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Transformer PI Questions


 :
5/22/2000 4:05 AM
Morris Transformer PI Questions
Greetings all. I'm going to try a transformer for phase inversion, just for kicks. The transformer is a single plate primary to center-tapped push-pull secondary; 1:1/1 ratio. I'll be using it to drive a pair of cathode-biased EL84's connected in UL to a Magnequest OT.  
 
Question 1: Can I assume the impedance ratio of this transformer is 1:1? If I ground the center tap of the secondary and connect the other secondary leads directly to the grids of the EL84's with no additional loading, what would the reflected impedance be on the primary of the transformer?  
 
Question 2: If I reach an operating point where the grids of the EL84's want to conduct, won't the impedance at the grids fall through the floor? If so, how will this affect the reflected impedance back at the primary?  
 
Question 3: Any general suggestions on how to properly set this up are much appreciated. What driver tubes should I use; I've got 6SL7's and 6SN7's here? Should I parallel the driver twin triode?  
 
Thanks in advance for all your help!  
 

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