[Amps] New Guy, Old 813 amp

[Gudguyham at aol.com]

Scott, welcome aboard.  To my knowledge there were very few commercial  
amplifiers built with 813 tubes.  The ones that were built I do not believe  had 
any tuned input circuits.  The 813 is an older tube and was used in the  days 
when exciters were "loaded up".  These exciters would match a wide  band of 
impedance and therefore input circuits were not needed and  consequently not used 
in older amps.  Of course you could build your own  tuned input network using 
some mica caps and some small tuned input coils.   Perhaps someone has the 
data on them here, but I doubt you will find anything  that has been commercially 
made.  The 813 tube was widely used in homebrew  amps and most likely someone 
here may have built some input circuits and can  help you.  Lou



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