Hoffman Amplifiers Tube Amplifier Forum

Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: Bieworm on January 25, 2021, 11:02:30 am

Title: 1M Gain pot / voltage divider question
Post by: Bieworm on January 25, 2021, 11:02:30 am

To the more experienced here...

Between the 1st and the 2nd preamp stage I have put a 1M pot that serves voltage divider. Classic setup... 1st stage plate - .01uf cap - 1M pot divides voltage between grid 2 and ground. The 2nd stage is a parallel triode with cathodes splitted.
I find that on the 1st half of the pot there is too little low end. Is there a way to thicken the sound there without fattening it up too much on the 2nd half of the dial?

Title: Re: 1M Gain pot / voltage divider question
Post by: jordan86 on January 25, 2021, 11:10:23 am

A larger coupling cap coming off that first stage before the pot could help. .022 is common. Or a larger bypass cap at that first cathode. You may get too much low end with the gain higher though. Could correct it with a smaller coupling cap coming off the next stage plate.