Difference between audio amplifier & OPAMP
An audio amplifier is a general term that applies to any amplifier specifically designed to cover the audio spectrum, and usually referres to power amplifiers (of any power from micro headphone amps (like the headphone audio amplifier circuit in an ipod) . to power amps like the ones used at rock concerts that are several thousand watts).
An OP-AMP is an Operational Amplifier, which refers to a type of amplifier circuit. Op-Amps can amplify audio, but are not restricted to it. They are used in many things from audio circuitry to signal conditioning, and sensing from all kinds of equipment from seismometers, to light sensors, temp sensors, insturmentation amps, lab amps... RF amps etc...
There are many many different types of op-amps that are designed for many different applications. Mostly the parameters are frequency response, gain, and input/output impedance.
Op-amps usually come in an IC package of some sort. The most common are 8 pin DIP package types.
Op-amps do NOT handle power. (although there are some hybrid power op-amps available, they are specialty devices) The term op-amp refers to the ability of the amplifier to be manipulated mathematically by external values. (i.e. resistors set up to add, subtract, or multiply the value of the input signal) Hence the term OPERATIONAL amp, because it is performing mathematical operations on the signal. (They were first used in analog computers, allowing the voltages to be added, subtracted, and such, and displaying the resultt by directly reading the voltage value).
They handle only small signals, and require being followed by a POWER amp to do anything useful, such as drive a spleaker, or a relay, or a transducer.
For your question, most all audio amps consist of stages.
There is an input/pre-amp stage (this is usually where the eqalization, signal processing, and bass/trebel tone controls are implelented) and a power amp (output) stage that takes the signal fromthe pre-amp and raises the voltage and current to a sufficient level to drive speaker.
The input/pre-amp stage is most usually composed of a series of op-amps. Op amps also are responsible for the bass/trebel control, and the EQ.
There will most usually always be several Op-Amps in every Audio Amp.
Jun 12, 2009 |
Amplifiers & Preamps