Tone Controls

[Bone]

I want to build a tube preamp/tone control for my SS power amp.
What style of tone control would be best for a bass, Baxandall/james with flat output with the controls at mid, or Fender/Marshall with the mid frequency scoop?
Personally I'm tending towards the baxandall/James but what do you think?

Tony.

[xgsjx]

There isn't a "best", it's what type You prefer.
If I had the knowledge to do what you're doing, then I would likely look at having bass, mid & treble controls.

I'm sure someone with better knowledge on this than me will be along to give some helpful advice.

Welcome to the forum.

[Subthumper]

Download the tonestack calculator from the Duncan amps page. It's got most of the permutations of tone controls for tube preamps and let's you virtually alter the values and shows a visual graph of the predicted frequency response. Not many give a true flat response except the James circuit which doesn't have a mid control. Most of fender/marshall circuits are quite mid scooped.
Good luck.

[bertbass]

Why not build in both and have them switchable, then you'll have the best of both worlds and also the option of bypassing the EQ altogether.

[Chienmortbb]

The so called FMV (Fendrer Marshall Vox) stack is not very versatile as they are passive but then if you are building a Valve pre then maybe that is OK. The Fender stack will give a result like a Fender Bassman. One problem with the Fender stack is that it is possible to kill the volume with the wrong pot setting, not a good idea on a dark stage.. The Vox version is quite inflexible and of these the Marshall is the best bet of the three.

Again the James would be the choice for a simple Bass & Treble control, Baxandall needs to be included in the feedback loop of an amplified stage so will add to the number of valves.

One comment, most of the Valve sound comes from the power amp and power supply, is it worth putting valves in the peamp?