Tone & Tone Stack

This point has taken a lot of time and effort, but there is a clear result. For midrange sound use a tone control, which mainly serves as a highcut and already works in the mid region. You are more flexible with a tone stack, which effectively reduces feedback because its midrange notch.

Tone control

There are many circuit configurations that are usually based on the "Tweed tone control".

I only use a potentiometer and a capacitor between the output of the first tube and the volume. The function to turn up the treble frequencies with a "Bright" control is unnecessary in my mind, as long as you have set the control path of the volume potentiometer in a reasonable way.

The value of the potentiometer can be adapted to the desired control path, the value of capacitor controls the cutoff frequency. With my values, I am generally between the plans of the "Lone Wolf Blues Co." which engages too little in my mind and go up to the solution of Harp Gear, which makes it pretty muffled.

The BigMuff control at the Weber 5F2h is not an advantage. Certainly not as it is sold.

Tone Stack

The tone stack takes its name probably from the stacked capacitors (or potentiometers) in the circuit diagram. There have already been sound schemes with three controllers in the 50s, the "Fender stack" has prevailed in the 60's and was rebuilt with some changes by Mashall and Vox. For audio applications, this scheme would not be suitable, because you can not achieve a linear position. The mids are always lowered.

The tone stack on the right has proven itself for harp and although only two values got changed, it works!

You can identify the different frequency responses with the Duncan ToneStack Calculator, but to be honest, what for? Who knows the meaning of one millimeter on the graphic to the hearing impression. But I can tell from experiments that a shift to the right leads to more bass volume, but also to feedback in this area. On the right side, it behaves a bit different. The red line is series, the green is the changed stack, the controls are set "harp specific" and you come from a low-impedance source such as the Bassman.