Bernie.....had a Fishman under-saddle something years ago on a Martin D16;not much good....quacky sound,etc....haven't much knowledge of electronics,but have had two Martins [OM16 and now an OM35]with LR Baggs I-Beam's...just a stick-on thing on the bridgeplate,a tiny pre-amp in the input cord-jack,and a small volume wheel in the sound-hole...pretty much pure acoustic sound to my ear....preserves the sound and tonality pretty well...there are newer versions on the market which I'm not familiar with...