Discussion in 'AV Receivers' started by Eric_Philips, Aug 11, 2003.

  1. Eric_Philips

    Eric_Philips Extra

    Jun 8, 2002
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    I'm a bit new to Amps and other High End power sources. Could someone help me understand the need for a preamp?

    Also, most amps that I've seen rarely push more than 75-100 watts, but there are speakers that take 250. I understand the whole (twice the watts doesn't = twice the SPLs)

    Is there a good FAQ on Separates, Amps, and PreAmps; if not, could someone just speak on the issue a bit.

  2. DanaA

    DanaA Screenwriter

    Nov 21, 2001
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    In the Home Theater Basics area, there is a guide for beginners. You might want to check that out. Here's what Cees, a moderator here, gives as the functions of source, processor, preamp, and amp:

    " Audio signals come from a source (CD player, DVD player, VHS player), then go to a processor to have it divided for multichannel output (Dolby Surround, DTS, Dolby Digital). Then go to pre-amplifier to get some corrections and make it a standard level (also may have treble and bass regulated- as well as overall volume level), then go to (power-) amplifiers who produce power (voltage times current), so it can drive a speaker and make a lot of noise.

    If the pre-amplifier and the amplifiers are combined (together with a processor and a radio-tuner as well), it's called a receiver. This is the most common solution in a HT. Therefore, if the power-amplifiers are not all inside a receiver, but apart, that's called separates."

    Now me talking:

    Generally, separates cost more to begin with, but offer more flexibility and can actually save you money down the line. Separates are also, for the most part, better sounding than all but a few receivers. A lot of people who use separates state they will never go back to the all-in-one receiver. Here's an article that might explain why separates are usually, not necessarily always, better.
    Click Here

    You can't really rely on the manufacturer's stated power ratings for receivers. They may say that the receiver offers 5 channels of power, each with 100 watts, but, more often than not, this is misleading. Most dedicated amplifiers state their power much more accurately and conservatively.

    You also can't rely totally on a speaker's rating of, let's say, 20-250 watts. There is more danger in undersupplying power, than there is in oversupplying power, not to mention there is much sonic benefit to providing the speakers with ample, clean power. A speaker's sensitivity or efficiency rating is more important. This tells you what a speaker needs to achieve a certain decibel level at one watt at one meter. So, if a receiver has a sensitivity of 90 decibels, that means that at one meter, under tested conditions, it achieves a 90 decibel output with one watt of power.

    It really is a lot more complicated than I have stated. I'd go over to the Home Theater Basics area, click on the sticky toward the top on Frequently Asked Questions and read. I'd also do a lot of searches to try and gain information about specific speakers or amps. There really is an overwhelming amount of information, but the more you know what there is to know, the better choices you'll make down the line. Take your time.

    Here's a link to the Home Theater Forum basics primer:

    I know that all of this might seem like a drag, but once you get your system up and running, you'll know it was worth it.

    One last thing: Before you buy, bounce your ideas off of this board and other boards to get as much feedback as you can. Include a budget and recognize that there are a lot of biases going around. As an example, I recently bought speakers from a company that only sells online. This was a frightening prospect for me, but it turned out wonderfully. I feel I finally got speakers that I don't have the temptation to upgrade at a fantastic price. So, my bias would be to buy speakers from one of the respected online companies. Another persons advise might be to avoid online companies for various reasons. I'm sure you get the point.

    Best of wishes in your pursuit. Hope this helps.

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