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previous: Graywater Josh,The B supply c... -- 8/31/2000 5:36 PM View Thread

Re: getting "sag" with resistors

9/2/2000 7:35 PM
Wild Bill
Re: getting "sag" with resistors
Josh, to elaborate on GW's post, the "sag" through a tube rectifier is there no matter how strong the PS may be. Also, the voltage drop is a function of the current drawn through the tube rectifier. If you're measuring it at idle you'll see little drop in B+. Feed in a test oscillator (you might want to consider a dummy load to spare your ears!) and measure when you dime the amp and with the volume all the way down. This will be your "sag".  
GW's also right that mfg's seemed to avoid telling you the amount of drop for each rectifier tube. I've got an old brochure/catalogue from Westinghouse that gives the drop. I think the Triode Electronics tube data page sometimes gives that imformation as well.  
 
Good luck!  
 
---Wild Bill