Xotic BB Preamp

I really love the sound of this one.  I've seen two different diode arrangements, one with just two back to back which would be more compressed, and one with two series pairs, so I've included a switch so that you can choose either, and also have a centre diode lift mode for a cleanish boost. Info about the original:

The BB Preamp offers awide variety of sounds. It's capable of a 30dB+ clean boost with an adjustable ±15dB two band active EQ which adds a wide range of harmonic content to your ideal sound.
The BB also utilizes a pre-gain stage which allows the Pedal to go from a very pristine clean to a very smooth,compressed, overdriven sound.

Xotic RC Booster

Xotic write about their original:

The RC Booster offers a super transparent 20db+ clean boost with an adjustable ±15dB two band active EQ which adds a wide range of harmonic content to your ideal sound. As a clean boost, it can enhance other pedals, such as "overdrive and distortion pedals", or you can crank the gain for a "crunch" sound. But, the RC Booster is an extremely transparent, where many player's find they leave it on all the time.

And you can save a couple of rows if you want to by making up your own diode wrap rather than placing them individually on the board.  If you'd prefer to do that make up two 3-series 1N4148 diodes, wrap them in tape or shrink tube and solder them in as shown below.

Xotic AC Booster

Info from the manufacturer:

The AC Booster is a natural sounding "overdrive" pedal. Not "heavy" distortion, but a sweet thick overdrive with an "open" non-compressed feel. It's capable of a 20dB+ boost with an adjustable ±15dB two band active EQ which adds a wide range of harmonic content to your ideal sound

Xotic EP Booster

And the original version.  You can supply this with 18V if you want the extra headroom, but if you are likely to do that make sure you choose appropriately rated caps.  Xotic's info:

What do the tones of renowned guitarist such as Page, EVH and Johnson have in common? They all used the legendary echo machine EP-3 as a pre-amp.  We've captured that magic in a new Xotic Effects pedal, the EP Booster.

We've used the highest quality parts available with a discrete FET design and low impedance output, the EP Booster provides up to +20dB of unadulterated boost with multi-dimensional, shimmering highs and lows, and no ear fatigue. The internal DIP switches let you choose the boost frequencies, and EQ settings.

Update: I noticed I had a cut in between the JFET drain and the 8K2 resistor which shouldn't be there.  If you've already made this then make a solder bridge over that cut and it should work, or if you want to build it use the updated layout below

Xotic EP Booster - Briggs Modded

Requested.  This is a modified version of the Xotic EP Booster, done by Fred Briggs and seen on his blog La Révolution Deux.  Have a look around there and you'll find some really interesting articles and information about many modern and classic effects.  This version includes the voltage converter to provide 18V from a 9V supply.  Cheers Fred.