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What is the function of amplifier, pre-amp, equalizer in home audio system? Are they needed for good system?

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What is the function of amplifier, pre-amp, equalizer in home audio system? Are they needed for good system?

Postby fulumirani46 » Sun Aug 12, 2012 9:01 pm

An amplifier, or power-amp, supplies the power that drives your loudspeakers.

A pre-amp, or processor, does all the decoding of the incoming audio stream from the DVD/cable/sat/etc., adjusts volume, selects source, etc. AND sends it to the power-amp. Most newer pre-amps have built in equalizers and set-up programs that automatically adjust the level (volume) of each speaker, sets distances, etc.through a supplied microphone that you place in your seating position.

An A/V receiver generally combines eveything into one piece of equipment.

Pre-amps and power-amps are generally considered PREMIUM or HIGH-END and as such, they usually cost much more than a simple receiver. They're also built to a higher standard.
Some of the advantages are that with the amps seperated from the processing, there's no electrical interference or "crosstalk" with the processor caused by the amp section.
Another is that a power amp will generally have MUCH more power than a receiver. More power equals more "headroom" or reserves for musical or cinematic peaks while listening to music and watching movies.
So yes, they are superior, but you really need at least some decent speakers to exploit the benefits.

Some people pair a power amp with a receiver, using the receiver as a pre-amp to reap the benefits of the REAL power of a seperate amp. Most $500-800 receivers rated at 120watts by 7 channels only put out 60-70 watts when you're actually using all 7 speakers.

Here is an used Rotal power amp that would blow away any sub $1,000 receiver in clean, reserve filled power output :
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What is the function of amplifier, pre-amp, equalizer in home audio system? Are they needed for good system?

Postby kempe » Sun Aug 12, 2012 9:09 pm

Although Pre-amp/Amp/Tunder is preferred by Audiofiles. There are some first rate A/V Receivers on the market that provide great sound. I would rather have a great A/V Reciever than a good pre-amp/amp/tuner. Seperates can get quite expensive over a single A/V reciever. If you plan a 7.1 surround system, they are great bet and much less cost! I would argue the sound quality of a Arcam noted below over a seperate system. Arcam does offer separates as well.

I would recommend Arcam DiVA AVR350 surround sound receiver from England over many re-amp/amp/tuners. They are very highly rated and for $2600 they are a steal! If you want a more reasonable unit that provides very good sound and features take a look at the Pioneer 84TSXi for about $1400.00. I ahve the 82 model and have been very happy with the sound.. But I plan on upgrading to Arcam next year, I have a Arcam CD73 Cd player and it great sounding.
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What is the function of amplifier, pre-amp, equalizer in home audio system? Are they needed for good system?

Postby stanwic » Sun Aug 12, 2012 9:13 pm

Hi. A Power Amplifier amplifies the low output of the front end (Pre-Amp DVD/CD/ Player,Turntable,Tuner etc) sufficient enough to drive the speakers that produce the sound.
A Pre-Amplifier is a separate unit that amplifies the front end equipment then sends its signal to a Power Amplifier to further amplify the signal that goes to the speakers. An Equalizer is a separate unit that behaves like the Tone controls on an Amplifier but uses multiple turnover frequencies up to about 10,000hz with boost and cut of 10 db for example .:
20 hz +or-10db. 40hz 80 hz 160 hz 320hz 640 hz 1280hz 2560hz 5120hz 10240hz

A well designed intergrated amplifier would do in most cases.But the best results would be with a separate Pre-amplifier and Power amplifier'
I would give the equaliser a miss cause it would affect the sound negetivly and you would loose some detail.

Here are some examples :





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