Yesterday I was over at Gary Yates' house to practice harp and go over some points from Ronnie Shellist's harp workshop last week. Gary had a little Bugera V5 amp set up and I played it for a few minutes. It was fun!
The tones from the amp are good, and feedback was not a problem. Gary had a small tube preamp hooked up but I preferred the sound when I plugged straight into the amp.
It's a little 5-watt bugger with a 12AX7 preamp, an EL84 power tube, and a solid state rectifier. Controls are gain, tone, volume, and reverb. Fiddling with the gain and volume I was able to get some pleasing harp tone. The digital reverb is usable but a bit too watery.
It also has a power attenuator on the back panel, but this will be a lot more useful for guitar heroes than for harp players. It has settings for full power, 1 watt, or a tenth of a watt.
Interesting feature: It has a headphone out connection; a 1/4 inch jack that would work fine for a line out into a PA system.
The Bugera V5 sells for about $150. It is certainly worthy of consideration if you're looking for a small harp amp and your budget is modest.