I've had a lot of fun with this build, its very versatile and effective, so thought I would share.
I built it into a joyo ultimate octave box, using the existing joyo footswitches and their PCB's and LED's. I have an old amp from the late 1960's which has baxandall tone controls, which when set flat, seem to give a flat freq response, so I use the Tonemender to scoop the mids a bit and fine tune the bass and treble.
The boost part is a mod and to do that I put an LDR in parallel with the 4K7 resistor that sets the gain for U1b (the ratio of the 4K7 and the 500K level pot sets the gain). I used a 200K pot in series with a 22K resistor to feed 9V to the LED facing the LDR inside the black heatshrink. I can have the Tonemender running and hit the boost footswitch for a pre-dialled boost, for a lead solo for example.
Tonemender schematic (http://www.runoffgroove.com/tonemender.html)
(https://dl.dropbox.com/u/61170900/Tonemender7.JPG)
Sorry 'bout the graphics - I'm working on that, truly I am (yeah right...)
A gut shot here (https://dl.dropbox.com/u/61170900/Tonemender5.JPG) and another one. (https://dl.dropbox.com/u/61170900/Tonemender2.JPG)
The Tonemender is an example of a simple circuit that works really well, that you can't buy as far as I know, and has many uses, for example eq, boost, eq with boost, vol cut, overdrive with eq, or as a clean preamp to drive a poweramp.
I quite enjoy the bare-bones graphics. The opto-powered boost mode is a very elegant implementation. Well done!
I think I get the LDR setup but could you explain why you did it that way?
Thanks for the compliments Brian.
Quote from: Bill Mountain on June 19, 2012, 11:17:18 PM
I think I get the LDR setup but could you explain why you did it that way?
It's the easiest way I could think of, and no switching noise. If you have any suggestions though, I'm all ears.
I might have used a switch to swap the 4.7k resistor and a 5k pot. I'm no expert and the thought of using an LDR scares me so I never would have considered it.
Very nice
Quote from: Bill Mountain on June 20, 2012, 11:48:15 AM
I might have used a switch to swap the 4.7k resistor and a 5k pot.
Old topic, but I'm really interested in this mod. I would like to give at the Tonemender a gain pot control. Do somebody knows how it sounds.