This is one of the first circuits I ever built due to the simplicity, and it’s hard to go past as a simple boost with a bit of fattening up of the signal.  

The Echoplex EP-3 preamp doesn’t provide tons of gain, but it does work very nicely as a slight boost, or as an always on type effect.   I plan on adapting this to be the front section of a Valve Caster, to provide some extra grit. 

I used the Aion Electronics schematic, as I like the idea of the fat switch, but I did not include the volume control or output buffer.  Pretty easy to add a volume control, I’m sure anyone reading this knows how.  

ECHOPLEX EP-3 PREAMP – POINT TO POINT LAYOUT

version update:  corrected switch wiring.  pin 2 to ground (thanks Solderholic)