I've been playing through a Pignose for years.  The Legendary 7-100 has been around for decades and is perfect for the harmonica.  This amp is small weighing in at only 5lbs.  It's loud with a 5 inch speaker and 5 watts of power this amp can really wail...and it's portable holding 6 AA batteries you can take the 7-100 anywhere.

There are 3 different models the traditional with a rugged covering, Snakeskin, and a Special Edition Tweed (my personal favorite)...these amps look awesome.  When playing with a bullet mic the tiny speaker gives an awesome overdriven rumble when the volume is turned high.

The Legendary 7-100 will give you awesome tones that range from clean to dirty little piggy...use it for practice, as a pre amp, in the studio...take it to the streets or the arenas...because this little piggy went to the market and came back with the blues.

Seriously though.  I use the Pignose over other amps for a lot of reasons (other than the sound).

1.  Portability - I play harmonica.  I keep them in a small case and like the fact that I can travel light.  Large amps are heavy...but the Pignose is only 5lbs and is small enough to carry easily.  Many times I keep mine in a gear bag with cables and mics.

2.  Battery powered - No power cords needed, just AA batteries.  You can get an adaptor...but with batteries you can take it anywhere.  Camping, back porch, and street harmonica playing are easily achieved...and that leads into point #3.

3.  Guitar strap hangers - Those neat little knobs on the side are set up to be used with a normal guitar strap.  Ever seen Crossroads?  Ralph Macchio carries his Pignose on a strap...and they are still designed the same way today.

There are a lot of famous amplifiers out there.  Big.  Powerful.  Loud.  Amps that have been played in arenas, dives, and cruise ships...but the Pignose is Legendary because it's been played by some of the biggest names in the business...and is so affordable that almost anyone can buy one.  Here's a few clips where the Pignose was used.