Adrian Raso (adrianraso.net), Jazzer extraordinaire, takes the Z-28 Mk. II for a spin with an... acoustic!.. guitar.
The EF-86 high fidelity preamp reproduces the sound of his acoustic flawlessly and without coloration, while enhancing the clarity and natural harmonics of the guitar.
http://drzamps.com/product/z-28-mk-ii/