page_title: Instrument amplifier
section_title: Tube amplifiers
hierarchical_section_title: Instrument amplifier / Amplifier technology / Tube amplifiers
caption_attribution_description: Trace Elliot Bonneville rear view
context_page_description: An instrument amplifier is an electronic device that converts the often barely audible or purely electronic signal of a musical instrument into a larger electronic signal to feed to a loudspeaker. An instrument amplifier is used with musical instruments such as an electric guitar, an electric bass, electric organ, synthesizers and drum machine to convert the signal from the pickup or other sound source into an electronic signal that has enough power, due to being routed through a power amplifier, capable of driving one or more loudspeaker that can be heard by the performers and audience.
  Combination amplifiers include a preamplifier, a power amplifier, tone controls, and one or more speakers in a cabinet, a housing or box usually made of hardwood, plywood or particleboard. Instrument amplifiers for some instruments are also available without an internal speaker; these amplifiers, called heads, must plug into one or more external speaker cabinets. Instrument amplifiers also have features that let the performer modify the signal's tone, such as changing the equalization or adding electronic effects such as intentional distortion/overdrive, reverb or chorus effect.
context_section_description: Vacuum tubes were the dominant active electronic components in amplifiers from the 1930s through the early 1970s, and tube amplifiers remain preferred by many musicians and producers. Some musicians feel that tube amplifiers produce a "warmer" or more "natural" sound than solid state units, and a more pleasing overdrive sound when overdriven. However, these subjective assessments of the attributes of tube amplifiers' sound qualities are the subject of ongoing debate. Tube amps are more fragile, require more maintenance, and are usually more expensive than solid state amps.
  Tube amplifiers produce more heat than solid state amplifiers, but few manufacturers of these units include cooling fans in the chassis. While tube amplifiers do need to attain a proper operating temperature, if the temperature goes above this operating temperature, it may shorten the tubes' lifespan and lead to tonal inconsistencies.
caption: A Trace Elliot "Bonneville" tube amplifier as seen from the rear view: note the vacuum tubes extending into the wooden cabinet.
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