An amplifier head for bass guitar serves to send output signals to a speaker cabinet. Sometimes this component and cabinet come combined together as one single unit known as a combo amp.
Some bass amplifier heads feature built-in overdrive effects; for instance, Marshall 100 watt bass amp models named after Lemmy Kilmister have overdrive effects that range from gentle warmth to severe distortion.
Power
A bass amp head provides power to drive speaker cabinets. Each model has an impedance rating which indicates how much power it can deliver to connected cabinets; for instance, one capable of producing 300 watts at 4 ohms should only be connected to 4 ohm cabinets (see our bass cabinet guide for more info). Plugging an 8-ohm cabinet into an amplifier producing 400 watts will lead to overworked speakers resulting in unpleasant sounds or possible fire.
An amp head is also an essential component of a combo amp or bass stack, where multiple amplifier heads are stacked one atop another with a cabinet attached below them. This arrangement enables bassists to tailor their setup with various preamps and effects for various sounds and applications as well as switch between various cabs as needed; plus the amp head itself can easily be disassembled from its cabinet for easier transportation and assembly during gigs.
In the 1960s, rock bassists such as John Entwistle began using powerful bass amps with multiple speaker cabinets to play loud enough music for large venues. This trend led to stacks — which consisted of amp heads mounted atop multiple speaker cabinets — becoming popular. Thanks to modern digital modeling technology however, there is now an affordable selection of bass amp heads which offer you both tone and volume without incurring additional expenses.
Many of these models feature a built-in preamp and various knobs to tailor sound parameters, including EQ, drive and chorus settings. Some even come equipped with built-in reverb and chorus. Others can even be used with external pedals for increased distortion and gain.
Some bass amps provide additional features that enable bassists to easily muffle the unit for tuning or instrument swapping, and an input jack for connecting a DI box for direct recording onto a computer. Some also feature VU meters that display output level in real time while other models have LED indicators for conditions such as clipping.
Impedance
Impedance of your bass amp head should be carefully considered. Impedance refers to how much resistance (measured in ohms) is present when connecting an amplifier’s output to a speaker cabinet, and is calculated based on how much electricity flows out instead. An amplifier should match up with this load.
Impedance plays an important role in how much power an amplifier delivers to speaker cabinets; lower impedance cabinets will enable more from their amplifier, while high impedance ones may require more of their output to drive them; this may cause distortion, so for optimal performance it is wise to have equal impedance between amp and cabinet.
Most amps use tubes that require airflow for proper cooling, along with large transformers to supply current to them and send it directly into their tubes. As a result, these amps tend to be quite heavy – an average 50W tube amp can weigh in excess of 50 pounds!
Modern transistorized amps feature smaller housings and are usually lighter. Furthermore, they’re less costly as they don’t rely on massive transformers like their tube counterparts do for functioning properly.
Bass amps are built to convert small electrical signals into larger ones that can drive speakers at levels sufficient to make drummers cringe, with preamp sections offering various tonal-shaping options that enable bassists to create their own distinct sounds.
When purchasing a bass guitar amp head, Sweetwater provides filters to help narrow down your selection and focus on specific brands, specifications, styles and price points that matter to you most. Our filters allow users to tailor their search based on brand, desired specs, styles and price points that matter most to them.
Always use speaker cables when connecting your bass head to a speaker cabinet. Although instrument cables may appear similar, their thinner gauge could lead to damage if drawn too much power from them – we suggest opting for at least 18- or 16-gauge cable to safeguard your rig from potential harm.
Portability
If you’re playing smaller venues or trying to reduce back strain while transporting a bass amp and speaker cabinet around town, a compact head and cabinet setup is an ideal solution. Bassists have plenty of choices available when creating such an arrangement: high-powered heads paired with two 15″ cabinets (for larger halls or arenas) or powerful single 1×15″ cabinets (which work great for clubs).
To achieve maximum portability, seek out bass amp heads that employ Class D technology. This innovation allows builders to pack more wattage into smaller chassis without compromising tone quality – not to mention today’s small bass amplifier heads are more affordable than ever, making them suitable for various budgets.
Trace Elliot ELF stands out as an exceptional portable bass amp that weighs less than a laptop computer and packs 200 watts into an amazing 6.75-in x 2.75-in package – making it one of the most portable amps on the market! Featuring two channels with 3-band EQs, channel select push buttons, Voice and Effects volume knobs as well as SpeakON output for connecting directly to speaker cabinets; Direct Line output; tuner output and headphone jack. Plus its beautiful Sunburst finish that pays tribute to its designer from Britain!
While tube amplifiers remain an option in modern bass music, many modern bassists are turning towards solid state amplifiers for convenience and portability. These amps use MOSFET transistors to amplify input signals, and feature many of the same controls found on tube amps – plus their lack of moving parts means they’re more affordable and durable!
Finding a small, powerful, and portable bass amp head may seem like an impossible feat; but Sweetwater makes the task simpler by offering various filters to narrow your search down by your preferred brands, specs, styles and price range. You can even filter by whether or not you would prefer a combo model or head and cabinet(s). With such wide-ranging choices available to you, finding your dream amp has never been simpler!
Tone
Bass amp heads are essential parts of live performances on lower-pitched musical instruments like bass guitars. They convert smaller audio signals to larger ones which power speaker cones; many also come equipped with features to modify tone or alter tone entirely.
Your choice of bass amp head depends on what sound and power output you’re after, with many bassists opting for solid-state amps using transistor technology instead of delicate valve circuitry – these tend to be smaller, lighter and more reliable, yet may not produce the same tone as tube amps – however many modern solid state amplifiers utilize circuitry that emulates their warmth making them suitable for gigging bassists who don’t want the added cost and hassle of replacing tubes regularly.
Tube bass amps remain popular due to their unique sound and power. Many bassists appreciate how tube circuitry sounds when put into overdrive, producing subtle to heavy distortion effects that range from subtle to heavy distortion levels. While this distortion may be desirable for certain situations, care must be taken when using gain/volume controls to avoid clipping which could ultimately harm the quality of sound outputted from these amplifiers.
Modern musicians have access to an assortment of bass amp heads for all situations and budgets – from lightweight Aguilar Tone Hammer 500 models, which offer great portability, to powerful models like Phil Jones Bass D-1000 that put out 1,000W from its four pound frame and can fit easily into an accessory pouch in most gig bags.
Most bass amp heads provide at least one input jack, gain and volume controls and typically feature a three-band equalizer with bass, middle, treble controls. Some amps even offer parametric or graphic equalization options that let users adjust their tone based on playing venue or music style preferences.
Mini-stacks offer bassists on a budget an economical solution that combines low-powered amp heads with matching speaker cabinets; Ampeg’s popular PF-50T Portaflex stack, for instance, pairs its 500W head with its matching cabinet to produce impressive lows. Some bassists opt for building their own custom rig using separate amp heads and speaker cabinets instead, making component replacement more accessible if worn-out preamps, graphic EQs or power amps need to be changed without purchasing an entire new amplifier.