Hoffman Amplifiers Tube Amplifier Forum

Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: 6v6Pin1 on July 29, 2020, 11:27:05 am

Title: AB763 One Channel - Add a filter cap
Post by: 6v6Pin1 on July 29, 2020, 11:27:05 am

I have an unused 16uf/450v cap available on this build. I was thinking about adding a 1k resistor and the filter cap to create an E power node.
Which triode(s) would benefit most from being moved to the E power node?
https://el34world.com/Hoffman/files/Hoffman_AB763_1.pdf

Title: Re: AB763 One Channel - Add a filter cap
Post by: sluckey on July 29, 2020, 11:31:37 am

I would power V1 from node E. Put resistor between node D and node E. You can use a larger resistor since the current is so small.

Title: Re: AB763 One Channel - Add a filter cap
Post by: 6v6Pin1 on July 29, 2020, 12:32:42 pm

Ok thanks! I'm going to try it out.
The V1 voltages are where I want them now. I don't want to drop too much. Is there a rule of thumb on how small that resistor can be?

Title: Re: AB763 One Channel - Add a filter cap
Post by: sluckey on July 29, 2020, 01:13:17 pm

My thumb says use the resistor value that gives you the node voltage you want.