Guitar 101: What Is a Solid-State Amplifier? Pros and Cons of Solid-State Amplifiers and the Best Solid-State Amp for Guitar Players

A solid-state amplifier uses transistor circuits to convert an electrical signal into an audio wave. Instrumental amps contain two stages of amplification: the preamp stage at the beginning of the circuit, and the power amp stage at the end. In between these two stages of amplification, the sound may be shaped by effects such as EQ, reverb, vibrato, and tremolo.

The physical difference between a solid-state amp and a tube amp is that a solid-state machine derives amplification from electronic transistors, while a tube amp uses vacuum tubes (also known as valves). Transistors operate differently from tubes in the sense that they don’t pleasantly distort when pushed to their limit. By contrast, most players will tell you a tube amp sounds its very best when pushed to the max.

Here are some other key differences between tube and solid-state amps.

• Solid-state amps are great for players who want maximum headroom (a.k.a a loud, clean, undistorted signal). But without a bit of natural distortion, an electric guitar can sound a bit brittle. As such, solid-state amps are more popular with bassist and keyboard players than with guitarists.
• This isn’t to say that guitarists completely eschew solid-state amps. Jazz players, many of whom play with almost no overdrive at all, tend to favor solid-state amps. This is partly for tonal reasons, but it’s also because solid-state amps are almost always lighter than tube amps, and many gigging musicians value the convenience of a light amp.
• Rock musicians also use solid-state amps. Andy Summers of The Police is famous for his use of the Roland JC-120 Jazz Chorus amp, which is unapologetically solid-state (and incredibly loud). John Fogerty’s guitar leads on Creedence Clearwater Revival records were achieved with a Kustom solid-state amp. Meanwhile, Radiohead’s Jonny Greenwood tends to use tube amplifiers for clean tones and a solid-state Fender Eighty-Five for distorted tones— the opposite of what most players would do.

Solid-state amplifiers contain multiple advantages over tube amplifiers, but not all of them are related to audio quality.

• They are cheaper. Almost all solid-state amps are cheaper than their tube counterparts. They contain fewer parts, and the parts they do contain are relatively inexpensive. This contributes to lower prices across the board.
• They are lighter. If you are a gigging musician and need to haul an amp all over town, weight can play a big factor. Tube amps almost always weigh more than solid-state amps. This isn’t on account of the glass tubes themselves—they’re hollow—but rather the circuitry required to operate them.
• They require less maintenance. Tube amps require regular upkeep. Most gigging guitarists will change their power tubes about once a year and their preamp tubes about every two years. By contrast, solid-state amps don’t require the swapping of parts. They can continue functioning with all their original components for decades.
• They are less fragile. Guitar amp tubes are made of glass. If you drop your amp and the glass happens to smash, you’re out of luck. The amp will not work without its tubes, and you’ll have to replace them before your next performance.

Solid-state amplifiers are cheaper, lighter, and easier to maintain than tube amplifiers. So why doesn’t every guitar player use one? The main reason is that most players don’t think they sound as good.

• Solid-state amps are not versatile. Tubes produce distortion when they operate. This can be a very mellow, sweet distortion that’s often described as “warm.” (Tube amplifiers on home stereos have this same effect.) That warmth is desirable on a lot of instruments, particularly treble-focused ones like an electric guitar. By its nature, a tube amp will mitigate some of a guitar’s piercing high frequencies, while adding the desired coloration to all its frequencies across the board. Solid-state amps can’t do this. Their pure crystalline sound can be great for some instruments, but it isn’t right for everything.
• Solid-state cannot cope with heavy amp distortion effects. Some guitarists also use their amplifiers to get heavy overdriven sounds. Think of Jimi Page’s wailing guitar tone on the “Stairway to Heaven” solo. Or think of the propulsive thrash of Metallica’s “Fight Fire With Fire.” Those sounds were produced by amplifiers, not pedals or other effects. And they can only be produced by tube amps; a solid-state won’t come close. So for heavy amp distortion, it’s pretty much tube or bust.

Solid-state amps are most popular among bassists and keyboardists. Bassists don’t have to worry about piercing high tones and they rarely seek out distortion. Therefore, the advantages of tube amplification didn’t apply to them as much, and over the course of the 1960s and 1970s, many electric bassists switched to solid-state amps.

Here is a list of the most well-regarded solid-state bass amps:

• Markbass CMD series
• Gallien-Krueger MB112 combo amp
• Ampeg SVT-7PRO Head
• Aguilar AG 700
• Fender Rumble 40 and Rumble 500 (lower-priced options)
• Peavey Max 115 (another budget-friendly option)

Keyboard players are also frequent users of solid-state amps.

• The electronic keyboard contains a massive array of pitches, and many players feel that a solid-state amp does a better job projecting a broad span of frequencies when compared to a tube amp.
• Like bassists, keyboard players are less likely to use a distorted sound. The crystalline clarity of a solid-state amp might be perfect for their needs.

Gigging guitarists may also appreciate a small solid-state amp that they can easily carry by hand or bring on a cart.

• The Fender Eighty-Five (with red knobs) is a good option.
• Marshall also makes a decent solid-state amp, which is called the Valvestate.
• Peavey, Randall, Line 6, and Blackstar also make good solid-state amplifiers.

For guitarists determined to use a large solid-state amp, there is one model that rises above the competition: the Roland JC-120 Jazz Chorus. These amplifiers were massively popular in the late 1970s and ’80s rock scene, with famous practitioners including Andy Summers of The Police, Robert Smith of The Cure, and Steve Hackett of Genesis. Here is why:

• The JC-120 features a modulation effect that alters the pitches you play on your instrument. In one setting, this works as a chorus effect: it creates the illusion of multiple instruments all playing the same line together. In the other setting, it works as a vibrato effect—toggling your pitch back and forth with another pitch that’s close to it.
• The JC-120 is still favored by some guitarists today. It isn’t small, but it’s lighter than its tube counterparts. And it contains some of the greatest amounts of headroom of any amp—which is to say it can get very loud without distorting. It can still be a bit brash on higher frequencies, but with a bit of EQ-ing, you can mellow out its sound. As a general rule, it remains the best regarded solid-state guitar amp on the market.

Curious about amps? Learn what gear Rage Against the Machine’s Tom Morello uses in his MasterClass.