[Harp-L] need advice re Princeton amp tube substitution

[Captron100@xxxxxxx]

I'd like to ready my guitar amp for playing harp thru it.  I've  written a 
long email describing what tubes my amp has in it.  For  some reason the mail 
keeps getting bounced.  Suffice to say that from my  readings i gather that the 
Princeton amp's preamp seems share tubes for  different puposes.
  Can anyone tell me specifically which tube or tubes i would need to  sub in 
my 1974 Fender Princeton amp, and the tube or tubes of choice?   Any other 
suggestions will be appreciated.  TIA
ron