Holiday 2012: Guitar Amplifiers

Whether you’re performing in live situations, practicing in your living room or looking for that natural sound for recording original music, an electric guitar amplifier is a must-have item. There are scores of them available. Determine which type you need by reading more below, and whether or not it will help you fulfill your musical goals.

What sort of guitar-amplifier configurations are available?

If you have an electric guitar or synth, and you would like your music to be heard by others in performance, or if you want to amplify your signal in order to mic it for recording or into a music venue’s sound system, then you will likely need a guitar amplifier. (If you are recording directly to a computer, please check out some of these computer audio interfaces.) Amplifiers are available in two primary configurations: the combination, or “combo” amplifier that contains the amplifier head (with requisite electronic circuitry that includes the preamp and a power amplifier) and speaker(s) in a single unit usually made of plywood and covered with some sort of fabric or vinyl; and the amplifier head, or “amp” head, which is a smaller unit that contains the circuitry and connects to a separate speaker cabinet via cables. The amp head is usually designed to sit happily atop a matched speaker cabinet—matched not only for appearance, but also for performance and circuitry compatibility.

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Either configuration will feature one or two ¼” input jacks where you plug in your guitar or synth. Some amplifiers have other input jacks, such as Send and Return, to which you can connect additional effects to create an “effects loop.” Some amplifiers also have outputs that enable you to connect a second amplifier or speaker cabinet so that you can custom craft your tone or create different types of effects. In addition, amplifiers sometimes offer more than one channel, or circuit, so that you can preset a certain tone, effect or volume for each channel. You can have certain settings for rhythm on one channel, for example, and when you want to take a solo you simply activate a second, separate channel with a foot switch. You can then switch back to your original channel for rhythm playing with the same foot switch.

How much power do I need in an amplifier?

An amplifier's output is rated in watts, and the more wattage you have, the louder you will be able to amplify your guitar or synth. Generally, and with exceptions, the most common power range for guitar amplifiers runs from about five watts to an ear-splitting 120 watts, although there are amplifiers that crank out even higher decibel levels (one manufacturer announced a 600-watt tube amplifier head a couple of years ago, outfitted with sixteen 12-inch speakers—they’ll hear your riffs in the next county). This is not to say that you can’t create permanent inner-ear damage with a 15-watt amplifier, because you can. For professional or project studio applications, anything more powerful than 15 watts is likely overkill, and five watts will allow you to achieve cranked-up overdriven tones without rattling the windows or getting your parents or neighbors peeved. You can even find low-wattage amplifiers that feature an attenuator, allowing you to dial down the power of a 15-watt amplifier, for example, by half, to a quiet and comfortable 7.5 watts. If you live in an apartment, this feature could keep you in good stead with your neighbors.

Lower-wattage amplifiers are also great for recording in the same room with other musicians because they can be baffled, thereby reducing the amount of bleed into other live microphones in the room. However, if you are playing with a band in a club, you might want to invest in an amplifier rated at 30, 40 or 50 watts. Also keep in mind that you get what you pay for—higher wattage (combined with other features) will increase the amount on the price tag.

What kinds of guitar amplifiers are there?

There are four basic categories of guitar amplifiers, determined by the nature of their electronics: tube, solid state, hybrid tube/solid state and modeling amplifiers. Each type has its own particular characteristics and sound-shaping qualities.

Tube amplifiers have been around since the inception of guitar amplification. To simplify, the separate power and output elements are driven by vacuum tubes (two common varieties are 12AX7 for preamp conditioning and EL84 for power output, as well as the granddaddy of power output tubes, the long-lived 6L6, which was first patented in 1936!). Tube amplifiers are favored by many rock, blues and country guitar players because tubes produce natural clipping and distortion when an overdriven signal is running through them. Typically, the tone from such amplifiers is characterized as “warm” and “clean” (clean until you overdrive them). Often, tube amplifiers offer certain built-in effects such as reverb or echo (to make you sound as if you’re in a concert hall), tremolo (for that surf-music oscillating effect) and gain (to crank up the signal, clip certain frequencies and create distortion or “dirty” tone). Some of the disadvantages of tube amplifiers are that they are heavy and can be bulky. The tubes are made of glass and naturally, are fragile. The tubes can deteriorate and burn out, and need to be replaced periodically for optimal amplifier performance.

Solid-state amplifiers became more prevalent in the 1970s, when semiconductor circuits were incorporated more and more into the designs of electronic equipment. Unlike the warmth and coloration of sound you would get from a tube amp, a solid state amp produces a cooler, uncolored tone. Solid-state amplifiers can come loaded with effects in a wide range of wattages. For jazz guitarists, this is optimal because they generally prefer not to color the sound of their guitars with the distortion or gain that tube amps create. Jazz players often use arch top guitars with floating neck pickups, and they like to roll off the treble for that “creamy” cool sound (think of the guitar tone of Wes Montgomery, Joe Pass or George Benson). Since tube amps can clip and distort when overdriven, the expanded headroom of solid state amplifiers is beneficial to jazz guitar players because they can crank up the volume when they play with loud instruments such as drums and horns, without distortion.

Hybrid amplifiers consist of an integrated system of tubes and solid-state circuitry. Various manufacturers offer hybrid amplifiers that have solid-state rectifiers and tube outputs (a rectifier converts the AC current entering the amplifier to the DC voltages needed to amplify your instrument). Solid-state rectifiers fit more easily into amplifier circuitry, don’t run as hot as tube rectifiers, and they have a quicker response time than tubes since the voltages are produced very quickly. There are also hybrid amplifiers in which a solid-state preamp feeds tube outputs or a tube pre-amp feeds solid-state outputs. Having a solid-state rectifier or preamp with tube output can give you all the speed and power of a solid-state amplifier with the warmth and natural distortion of a tube amplifier.

Modeling amplifiers use dedicated microprocessors, or chips, to simulate the sounds of classic effects, speaker cabinets and combo amplifiers as well as guitar/amplifier combinations. Some modeling amps have a combination of digital processing and tubes. In addition to the modeled sounds, you can also create a palette of your own sounds with a modeling amplifier, which would be a good reason to invest in one (probably even more of a reason than simply making your inexpensive import guitar sound like a Les Paul played through a stack of Marshall amplifiers). In general, a modeling amplifier simulates a wide range of the sounds of these classic pieces of equipment pretty well but, as always, there is nothing like the genuine article for genuine tone. Modeling amplifiers come in several varieties: solid state, tube or hybrid.

Raising and tilting your amplifier up will help project your signal a slightly longer distance. If you want to get your amplifier up off the floor and throw your sound farther, particularly when you are performing before an audience, there are tilt-back stands made especially for amplifiers that hold and point the amplifier’s speakers at an obtuse angle to the floor.

We hope that this guide has been of help to you, and we’d also be pleased to answer your questions and entertain your remarks in the Comments section that follows. Please contact a B&H Sales Professional with further questions or concerns, via live chat, on the phone at 1-800-606-6969 or in the B&H SuperStore.