The main trick in selecting a guitar power amp is matching the power amp with the speakers. If you are not technical, it may be wise to get some help, but here are some suggestions --
Tips in Selecting a Guitar Power Amp
Your Amplifier's Power Rating -- Find the "IEC Power Rating" for your speakers. Get a power amp that can handle at least twice that. As an example. let's say you have a speaker with a "continuous IEC power rating" which is 250 watts, then you'll want an amplifier that can produce 500 watts. Ensure that both speaker and amplifier are talking about the same ohms. (For the speaker you may see a reference to the nominal impedance of 2, 4, or 8 ohms. For the amplifier it will refer to delivering the 500 watts into a 2, 4, or 8 ohm load.
And a 'Little Extra' -- Headroom. Music (and some other sounds) often contains short-lived ('transient') spikes of sound and that means quick spikes of power. Generally if the speakers are pro-level, they can handle these peaks, even beyond the speaker's official power ... but only if your power amp can deliver these spikes clean. If your power amp is under-powered and delivers these spikes distorted, oopsy! When the power amp has some additional power, or the ability to handle short-bursts of higher signal strength it's called headroom. It's a good thing.
Then there's the "wallet factor" -- but be cautious. Perhaps you already have a power amp and you want to use it with your new speakers. Or perhaps you need to save some money, and you're considering getting a power amp with a little less power, to save the strain on your wallet. Be cautious, and make sure that the amplifier does not begin "clipping." This chopped-off signal can actually damage your new speakers! It's weird, because there's more danger of a power amp with *less* power doing some damage to your speakers. And even if you don't damage speakers, the distorted sound is not really what you want.
Playing Guitar? Or Playing Bass?
A key difference for your amplifier: If you're just starting out on guitar, heck you could do just fine with a 10-watt practice amp, or a small 25-watt combo amp. It will sound just fine for your purpose. But if you're starting out on bass, you're not so lucky. Bass needs much more power, because those long low-pitched strings move slower but wider. When the sound comes from the amp, it moves more air. So you'll just have to bite the bullet and invest in a larger amp when starting out.
Does this mean you need to buy a power-amp and speaker-cab system when just starting out on bass? Maybe not, because there are many good bass combo amps. But here's what it does mean: You are slightly more likely to have to invest in a power amp and speaker cabinets than is a guitarist in the same band. Tough beans, big guy.
Where to Find your Guitar Power Amp at a Super Price?
Online Discount Musician Stores
We've often heard these online stores reported as having great deals --
Your Local Music Store
Big chain stores like Guitar Center sometimes run sales. Be sure you know your amp, and audition it before buying. But remember, many smaller guitar stores, in order to get your business, will match online-discount pricing, and smaller guitar stores can often provide you superior customer service.
Amazon
Sometimes great values, sometimes not, depending upon the seller.
EBay
Frequently the price-value winner, especially if you’re willing to buy used. It’s hard to beat EBay. Just look at this huge selection of best-value power amps and related equipment available right now –
