To buy an amplifier or not???

Quote:

Originally Posted by Sarge101st 

Hey audio enthusiast readers. I have a question that I thought I'd pose on the forums since there are generalized answers available but nothing concrete on recommendations.

I currently have a nice setup for my personal home theater. I know that nice is perspective based. My question comes into play with amplifiers over my receivers capabilities when driving my speakers. My set up is as follows below

Receiver: Denon AVR-990

Speakers:

Front L/R: Klipsch F30 x 2
Surround L/R: Klipsch Icon VF-35 (Best Buy model)
Center: Klipsch RC-62 II
Subwoofer: Klipsch RW-12D

All speakers are running 12 ga. speaker wire with monster banana plugs for hook up. No speaker wire run will exceed 25ft. in wire distance. Subwoofer will run a 6 ft. c2g cable.

I've recently been completely revamping my AV setup in the house once I got an external bluray reader. I hooked up a 1 y.o. Acer laptop with a cracked screen to the receiver and dedicated it to HTPC duties. Currently I'm ripping every bluray I've got to the two 4TB external hard drives hooked up to the laptops two USB 3.0 ports. Next week I'm running all wires up through the walls for a clean look.

My question comes into play with whether I should purchase an amplifier to power the speakers or not. I know the AVR-990 says it is rated at 120W per channel and I'm looking at either the Emotiva UPA500 or XPA500. Will I see a significant upgrade in sound quality with the UPA500 powering the speakers through the receiver? Should I step up to the XPA 500 since the UPA is only rated at 80W per channel at 8 ohms? Last question is would the UPA700 with the front left and right speakers bi-wired sound better than the UPA500 with standard hook up? Any recommendations from pros out there? Thank you for any feedback.

Does your current AVR have preouts?  If not, then you cannot hook an external amp to it, so you would need to buy an AVR that had preouts. If you are going to buy a new AVR, then you may as well get one of the flagship models with plenty of power as it would almost certainly be enough for those efficient speakers you own. I would guess you are not running out of power in your current setup and thus driving your current AVR into clipping?  If you are not clipping the amp you already use, you won't get any benefit from a more powerful amp in the same system. 

Here is a reply I gave to a similar question recently in another thread:

You need 'enough' amplifier power. Anything more than enough is wasted. The tricky bit is deciding what is enough ;)  The amount of amp power you need is a function of various things: the SPLs you want to listen at, the distance you sit from your speakers, the efficiency rating of your speakers being the most significant.  All speaker manufacturers publish the efficiency rating of their speakers - it looks something like 86dB/1w/1m. This means the speaker will play at 86dB if you feed it 1 watt and measure it at 1 metre. For every 3dB you raise the required SPL, you need double the amp power - so if you want to hit peaks of, say, 105dB (the reference for movie sound reproduction), then, in this example, you would need an amp that can deliver about 65 watts. The further you sit from the speakers and the speaker placement in the room (close to walls, in or out of corners etc) also comes into it. The easiest way to determine the amp power you need in your room is to use a calculator like this:

http://myhometheater.homestead.com/splcalculator.html

You will also need to ensure that your chosen speakers can handle the power required to hit the SPL you want. Remember that you need to cater for peaks, not average SPLs, and you can be listening at 85dB average (reasonably loud) but you will need headroom to handle peaks of 105dB in my example. If you do not have the headroom required you will compress the dynamic range of the content (the ratio between the softest and loudest sounds) and/or you will run the amp into clipping. Clipping is potentially dangerous as it can cause your speaker drivers, especially tweeters, to be damaged. Clipping is caused when you ask the amp to deliver more than its rated power. (Rated power is quoted as xxx watts at a given level of distortion).

It is safe, and even recommended, that your amp can deliver rather more clean power than your speaker manufacturer specifies as the handling capability of the speaker. This means you avoid the dangers of clipping the amp when trying to hit those peaks and you will not harm your speakers by using an amp with good reserves of power. You will not 'overdrive' the speakers because your ears will readily hear any distortion caused by overdriving and you will turn down the volume accordingly. 

Given all of the above, most decent modern AVRs can drive most speakers in most rooms to the levels most people want. The only way to know how much is needed in your specific case is to answer the questions posed above, use the calculator and then decide. If in doubt, err on the side of more power to be on the safe side. Also bear in mind that you may want to change your speakers in the future and you might want to make provision for less efficient designs or 4 ohm designs (some of the lesser AVRs struggle with 4 ohm loads).

The thing about a separate amp is that once you have it, it will last for decades. Receivers introduce new features annually, some of which you may want and some which you don't - but if you have a separate amp you can just install it and forget it - changing just the AVR used as a prepro) whenever necessary to gain new features - eg new sound codecs etc.

WRT to biwiring - just forget it. It's a waste of wire. Have a read of this article for why:

http://www.chuckhawks.com/bi-wire_bi-amp.htm