I played a godin velocity a few years ago, I really like their HDR ("high definition revoicer"). It was a small push-push button next to the tone knob. What it did it added a small amount of output, and IIRC improved clarity and tightened up the bass. What are they actually? Can I get same effect from aftermarket boost circuit (emg afterburner, artec, etc.) or perhaps some kind of on board buffer ?