pairing low watt amp with speakers

brooksbp

Looking for technical advice on how to pair amps with speakers.

In the past I had a pair of Polk RTI A1s (20-125 wpc @8ohms) and drove them with a Sony receiver delivering 90 wpc. I eventually blew one of the speakers due to what I believe is called clipping.

Apparently you're suppose to pair speakers with amps that have at least the same wpc -- some people recommend that amps should have double the wpc of whatever your speakers can handle. This avoids clipping and damage to your speakers...

However, I've seen setups that have nice floorstanding speakers paired with low wattage amps e.g. B&W 804 (50-200 wpc) paired with a Rotel RA-1062 (60 wpc). How is this safe??? I've also seen expensive tube amps that have extremely low wattage. This seems risky..

blehmbo

Wattage ratings from one company are not always equal to wattage ratings from another company. Some companies make their ratings with one channel driven and some give their ratings with 2 channels, 5 channels, etc. Most AVRs and some amplifiers come with power supplies that are not sufficient enough to give the rated power to all channels.

fishbones

blehmbo is correct! AVR's are notorious for overstating their wattage per channel...and, While some AVR's might have a higher power rating, it doesn't mean it's clean power when cranked up. If you like to crank it up, then you need to get a separate amplifier that is built with better circuitry. It will give you cleaner power at higher volumes and better sound all the way around.

It also has to do with how a speaker is designed. Some speakers can do well with low wattage and other speakers are designed around higher wattage applications. If you're looking at getting new speakers, you might have to be willing to change amplification to make them shine. I just got new speakers that sound their best with 30-40 watt amps, but they are designed more for 2-channel only listening.

treitz3

Another thing you must consider is wattage is a completely different animal than current [or amps]. Tube amps are generally higher current amps than that of an SS amp, [especially an AVR] and 4 watts can produce the same volume as 180 watts with the correct efficiency of a speaker, which also draws into play.

treitz3

Here's a couple of links you may not have run across that's from this website. It's under the "support" tab on the top of the page, no matter what page you are on. after you click on that tab, click onto the "Education and FAQ" tab.

http://www.polkaudio.com/education/article.php?id=4

http://www.polkaudio.com/education/showanswer.php?question_num=46

This should help you understand a bit better. If you have any other questions, feel free to ask.

madmax

I've found amps around the 100wpc to be the most dangerous. While you can often achieve the volume you want, if you go a little higher you start clipping and there is enough raw power available to burn out a speaker. With twice the wattage you end up with much less chance of clipping, with 4 times as much you will never clip unless you keep turning up to unreasonable levels. Below 50 or 60 watts you may be able to clip all day but may not have enough raw uncontrolled power available to cause damage.

steveinaz

Good point Max.

nhhiep

WPC is 1 thing, but I usually pay more attention to the current of the AMP, and especially the THD at their rated WPC, in addition to the frequency range @ x ohms. Some rated it at 1khz, others from 20-20khz.

Many low end AVRs cheated by listing at 1khz, 6ohms and .5-1% THD. I once saw a Samsung AVR rated at 10% THD.... OMG

Joe08867

Current over power. I do fall in the 200watt club mostly but like treitz3 stated Tubes usually have more current than SS amps.

I have run SDA's on a 15watt tube amp that was honestly just as loud as a 200watt Solid State Amplifier.

It also depends on how you listen. Cranking up tunes at a party or critical. Parties are notorious for blowing speakers. If you go with another AVR I would suggest some constraint on the volume control.