Does my amp have enough juice to power my speakers?


Having just read a review in Stereophile of my Audio Physic Step Plus speakers (which I have to my utter dismay ,knocked over and dinged AAAgh!), the author states that his Shindo Haut-Briton Power amp (20wpc) couldn't drive the Step Plusses and states that nothing less than 35Wpc could drive them.  My dilemma is that I have a Line Magnetic 216 IA rated at 22Wpc that sometimes sounds heavenly and on other days sounds eeh.  Do I need an amp with more boost?  

udog
Do they sound heavenly and eeeh playing the same music?  If so, then it's definitely something else.  If you can find a correlation (demanding source material) then it's probably the amp.
The sensitivity of the speakers is what counts relative to needed power...my 12wpc single ended tube amp through my 99db efficiency speakers will knock yer tattoos off. 
eric has a good point on power quality IF your sound quality varies nite by hite but the SPL and music you are listening to remains constant.

my reference system is bi-amped at 1.2 KW per side, w speakers in the 84 Db class for efficiency, but I never use that ( how do I know ? DMM, SPL meter and an RTA....good tools are cheap, your hearing is not )

I have two other 40 WPC systems that provide adequate SPL for peaks w 86 db class speakers in rooms to 15’ x 35’, of course I dont listen all that loud...certainly no 100 db peaks....

on to your amp, audiogon member contemplating purchase of the 86 db speaker hauled his amp over to my place for 4 hour listening session at levels louder than I normally push - amp held together pretty well and dialed back just a smidge was liquid velvet, its certainly a musical amp. It was running off Isotech power conditioning....

finally for those who dig the high SPL world, get hearing tested....
Back in the day, my father's Brook 10-C3 (Class A to a pair of 2A3 tubes) drove our RCA LC-1A, 15" coaxial speaker to room filling volume. No one asked if they needed another loudspeaker or amp... you were too busy enjoying the MUSIC. I think you have to ask if you are enjoying your MUSIC or not.
you need to provide more data.  I quickly looked up the speakers, 8 ohms, but no sensitivity listed int he review i found. Simple two-way, probably not too bad a reactive load.
I (most of us) don't know much about your amp either. 20wpc is a measurement into a pure 8 ohm resistive load, which is rarely seen in the wild.  Whether an amp can drive speakers depends on many factors including current, stability and simple voltage (generally the limiting factor in FTC power ratings).
bear in mind that dBs are -- and perceived sound levels  -- are exponential and twice the perceived sound level requires TEN TIMES the power - so the next logical jump from 209 is not 35, but 200wpc.
Yet a solid, high current, stable-into-anythign amp will drive most speakers to acceptable levels in a small to medium room.
I would suggest getting all the specs on your amp and calling the manufacturer, or your dealer, if he/she is technical.
84dB, mentioned above is very inefficient and will demand some power to come alive.  That said, i presume you want small speakers for a small living space? Might work fine.

G