Does it matter what power amp i get?

Hi I am new to home recording. I have a pair of Alesis M1 Passive speakers and need to get an amplifier for them. I am wondering if (aside from the wattage) the type of the amplifier matters at all? I was looking at an alesis ra 150, its 200 dollars, but a friend told me any old amplifier will work, even a 100Watt one from radioshack (which I couldn't find anyway). But are there any recommendations?
depends it you want decent sound or not...what is your budget? What are the ratings of these speakers (ohms, resistance)?
Of course, practically any amp "will work" and make sound come out.

It is a matter of how much sound quality you want.

There are amps which could cost from $50 to $50,000 and what you are probably looking for is somewhere in the middle. Pick a budget, and look for some good reviews and online comments about amps in the price range, and hopefully using the same speakers as you have(or similar).

Not all amps are created equal, and getting a really good one that matches your speakers well, in your budget, will take a little time and effort to determine.
Oh Ok, I thought the power amp simply powered the speakers, How can it affect sound quality?
Some things about amps definitely matter. You want an amp that can deliver the power your speakers demand. That's a function of their sensitivity and the impedance load they present. Every 100w amp isn't the same, because not every 100w amp can deliver those 100w with low distortion, and because not every 100w amp can handle sudden bursts of power or drops in speaker impedance.

Beyond that, however, amps are fairly similar. The best test is to get an amp into your system and see how it sounds--or, to be more precise, how your system sounds with that amp. Turn the volume up as high as you normally would, and see if you can detect any strain or distortion. If not, then that amp is probably good enough for your needs.
driley, everything up the chain from the speakers affect the sound coming out. Amps, like other components, do have different characteristics from one another. Twl hit the nail on the head when he suggested you take care to match the amp to the speakers. Some amps that sound fine with one speaker will not sound so fine with another (e.g., different damping characteristics or input impedences).

Generally, manufactures match amps to their speakers, so if you are looking at the same brand of amp as are your speakers, you should be OK. Try the Alesis -- if you're happy, go for it. I imagine you should be able to get some kind of money back guarantee you can use if you are unhappy. What the heck -- try a side by side comparison with another amp (also with a good return policy) and see which rocks your boat. Good luck.
Is it to late to trade up to the M1 Actives?
your alesis speakers are a nice sounding little speaker,i owned them for a while & i liked them too.

stay away from the alesis ra-150,its a decent sounding little amp but it lacks balls,you would be alot better off getting an alesis ra-500 for around $350.00 new.

i owned 2 ra-500's & they are a super nice sounding amp & will match perfectly with your m1's.

are you planning on using a mixer for the preamp?

I doubt very much that, in the grand scheme of things, it matters one wit which power amp you get.

As far as the level of your wee existence here is concerned, you may simply take a listen to two different amps of different topologies (a solid state amp vs. a tube amp might yield a good demonstration), with all other components remaining the same to hear for yourself what kind of difference it does make. If that difference is significant to you, pursue the question further and do more auditioning and reading and posting here. If not, you will likely be spared of many hours of neurotic A/B/A comparisons, much speculation and useless banter here on the Gon', as well as being separated from a good portion of your savings and or credit limits.

It does matter but as long as your amp can drive your speakers with ease your pre-amp is more important as it has the larger effect on the over-all of the reasons why passive pre-amps are so in-favor with audiophiles.

If it didn't matter this website wouldn't exist.

Great topic. Aside from reading reviews and doing side by side comparisons, what should one look at on a spec sheet when trying to narrow down such a vast field? I mean - it is really difficult to even get a firsthand look at many of the different brands. So if you find an amp and research the specs on their website, what are the most important things to compare?
Your trying to make it simple. You sure asked the wrong crowd. You don't realize that we argue over Triodes vs Pentodes and whether one $4000 amp blows away another $4000 amp (that have basically the same specifications.)

I will assume you are sincere but are not all that critical and you just want a good performing amp for your speakers. Your search is pretty simple.

1. Find a dealer that has your speakers or something very close to them in cost size, and efficiency.
2. Select some CDs you are very familiar with.
3. Go to the dealer on an off day when the store isn't being overloaded with other customers music.
4. Have the salesman point out the amps that are in your price range and listen to them. Buy the one that sounds best with your speakers and your music. One more piece of advice. Take a woman with you that you respect in terms of "good ears". Women usually have better hearing, they are less swayed by techno hype, and there is usually a significant other who will be pleased you asked. My wife is sensitive to overly bright sounding equipment. I certainly don't want to buy a system that she has to leave the room for me to listen to. (Yes it happens to men all the time.)

I could tell you about impedence matching, TIM, continuous power vs RMS and lots of other items to consider but hay its what the beast sounds like to you that matters.
An amps specs has nothing to do with its sound quality although some mfgrs would like you to believe that. The fact of the matter is that in order for a mfgr to easily achieve those excellent specs, massive doses of negative feedback are applied. The result is an amp with impressive specs but poor or mediocre sound quality. Amps are not all equal and I agree with the above response, the most ideal method of selecting a power amp is to consider your budget & to demo it on your particular speakers. (This is why Audiogon exists). For example your not going to put Krell amp on horn loaded speakers, too bright! Also another important factor in selecting a power amp is to take in consideration the type of music you generally listen to. I think the best part of this hobby is trying different products.