Increase Les Lius Boost Gain

[Dulouz]

I built the Lovepedal Les Lius layout from the blog and it sounds REALLY good.

However, as others have noted the boost is very subtle. Is there an easy way that I can increase the output on that side?

[induction]

The boost switch works by reducing the emitter resistor, which increases the voltage gain. With the boost knob all the way up, the resistor is essentially reduced to zero. So it can't get any lower. Most of the play is in the last 10% of the knob. A reverse log pot would probably work better here.

Any simple component swaps you do to increase gain would also change the sound of the non-boosted mode. If you don't mind that, you could experiment with higher hfe transistors (say 2N5089, MPSA18, MPSA13, etc.). Or you could put a separate boost circuit before or after it, depending on whether you want more distortion or more volume, respectively.

There are some things you could do to get more boost. They are fairly simple, and you could do them without changing the layout very much. You would just replace some components with a switch and mount some resistors or diodes directly on the switch.

For more volume:
1. remove D1 and D2 (put them on an SPST switch, say). You'll get a volume boost, but the distortion will be reduced.
or
2. Add a resistor (experiment with the value, start with 47k, say) on an SPDT between volume lug 1 and ground (the other mode of the switch should short to ground). This will give you a preset volume cut. It will give you two modes, but no extra boost beyond what the pedal already delivers.

For more distortion:
1. Swap the 3k3 with a higher value (try 4k7 to 47k, or higher), for a full range boost.
or
2. Reduce the 3M3 to 2M2 or 1M, for more of a treble boost.

Some of these mods will give more bang with a higher hfe transistor. I would try that first. It might do the trick all by itself.

You could do any of these separately or in combination, but to know what you like best, you'll have to break out the breadboard. Whatever you like best, you'll also have to decide what to do with the existing boost mode. You can remove it in favor of one or more of the above, or you can combine it with one of the above. Again, the breadboard is your friend here.

The jfet and voltage regulator in this thing are really unnecessary, btw. They are just being used as a switch, and could easily be replaced with, you know, a switch. The rest of the circuit is just a variation on an electra (ie it's essentially a Cot-50, with extra options for the clipping diodes).