• WARNING: Tube/Valve amplifiers use potentially LETHAL HIGH VOLTAGES.
    Building, troubleshooting and testing of these amplifiers should only be
    performed by someone who is thoroughly familiar with
    the safety precautions around high voltages.

Deriving Secondary Voltages

Status
This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.
Hi:

I've been reading with great interest Mohan Varkey's reply to a post on this forum regarding the Powers PP6B4g design. I am facing a somewhat similar dilemma as I would like to drop the voltage to an input stage, but doing so requires a 10K resistor. Mohan remarked that this would slow transient response somewhat and suggested deriving secondary voltage from the center tap of the power supply. What I tried on my breadboard is a full wave bridge connected to both legs of the secondary, the remaining "+" side of the bridge to a choke input and center tap to a pi filter to the input stage. It works wonderfully, too much so in fact as it doubled my B+ voltage and put B++ where B+ had been.

My question is if there is any other method to derive a secondary voltage less than what I got? Transformer is 375-0-375 and I was hoping for a B+ around 350v and B++ no more than say 250v. If that's not possible is some other way around the big dropping resistor?

Thanks

Andrew
 
Status
This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.