Mix knob / add on to clean signal

[Tune Tone]

Hey
Im building some effects for a while. some from kits, some from here.
I tried to look up the forum for what I think might be a simple off board wiring thing. Specially when comes to boosters for examples. I build range master from a kit which sounds terrific. What bothers me is that the volume sounds similar to the clean signal only when the knob is turned up from let's say 12 o'clock. and when its on 0 there is no signal coming out... I wired the effect in a most common true bypass way. I want to do it in a way that the effect is on will only add on to the clean signal the booster treble.

For overdrives I think it could be cool when using bass so you always have a mix knob for the clean signal and in this way there is no low end loss (maybe in some effects also good for guitar cause many O.D dry out the 'body thickness'' of the Guitar tone).. anyway I am sure most of you know what I'm talking about.

so any forwarding to good reads and tutorials or previous posts on this matter would be highly appreciated!

thank's!!

[nocentelli]

I think you are describing two different issues - The first is the output level of the effect when compared to the bypassed aka clean guitar level, the second is the issue of blending in some of the clean signal with the effect signal. You do not usually solve the first problem, that is wanting to increase the minimum volume of a booster effect, by mixing in clean signal.

To increase the minimum level of a pedal with a boost control potentiometer, you would usually first identify how the pot actually controls the signal level, and put an appropriately sized resistor in series with one lug of the pot to increase the lowest output settting from silence to unity (bypass) level. In the range master, the boost pot is actually the collector resistor (lug 1 and 3), and the wiper output varies the level being sent to the output cap from loudest (wiper shorted to lug3) to silence (wiper shorted to +9v, which has the equivalent effect to "grounding" the audio signal). If you placed a resistor between +9v and lug 1, it would prevent the pot cutting the output completely, and the exact level at minimum would be set by value of this fixed resistor, e.g. fixed resistor = pot= 10k, minimum volume is around half that of maximum. What messes this up is that altering the total series resistance from +9v to collector by adding a resistor will affect the bias, and it might sound poor/not pass signal.

You could use a 5k resistor plus a 5k pot, and see whether it's close enough to unity, or if it's too loud, just pad the output with another fixed resistor between lug 2 and the output cap.

A simpler way would actually be to replace the pot with a fixed resistor of 10k, connect the output cap direct to the collector, then put the pot back on the end wired as a normal volume pot: then you can add a "set and forget" 20k/50k trimmer to set the minimum setting exactly to unity without messing with the bias.

Blending in clean is a different matter, there is a JFET blend vero here at tagboardfx, but it's more suitable for chorus, phaser, flanges etc, ie. effects that output at unity gain, so the blend control is smooth from totally dry to totally wet with no unevenness in volume level. For an overdrive, two separate "clean" and "overdrive" level pots tends to make it easier to get the correct blend; I don't see any advantage of adding a clean blend to a treble booster, if it's too treble/bright/effected you can just increase the value of the input cap to bring some low end back in.