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previous: AMZ While working on some mods for a ty... -- 8/6/1999 12:39 PM view thread

Re: Tone Control mods

8/10/1999 11:53 PM
Re: Tone Control mods
Hi Jack,  
About a year ago I made up this little four-stage tube preamp for experimental purposes and as a learning tool. I wanted some type of tone control but didn't have room for the typical three-knob stack. So, I decided to use a single pot with a bass cap on one side and a treble cap on the other. Maybe it was a one meg pot, don't remember at the moment, but I had to put a series resistor with the bass cap and even a small resistor to ground to balance it better. If not, the bass side lets through a lot more signal and it just won't be balanced with the treble side. Of course, you knew that anyway. I may have even used an audio taper pot favoring the lesser value towards the treble, that way as you turned it towards bass, it wouldn't loose the treble so fast as in a linear pot from what I experienced.  
In the diagram at your link, maybe changing the 39k resistor on the bass side to something considerably larger would help out or take a resistor parallel with the .01uf cap to ground to get rid of some of the lower bass.  
I can tell you this much,that I experienced some darn good tones with that single pot and I will get into it more down the road. As I turned from the treble side to the bass side, somewhere in between I started to get some of the prettiest blues tones I've ever had personally. I actually placed one pot in between the first and second stage and also one between the third and fourth stage. That gave me a bit more overall control. I just want to get away from the same ole stacks, Marshall or Fender types.  
I was pleased to read your post about the subject. Hope you keep us updated. I will try to get back to my project someday soon, first have to get a couple of amps tweaked to my satisfaction.  
Take Care, T.B.  

AMZ Glad to hear of your positive exper... -- 8/11/1999 1:28 PM