Tweakeable layout for a Sola Tonebender

[angelodp]

Hi, I guess I am on a tear with this family of circuits. I am onto a 3 knob Sola Tonebender, also called Park. I am thinking of mixing some eyelets with turrets so that I can vary some componenets. I can also put in some trim pots.

I would love any suggestions from those that have built this particular circuit about potential components to vary. Since I tend to favor a smoother more sustainy sound, please keep that as a design direction.

[thetragichero]

fuzzcentral.ssguitar.com/3knob.php

has some different versions of it


if I follow your evolving circuits, fairly soon you'll be working on a big muff, eh?

[angelodp]

I have a Big Muff Pi NY model, sounds great. But its always fun to build these.

A

PS thoughts on tweak areas?

[thetragichero]

I have not messed with this specific circuit, but I'm a big fan of putting it on a breadboard and tweaking values until it does what I want it to do. pages like what I've linked give me idea of what can be changed and suggested values. add to that a basic idea of how too tweak transistor/op amp gain and this wonderful rc filter calculator (http://www.muzique.com/schem/filter.htm) and it almost seems like I have some clue about what I'm doing

[angelodp]

Sure thats what I am up to.


A question if you can. On the Vox version the input cap at the Q3 Transistor is 25uf electrolytic. On the traditional Mark 3 Tonebenders they show a .22uf non-electrolytic cap there. 
Is that larger cap allowing way more bass frequency in? 

[JohnH]

These circuits are well within range of modelling with Spice programs, freely downloadable. Examples are LTSpice, or my favourite: 5Spice. Youd be able to do small signal analysis to help understand and tweak the basic tones before distortion, and a transient analysis with sine waves to plot the distortion effects. I've found this to be very helpful in designing small circuits and modifying stomp boxes. You may need to go and find a PNP Germanium transistor model elsewhere online, but that should be easy to do.