# What does the 'preamp' do exactly (in the iTunes equalizer)?

**URL:** <https://boards.straightdope.com/t/what-does-the-preamp-do-exactly-in-the-itunes-equalizer/534047>\
**Category:** Factual Questions\
**Created:** [March 27, 2010, 8:02pm UTC](https://boards.straightdope.com/t/what-does-the-preamp-do-exactly-in-the-itunes-equalizer/534047 "2010-03-27T20:02:42Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![KarlGauss](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/karlgauss/32/3713_2.png) [@KarlGauss](https://boards.straightdope.com/u/KarlGauss)\
**Post date:** [March 27, 2010, 8:02pm UTC](https://boards.straightdope.com/t/what-does-the-preamp-do-exactly-in-the-itunes-equalizer/534047/1 "2010-03-27T20:02:42Z")

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What does the ‘preamp’ do exactly (in the iTunes equalizer)? It seems to make things louder, but that can’t be all, can it?

Thanks!

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**Author:** ![beowulff](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/beowulff/32/542_2.png) [@beowulff](https://boards.straightdope.com/u/beowulff)\
**Post date:** [March 27, 2010, 8:41pm UTC](https://boards.straightdope.com/t/what-does-the-preamp-do-exactly-in-the-itunes-equalizer/534047/2 "2010-03-27T20:41:03Z")

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Yes, it allows you to adjust the volume on a song-by-song basis.

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**Author:** ![Hari\_Seldon](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/hari_seldon/32/5173_2.png) [@Hari\_Seldon](https://boards.straightdope.com/u/Hari_Seldon)\
**Post date:** [March 27, 2010, 10:05pm UTC](https://boards.straightdope.com/t/what-does-the-preamp-do-exactly-in-the-itunes-equalizer/534047/3 "2010-03-27T22:05:31Z")

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Back in 1960, when I built my own from kits, the pre-amp was a voltage amplifier that took input from a low voltage source such as a turntable or tuner and turned it into a high voltage, but still low power. You could hook earphones directly to the output, but not a speaker. The amplifier, more properly called a power amplifier, took a high voltage, low power source and without modifying the voltage significantly, produced a high power output. What “high power” meant in this context is that you could hook to a speaker without unduly degrading the signal waves.

This was pre-transistor days, but I think it works much the same with transistors.