Bass Guitar Tube Amp

Unless you play rock music, tube amps are the way to go when looking for bass tone that offers both clarity and responsiveness.

A tube bass amp’s dynamics respond to its player’s dynamic performance – playing softly will cause it to clean up; playing harder will produce more natural distortion.


If you’re in search of an amp that will stand up to heavy gigging, look no further than a tube amp. These devices utilize vacuum tubes (known as “valves”) to amplify your electric guitar signal and create a rich tone with natural distortion that changes as you increase gain. Their response allows bassists to shape the sound according to dynamic changes in playing style – harder playing will overdrive valves while playing more softly will result in cleaner output from your amp.

Valves respond to your guitar’s input signal in ways no solid-state amplifier can match, giving tube amps their unique musical sound and feel. This characteristic attracts many musicians – from Jimi Hendrix to Pete Townshend – as their signature sound.

Building a tube amp requires many decisions and decisions aren’t made easily or quickly; each method produces its own sound and feel. Selecting the appropriate tube type is also critical; single-ended amp sections sound different than push-pull amplifier sections due to having different harmonic distortion characteristics.

Preamp tubes are the first encounter for guitar pickups and play an essential part in creating the sound and tone of an amp. A 12-AX7 (ECC83 in British parlance), often called triode tubes. Other popular pentode tubes include the EF86 and EL84 which contain four elements each and thus form pentodes.

The next tube that your signal passes through is the power amplifier tube, and this determines the amount of distortion your amp can generate. As more power tube distortion occurs, your amplifier becomes louder and warmer; to control how much of this overdrive occurs you can adjust its bias settings; be wary when doing this however; too hot of a bias could shorten its life dramatically!


Tube amps are beloved devices known for their signature harmonics and fullness of tone. Unfortunately, however, overdrive mode can create harsh and buzzy tones which need to be smoothed out with tone control to avoid harshness or feedback – bass and high-mid knobs play a pivotal role in doing this.

Preamps of tube amps typically incorporate noise filtering circuits to minimize electromagnetic interference and unwanted feedback. This prevents harsh or muddy sounding amplifiers. Furthermore, these noise-filtering circuits help provide dynamic control by matching input signal impedance with that of tubes – the more closely the signal matches impedance is matched to tubes, the less overdrive will occur in response to increased volume levels from overdriving tubes.

At times this can be achieved by placing a resistor + capacitor (Tone Pot) early in the circuit to serve as an RC low pass filter, filtering out high frequencies before they reach gain stages and potentially producing overly bright tones without losing its rich overdrive harmonics that make tube amps so distinctive.

High gain amps tread a delicate line between musical bliss and chaos, and voltage dividers at each preamp stage to throttle guitar signals can help regulate overdrive and distortion levels to the ideal levels for an artist’s desired style. Modifying these circuits to increase or decrease gain or tighten up transition from clean to overdrive mode and add harmonics is possible as well.

Consider that even your “perfect” settings at home may not translate perfectly to other environments – an echoy room may require additional bass and mid frequencies while a loud gig might call for increased treble and presence. Equalisation controls are useful here to customize your amp for each particular environment in which you will play; power tube changes should only be performed by professional techs to optimize its settings further.


Learning the workings of a tube amp will give you greater insight into why its sound differs from that of solid-state amps, as well as make you a more skilled bassist by enabling you to fine-tune its tone for clean and overdrive tones – whether these changes involve simple tweaks such as changing master volume settings or more complex ones such as adding negative feedback loops.

An electric guitar tube amplifier derives its sound from electrons circulating between power and preamp tubes, as illustrated in this simplified schematic. A guitar signal pulls electrons from ground via a bypass capacitor to an EL84 preamp tube (in this instance) then through an output transformer back to ground again via another bypass capacitor before they continue their journey via another preamp tube called an EF86 that then passes them on through yet another bypass cap and finally to a speaker via another bypass cap.

These tube circuits can be altered in various ways to give each amplifier its individual sound. The type of power tubes used has a major influence on its tone as do secondary harmonics that result from it; an EL34 tube, for instance, creates entirely different harmonic overtones from those produced by 6L6GC tubes.

Bias of power tubes is another key consideration. Biased tubes should produce higher current at their cathodes than their plates for smoother distortion and reduced harshness of distortion; conversely an over-biased tube can result in hot peaks or excessive voltage sag that significantly shorten its life span.

Choice of tube amp can depend on its effects; use of reverb or chorus effects is especially key, while selecting an excellent speaker should also be taken into consideration. Ensuring sufficient heat levels and using an impedance load that matches speaker impedance should also be top priorities to prevent damage to tubes and components; moving around while it’s on is particularly detrimental as this can shock it, potentially leading to instantaneous failure of filaments and other parts within a tube amplifier; finally don’t touch anything in a running amp as this could burn your fingers!


Bass guitar accessories can add an elegant and enjoyable element to any setup, including pedals that help shape tone, as well as amplifiers that provide enough power for gigs. Your choice of accessories depends on your musical style and type of bass you play; some bassists prefer clean tones while others favor distortion sounds. Choosing appropriate preamp tubes and speakers can improve performance of amp, while upgrading tubes can increase headroom or brighten tone quality further. Additional controls like drive, compression or sub can alter how other controls respond and give your sound an additional flavor – giving your sound an extra depth that gives your sound an extra flair!

Your bass guitar tube amp should offer additional features to enhance the experience of playing bass. These may include digital displays that show you the status of your amp, as well as remote controls that let you access different presets – perfect for beginners wanting to start learning the instrument at home as well as live performances.

One of the most coveted bass guitar accessories is a compression pedal. This pedal adds subtle distortion to your signal while also helping boost low frequencies or smooth out high frequencies. A bass guitar tube amp may work, though be aware that its effect will change with increased volume levels.

When shopping for a bass guitar tube amp with more features, look for one with a dedicated bass channel and EQ settings – this will allow for more accurate and balanced sound quality. Furthermore, consider amps with built-in digital reverb and distortion effects, or amps equipped with compressors that help reduce dynamic range in your music.

Beginners should consider purchasing a basic model. These guitars tend to be lighter and cheaper than their tube counterparts while still offering plenty of tones and effects for practice purposes – and will work perfectly with most basses.