Jordan BossTone mods

[alparent]

I'm building a Jordan BossTone and I want to put a switch to take the clipping diodes in and out of the circuit.
When I do take them out I have a higher gain then when they are in (I know that part)

My question is what can I do to have an equal gain....either they are in or out ?
Can I add a resistor somewhere ?  Any help will be greatly appreciated.
Also an explanation of why I would add whatever, wherever is always nice (so I can educate myself  )

I'm using GGG schematic.

[aron]

When you switch out the diodes, switch in a trim pot wired as a volume pot OR, switch in a resistor that is in series with the output volume pot. The series resistor value will be determined by first wiring a pot (wiper and outer lug) in series with the volume pot, then dialing in the correct level. Then take the pot out, and measure the value in ohms between the wiper and outer lug. Replace with a fixed resistor of closest value.

[alparent]

Simple enough.

Thanks a lot Aron

[Mark Hammer]

Here is what you will end up with Alain.  You will have a DPDT toggle, with the common of each set of contacts tied to the .02uf cap coming from Q2.  As Aron suggested, you will have a fixed resistor of some value (or maybe a trimpot) in series with the input lug of the volume pot.  In one position, the switch will connect those diodes to the junction of the .02uf cap and the new added resistor.  When the diodes to ground are disconnected, the max volume will not be limited by the diodes so the pedal will be louder.  In which case, you want the extra resistance in series with the volume pot to attenuate the signal a bit.  When the diodes are connected, the volume will be limited by them, so you want a straight-wire shunt across the added resistor so that max volume is restored.

So, to recap, one side of the switch lifts and connects the diodes from circuit, and the other side of the switch adds and lifts a wire bypass around the added resistor.

I've used this system before, and it works great.  The trick is to find just exactly how much attenuation needs to be introduced when the diodes are lifted.  But I guess that is where a trimpot comes in handy.

[alparent]

OK thanks Mark.
Not sure yet what I'll do? I tried a switch between the 2 silicone diode and 3 germanium (not enough difference that would justify a switch).

Now I'm trying 2 silicone vs no clipping but it's hard ti judge the difference with the gain change. Will do the resistor thing and then re-evaluate. 

I'm also going to try with LED's.

Don't know why but I really want a switch there that will give me 2 different kind of fuzz. (Any suggestions?)

Side question.......what's the difference between fuzz/distortion/overdrive ?

Thanks to you both Mark and Aron.

[Mark Hammer]

Side question.......what's the difference between fuzz/distortion/overdrive ?

Don't get me started.....    
There has been much written here about that distinction, so I won't repeat it.  Trust me, search and you will find.

The only thing I will say at this point is that if it's something you could not imagine doing anything other than single note runs with, then it is likely a fuzz.  Whatever absolutely meets the aural criteria for "fuzz" is generally something so over the top that chords are a non-starter.  That is not to say that it can only be a fuzz if it meets that criteria.  Rather, if chords (other than the intro to Smoke on the Water) are not going to fly with that circuit, it is a fuzz.

[alparent]

OK I will do a search (I usually always do search) but I was sure there was a clear distinction and explanation that only I didn't know about. 

[brett]

Hi
the difference between 2 x silicon diode clipping (1.5V p-p) and power supply clipping (8V p-p) is about 5x.
You can easily add a switchable voltage divider to ground (before the volume pot) to adjust for this.
The impedance should be higher than the output of the effect (typically 1k to 10k) and lower than the volume pot (typically 50k to 500k).
A 25k ohms trimpot to ground is a good bet, with the wiper about 4/5 of the way towards ground and connected to the volume pot..
Switch it in and out as described above.
cheers   

[alparent]

Thanks brett!