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Chapter 3: Glossary of Terms 27
English
Amplifi er Application Guide
In This Chapter
• Glossary of Terms
T
his section provides a handy glossary of terms used in the discussion of profes-
sional audio amplifi ers. Some terms are unique to Crown amplifi ers. Most of the
terms provided do not directly relate to amplifi ers, but as amplifi ers are but one piece
of a larger audio system, are often used when discussing amp usage.
Chapter 3
Glossary of Terms
Amperage
A measure of electrical current fl ow, also called “amps” for
short. It literally equates to the number of electrons in a
conductor fl owing past a certain point in a given amount of
time. Ohms law defi nes current (I) as voltage (V) divided by
resistance (R) with the following expression: I=V/R.
Amplifi er (Amp)
A device that increases signal. Many types of amplifi ers are
used in audio systems. Amplifi ers typically increase voltage,
current, or both.
Amplifi er Class
Audio power amplifi ers are classifi ed primarily by the design
of the output stage. Classifi cation is based on the amount
of time the output devices are made to operate during each
cycle of swing. Amplifi ers are also defi ned in terms of output
bias current (the amount of current fl owing in the output
devices with no signal present). Common amplifi er classes
used in professional audio amplifi ers include AB, AB+B, D, G
and H.
Attenuation
A decrease in the level of a signal is referred to as attenua-
tion. In some cases this is unintentional, as in the attenuation
caused by using wire for signal transmission. Attenuators
(circuits which attenuate a signal) may also be used to lower
the level of a signal in an audio system to prevent overload
and distortion.
Balanced Line
A cable with two conductors surrounded by a shield, in which
each conductor is at equal impedance to ground. With respect
to ground, the conductors are at equal potential but opposite
polarity; the signal fl ows through both conductors.
Band-Pass Filter
In a crossover, a fi lter that passes a band or range of frequen-
cies but sharply attenuates or rejects frequencies outside the
band.
Barrier Block/Barrier Strip
A series of connections, usually screw terminals, arranged
in a line to permanently connect multiple audio lines to such
devices as recording equipment, mixers, or outboard gear.
Also called terminal strip.
BCA
®
BCA (Balanced Current Amplifi er) is Crown’s patented PWM
(Pulse-Width Modulation) amplifi er output stage topology.
Also referred to as “class-I,” Crown’s BCA “switching” technol-
ogy provides for high output, exceptional reliability and nearly
twice the effi ciency of typical amplifi er designs. To learn more
about BCA, download and read the BCA white paper at www.
crownaudio.com.
Binding Post (5-Way, Banana)
A type of electrical terminal, a binding post is most commonly
found as the output connector on a power amplifi er, or as the
connectors on a speaker cabinet. A binding post can accept
banana plugs, spade lugs, bare wire and others. Generally,
binding posts are color coded, with the black connection
going to ground, and the red connecting to hot.
Bridge-Mono
An operating mode of an amplifi er that allows a single input
to feed two combined output channels in order to provide a
single output with twice the voltage of an individual channel in
Stereo or Dual mode.