So ya wanna buy an amp. You just got your student loan, and your new band finally has a gig in a week. Your friend wants the amp you've been borrowing from him for the last two years back. You're ready to take the trek to the local music shop, but know nothing about amps. Here's a rough guide as to what to look for.

Guitar or Bass
Guitar amps tend to be less powerful than bass amps. They are often smaller, and contain 10" or 12" speakers. They often have reverb and distortion effects built in. Bass amps tend to contain larger 15" speakers (these give more bass), 10" speakers (more punch), or an assortment of both. Either can usually be used with keyboards, but bass amps tend to handle them better.

Wattage
Wattage is how much power an amp has. The higher the wattage, the louder it gets before it starts distorting and crapping out. Distortion, fuzz and overdrive are all terms for when an amp starts running out of juice. This used to be an undesirable effect, but sometime in the early `60s, it became stylish and exciting. Now it has defined the sound of the electric guitar. Loud volume levels used to be required for good distortion. Now most amps have it built in, allowing for low volume distortion, or you can just buy a cheap distortion pedal. For live purposes, guitarists will usually require at least 30-50 watts in an amp. Bass players usually require cleaner tones, so you should start at 50 watts bare minimum. A cool home practice amp could be five watts or less. They'll distort and sound cool at very low volumes.

Tube vs. Solid State vs. Hybrid vs. Digital Emulation
Up until the late `60s, most amps were tube amps. Tubes (or "valves" for the Brits) are those things in old radios that sort of look like light bulbs. They glow when you turn the amp on. Most people find that tube amps sound warmer and more appealing. They naturally distort in a good way at high volumes. However, they tend to be a bit more expensive and require a bit more maintenance. All the classic brand names like Marshall, Fender, Hiwatt, Vox and Ampeg made their names with their original tube amps.

Solid state amps use little black thingies called transistors. Many people find that solid state amps (or transistor amps) tend to sound colder. But some have become classics, such as the Roland Jazz Chorus, the Kustom amps (Will Kidman of the Constantines played one for a while), and the Acoustic brand (Death From Above). All of Nirvana's Nevermind was recorded with a solid state Fender and a Boss DS-1 Distortion pedal. So don't knock `em till you try `em.

Hybrids are a newer development that mixes tubes and solid state design. This allows for a compromise that give you tube sound and solid state price. Marshall has developed a great sounding series of this type titled Valvestate (Mr. Dovercourt of Republic of Safety himself plays one).

Digital Emulation amps are a newer trend that uses strange binary computing microchippy stuff, like in the movie TRON, to make amps sound like other amps. I don't really know anything about any of it. Their price range is in the same ballpark as a new car. They tend to have lots of blinky lights. Fender, Line 6 (Sammy Goldberg of Uncut), Peavey and Vox have all released D.E. amps to varying degrees of success.

Stack vs Combo
A stack is an amp that has the amplifier (the Head) separate from (and stacked on) the speakers (the Cabinet). When you see old photos of Hendrix and The Who playing, they'll have walls of cabinets, with the heads on top. They are rarely less than 50 watts. They tend to be easier to lug around in two pieces. You can mismatch heads and cabinets to suit your own sound and budget, however make sure your impedances are matched (consult your U of T Electrical Engineering Textbook, it's too much math for this publication). A combo is the classic smaller amp with the amp and speaker in one box. They tend to be more compact, but can occasionally be deceivingly heavy.

The Purchase
So you've got your budget, and you know what you need. Now you need to test drive. It's a good idea to bring your instrument and a bandmate with you when trying new amps. Some amps sound great with certain guitars, and awful with others. Ask to crank the amp to stage volume to make sure it'll cut it. Ask lots of questions. Salesman love showing off their nerdly knowledge.

And uh... try to be real nice to the guy that's working the shop that day. Rock. Repeat.