Bass guitar amplifier heads provide power to speaker cabinets, although some gigging bassists opt for smaller amps with no cabinet at all for greater convenience, or can run their bass directly from their amplifier for pure tones.
An amplifier’s resistance, or “ohmage rating”, must match that of your cabinet (for example a 16 ohm head in an 8 ohm cabinet). A higher resistance rating allows an amp to handle more current.
Power
This solid-state amp head offers powerful performance for bassists looking for serious power. Boasting 200W RMS of output power, it can handle virtually all situations on stage without sounding dull – yet its controls remain user-friendly even under dim stage lighting conditions.
An amplifier head is a component that transfers low voltage audio signals to a speaker cabinet, which then transforms them into larger voltage signals that drive its cones. While most bass amplifiers combine preamp and power amp into one unit known as a combo amp, some bassists prefer separate amplifier heads linked with multiple speaker cabinets (or cabinets).
Heads connect to cabinets using speaker cables equipped with 1/4″ jack connections. These thicker cable thicknesses differ from instrument cable thickness, typically being measured in gauge size with higher numbers indicating thicker wires. You can match an amp head to its cabinet according to impedance rating (either 4, 8 or 16 ohms); most amps fall into these categories.
Some bassists opt for hybrid amps that combine a tube preamp with a solid state power amp. Tube enthusiasts argue that tube preamps offer warmer sound when pushed hard to the point of distortion; on the other hand, some bassists like harsher tones from solid state preamps when driven hard. It all boils down to personal preference and what style of music you play – this combo bass amp provides all of these features without busting the bank!
Impedance
Impedance refers to the resistance of your cabinet’s speakers when wired together parallel or series. If you use a speaker cabinet with an impedance that falls below the minimum rating for your amplifier’s head (this information can be found on its back panel), you risk damaging its output transformer as well as hearing artifacts caused by mismatch in frequency response that generally affect lower frequencies and can be unpleasant to listen to.
Most bass guitar amplifiers are designed to handle 4 or 8 ohms of resistance. To maximize the performance of your amp head, choose a speaker cabinet with an ohm rating equal or slightly greater than its minimum ohmage value – this will prevent damaging your amplifier head while still enabling maximum power delivery to your speakers.
Ohm ratings of speaker cabinets vary significantly, even among similar cabinet models, depending on wiring configurations and speaker placement within them. Factors such as number and size/type (alnico, ceramic or neodymium), wood type used and other variables can have dramatic impacts on sound.
Professional-grade bass amplifier heads often include an audio crossover, which divides the bass signal into low and high pitched frequencies and sends each one to different speaker cabinets suited for those frequencies. This feature can help fine-tune an amplifier’s sound to meet the requirements of various venues or styles of music, and may come pre-set by the factory, or equipped with an adjustment knob so the bassist can adjust his/her own crossover point as necessary.
Volume
Bass amp heads typically offer various controls for customizing their initial gain and tonal shaping, including volume, master tone and gain knobs and bass boost switches to increase overall output. Many also come equipped with reverb or delay controls that can create more expansive tones.
One can find many different bass amp heads available today, from practice and studio amps to high-powered rockstar rigs. Many are designed for easy transport from rehearsals to performances or venues with features like carrying handles or wheels on larger combo amps; additionally protective coverings may be provided to protect both cabinets and speakers, with rackmount versions also being made available to professional performers or players who require multiple amps at one time.
Most bass amps feature 1/4 input jacks for connecting speaker cabinets or powered subwoofers, as well as send and return jacks for creating an effects loop. Some models also come equipped with tuner out jacks and auxilary left and right inputs. Many amps will also offer an attenuator knob which reduces how much power is being sent out by their amplifier; this enables it to be increased without overdriving speakers.
General, it’s recommended to match the impedance between head and speaker cabinet as closely as possible (i.e. an 8 ohm head into an 8 ohm speaker cabinet), though mismatching may still be possible depending on how well your amp was designed. When mismatched, however, mismatched speakers may not be able to handle as much power as intended and cause overheating or circuit damage within your amp.
Tone
Bassists want their amplifiers to have an enticing tone. To accomplish this, the bassist will adjust the EQ controls. Here is where the sound of their amp truly comes to life; by altering these parameters they can make their amplifier sound deep or light depending on their preferences; many bass amplifiers include controls for low frequencies, mid frequencies and treble frequencies on most bass amps.
Nearly all bass amplifiers feature a gain control, also known as drive. Gain adds power to the signal while responding to player dynamics: as one plays harder, more signals break up, providing gritty tones. Lowering gain results in an amplifier that sounds less powerful and distorted.
Some bass amps feature a graphic equalizer, with vertical sliders providing control over various frequency bands. For instance, turning up low-mid volume to increase thickness while turning down high-mid frequency can reduce shrillness or clarity in sound output.
Many modern bass amps feature a hybrid design, which incorporates both tube preamplifier and solid-state power amplifier components into one amplifier. This style can provide the tube-style warmth desired by some bassists at lower costs and smaller packages; giving bassists another option when traveling light or when space is an issue.
A bassist may opt for a fully solid-state amplifier head such as the Mesa Boogie Subway D-800 or Aguilar Tone Hammer 500 to produce powerful arena-filling sound without taking up too much room in his or her gig bag’s accessory pouch. Solid-state amps tend to be more efficient than tube ones and produce distortion at a lower volume level, making them suitable for stage use.
Effects
A bass amp head is an electronic device that uses electrical power to make lower-pitched instruments such as the double bass loud enough for audiences and performers to hear. The amplifier typically includes preamplifier, tone controls and power amp that drive one or more speakers (transducers) in a cabinet; most modern bass amps use solid state transistor amplifier circuitry.
Most bass amps also provide a speaker output connection on their back panel to enable users to connect a separate speaker cabinet. The cabinet serves as an active speaker designed to receive signals from an amp head, and may vary in size and construction with different types of loudspeaker cones (made of materials such as alnico, ceramic or neodymium), wood finishes and mounting options for easy placement.
Depending on the type of amp, bass amp heads may feature additional features like an effects loop (to feed external pedals and effects units), “send/return” jacks for creating effects chains, left and right inputs for use as auxiliaries, tuner output and master volume controls; some modern bass amplifier heads even boast built-in digital effects like chorusing delay or reverb effects.
Certain bass amps, such as the Ampeg SVT 400-PRO (shown), feature an audio crossover which splits the bass signal into low frequency signals for cabinets suited for this register and high frequency signals that are better suited to higher pitched frequencies.
As much as it is recommended to match amp head & cab impedance, most bassists do not comply. Doing so would reduce available power for speaker(s). However, this practice can still be considered safe provided that an amp’s maximum output wattage does not surpass that of its cab’s total ohmage rating as per Eminence website recommendations.