I'm too am using a 7 watt amp like Elalto. I got mine from DCkits.com (assembly/soldering required). It works really well - just like Elalto said. Plugging the line input from the Azden into the amp input jack and turning the amp all the way up delivers more volume than the azden alone, with better clarity, and still leaves all the real volume control with the player (MP3). Using a patch cord to plug the ear jack from the Azden into the amp input, and turning up the amp about as high as it will go without starting to "hiss", delivers a lot more volume than the Azden alone, with some sacrifice in qualty (to my ear).
I've got mine setup to where I can use just the Azden to drive the speaker (very light, compact package), or I can use the amplifier and a small 12v gell cell to drive the speaker which gives a bit more volume and longer battery life, but is more heavy and bulky (but still not bad). Pretty slick, I'm liking it enough that I think I'll probably leave my Foxpro home this weekend.
- DAA