Ever since solid-state amplifiers emerged in the 1960s, the debate has raged over which type of amplifier is better for bass. There has been what amounts to a “tube amps vs solid-state amps” war that has been waged in music stores, online, and between otherwise good musical friends.
For us bass players, the choice isn’t quite as volatile as it is for guitar players, many of whom would rather drink poison than play through a solid-state amp. Still, there are those bassists that swear by that natural, warm, fat tone that a tube amp delivers.
So the question is, what’s the difference between these amps, and what’s best for you? Oh yeah…and there’s also a third option.
How does a tube amp work?
The vacuum tube amplifier, or valve amp as it’s sometimes called, was for many years the only way an amp was powered. At its most basic, it’s simply a piece of audio gear. It takes a signal and increases its amplitude using vacuum tubes, or valves. They’re also sometimes called power tubes.
The alternative would be a transistor amp, but we’ll get to that in a bit.
Amplitude is normally measured from peak-to-peak, as waves. The amount of change between the highest part of a wave, the peak, and the lowest part of a wave, the trough, is your amplitude. This is the aspect of a signal that the amplifier increases.
Tube amps use a “push-pull” system, also called a class AB output section (if you care). The system splits the audio signal and then rejoins them at the output transformer. This provides greater efficiency and longer life for your equipment. It also contributes to the amp’s unique tone.
On a very basic scientific level, vacuum tubes are used to provide an environment to control the flow of electrons. When heat is added, the components are even better suited for these purposes.
Tube amp history
Amplifiers based on vacuum tubes were introduced in the early part of the 1900s. They dominated the market up through the 1970s. When transistors became popular due to their lower cost, lighter weight, and higher reliability, tube amps saw a huge decline and the solid-state amplifier took over as the favorite choice for most bass players.
The 1980s in particular saw an enormous increase in solid-state bass amplification. This was the case until the early 1990s when grunge emerged and the shift back to all things vintage started.
Virtually every style of music employed tube amps prior to the 1970s, from Jazz and Rock to Pop and Funk. The warm fuzz of ’60s psychedelic rock and the fat bass tones of ’70s funk is an unmistakable product of those circuits.
Why do we still use tube amps?
Most musicians and studio technicians who use tube amplifiers do so because they love the warm, natural sound that they produce as opposed to solid-state circuits, which can sound artificial or sterile to some.
The natural overdrive of power amp tubes is highly sought after even today. The amp designs and the way valves function, in general, helps to avoid that harsh tone that transistor-based amps can have. They will, generally, also sound louder than solid-state amps at the same volume.
Although technically solid-state circuits have higher fidelity than tube circuits, lovers of amps with tubes swear that there is a huge difference in the quality of the sound produced by all-tube equipment. For them, the benefit of tubes far outweighs the cons.
Advantages of tube amplification
The tone that they produce is, by far, the main benefit. Some argue that this benefit in sound is the only real advantage. However, it’s obviously an important one when it comes to music. Oh, and there’s also that really cool glow you get from a warm valve.
A tube amp will almost always have more pleasing harmonic overtones than a solid-state amp due to its smoother transition into clipping ranges (overdrive). It’s almost cliche now to talk about that “warmer sound” you get from tubes. But, there’s some actual science, as we’ve seen, to back that up.
The overdriven sound of warm amplifier tubes is highly valued by rock players, jazz players, and musicians from nearly every musical genre. You can get some incredible sounds from these amps whether you’re looking for a distorted sound or not.
Tube amp drawbacks
Tube amps are generally much heavier, much less reliable, and much more expensive than their solid-state counterparts. It’s much easier to blow tube equipment, and they tend to get very hot.
Companies that produce new guitar amp tubes are often found in Asia and Eastern Europe, and production standards might be lower in those factories. Since a glass tube can vary in its construction, there is often a real sound difference between tubes.
