Preamplifier
A preamplifier (preamp) is an electronic amplifier that prepares a small electrical signal for further amplification or processing. A preamplifier is often placed close to the sensor to reduce the effects of noise and interference. It is used to boost the signal strength to drive the cable to the main instrument without significantly degrading the signal-to-noise ratio (SNR). The noise performance of a preamplifier is critical. According to Friis's formula, when the gain of the preamplifier is high, the SNR of the final signal is determined by the SNR of the input signal and the noise figure of the preamplifier.
In a home audio system, the term 'preamplifier' may sometimes be used to describe equipment which merely switches between different line level sources and applies a volume control, so that no actual amplification may be involved. In an audio system, the second amplifier is typically a power amplifier (power amp). The preamplifier provides voltage gain (e.g., from 10 mV to 1 V) but no significant current gain. The power amplifier provides the higher current necessary to drive loudspeakers.
Podcasts:
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by Microphones
Preamp
by: Microphones(Phil Elvrum)
I am a preamp.
Plug the cords right in my head.
I've got headphones,
Stuck right into my shirt.
I'm a guitar amp.
I bite the cord between my teeth.
My voice is the speaker,
And my eyes tell how loud I am.
I've got microphone fingers.
I don't care about phantom power,
And I know the levels,
Because I'm a preamp for everything.
(Female Vocalist)
I needed something
To make sure you could hear me
Where was i going
Did the sound just disappear?
You were recording
You kept me on a tape
(You) played it softly
Inside your headphones.
I am a beauty.
I am the voice that sounds sweet.
Playing softly,
Putting you to sleep.
(now here's where Phil gets tricky. The next two sections are sung simultaneously, Phil in the Right channel and the Female vocalist in the Left)
(Phil)
I wanted to keep you,
So I made a tape.
Now I listen,
To your voice singing to me.
(Female)
I am a beauty.
I am the voice that sounds sweet.
Playing softly,
Putting you to sleep.
(Phil)
I am a preamp,
And you're plugged into my heart.
(Female)
I am a beauty,