AB7 in the 1st RF stage and also a 5Y3 rectifier tube instead of an 80 . are 
any mods necessary to use the 6AB7  and would i see any preformance gains ???  
any info would be appreciated  
thanks  steve