This last point may be a benefit for some people who enjoy some randomness in their sound as something more natural to work with. Then there are others who will search everywhere and pay heavily for new old stock American and British tubes.
Enter solid-state amps
The solid-state amplifier has been around since the 1960s. They’re called solid-state because the electricity moves through solid material rather than a vacuum. These amps use transistors to amplify signals.
In the early days, the new transistor amplifiers were much maligned among bass players. The main problem was that, unlike tube-powered amps, a solid-state amp will cut off a signal at its peak rather than pull it back like a tube amp will. This created an unpleasant distortion and somewhat dry, sterile sound.
In recent years, however, the solid-state amp has become much more musical sounding due to newer technology and a better understanding of how to replicate tube circuits within a solid-state design.
Benefits of solid-state amps
Using solid-state amps is much less controversial in the bass community than it is within the guitar world. With bass players, the choice is more about the sound they’re after rather than the actual quality of the signal. Many bassists prefer the uncolored, clean tone of the solid-state sound, not to mention the greater power and lighter weight.
The reality is that solid-state amps are here to stay and are getting better every year. While some bassists will always prefer the tube amp sound, the solid-state amp is still king in the marketplace.
Solid-state amplifiers are lighter and generally less expensive than tube amps. They are also much more reliable and require very little maintenance. A solid-state amp can produce far more output (watts) than a tube amp of similar size.
They also offer faster transient response times and a transparent, clean sound favored by some bassists and producers. Many solid-state amps have more options for modifying guitar tones, especially on the higher-end models.
Solid-state amp drawbacks
If you’re after that warm, old-school tone, a solid-state amp just won’t do. While there are many convincing solid-state tube simulators on the market, for many bassists nothing can replace the warmth and pleasing natural distortion of a real tube amp. Amps built on solid-state technology will almost always have a more brittle sound at the top end of the output range.
Transistor circuits will clip more abruptly than tubes, which can sound harsh to the ears. Even amps with very high end transistor technology won’t give you that soft, warm compression and overdrive that only vacuum tube technology can produce.
One note about this abrupt clipping though. Some guitarists really prefer the biting guitar sounds that they can get from transistors. This aggressive sound works really well for genres like early metal and punk.
In the last decade or so, there has been another amp option, the hybrid amp. It’s basically an audio device that uses both transistors and vacuum tubes to amplify a signal. Hybrid bass amps have become extremely popular in recent years mainly because they combine solid-state reliability with that warm tube sound.
Most hybrid bass amps use a solid-state power amp stage in combination with preamp tubes feeding it. This design allows for more power without the need for an output transformer like in a classic all-tube-powered amp.
Essentially, the solid-state power section does the heavy lifting, dramatically boosting the signal and driving the speaker. The pre-amp section usually contains only one or two tubes (some have more) that basically color the tone of the signal, giving more warmth and flavor to the sound.
Hybrid amps vs all-tube amps
Most hybrid amps will never sound as warm and fat as an all-tube amp. However, the hybrid is the perfect compromise for those bass players who want a classic sound without all the heavy lifting and maintenance that comes with an all-tube amplifier. Hybrids usually cost less and are easier to maintain as well.
For most situations, a hybrid amp will work well because by using the settings you can achieve either a clean solid-state sound or a warm tube sound. This is especially useful to bass players that play many different styles and need as many tone options in their amp as possible.
Hybrid amps vs solid-state amps
Hybrid amps tend to be more expensive than solid-state amps of the same power rating. Because hybrid amps have pre-amp tubes, they will require more maintenance than solid-state amps and will also be more likely to break down. Hybrid amps are usually a little heavier than solid-state amps of similar size due to the extra components as well.
The bottom line is that you have to choose what’s right for you, and not just because your favorite bass player uses a particular amp. In fact, many bassists have both types of amps for different situations. I personally prefer the all-tube amp sound but usually play through a solid-state amp for convenience.
Then there’s also a fourth option, the digital amplifier…but that’s for another post.