# Cathode Biased 5F10?



## ampaholic (Sep 19, 2006)

I'm working on a "from-scratch" build of a Harvard 5F10 circuit complete with the 6AT6 preamp tube. The power transformer I am using is from an old mono 6V6 tube stereo however it does not have a bias tap.
My thought is to cathode bias the output tubes and essentially copy the 5E3 circuit. Two questions; does anyone foresee a problem doing this and; is a 5 watt cathode resistor rugged enough?
Thanks!


----------



## WCGill (Mar 27, 2009)

A 5w resistor should be fine. If you really want fixed bias, you can derive your bias voltage from the HT with a voltage divider.


----------



## ampaholic (Sep 19, 2006)

WCGill said:


> If you really want fixed bias, you can derive your bias voltage from the HT with a voltage divider.


True enough, and I guess that would better demonstrate the 5F10 circuit. Otherwise all I have is a tweed deluxe with a funny preamp tube!
Would the Princeton Reverb voltage divider bias circuit be a good place to start (less the intensity control)?


----------



## WCGill (Mar 27, 2009)

ampaholic said:


> Would the Princeton Reverb voltage divider bias circuit be a good place to start (less the intensity control)?


The Princeton, Princeton Reverb and Tremolux bias circuits are similar. Just change your resistor values to get the required negative voltage.


----------

