[Amps] Drake L4/L4-B tube replacement - 3-400Z or 3-500Z or 3-500ZG

[Jason Buchanan]

Not to beat a dead horse but is there any benefit to plugging 3-500ZG 
tubes in a stock Drake L4 or L4-B?  Is the stock Drake power supply 
sudsy enough to show any benefit to using the bigger tubes or is a 
3-400Z the limit the power supply can provide for?  I noticed the 
amplification factor for the 3-400Z is 200 where it is 130 or less for 
the 3-500Z and 3-500ZG tubes.  thanks..........