Adding Volume and Gain Controls to Single Tube Preamp

[portersage]

Hi there, I’ve been tinkering around with an old GE 6SC7 tube phono / mic preamp and am wondering what the best way to add both a volume and a gain control into this circuit. Currently I have the main volume pot wired at the first grid of the tube, which works great, and I’m able to take it from clean and quiet to completely overdriven with it, but when it’s cranked, the output level is wayyyyy too high for it to be usable for me. How should I add a master volume while keeping the gain characteristic of the overdriven circuit? Any input is greatly appreciated thanks!

 

[ruffrecords]

You cannot really alter the gain of the two tube stages because they work together with the negative feedback to provide the correct phono response. You could add a level/volume control at the output. Say a 500K pot from the right of c4 to ground with the output then taken from the wiper.

Cheers

ian