25W amp for a 100W speaker?
May 16, 2015 at 3:00 PM Thread Starter Post #1 of 7

Googolplex147

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Sorry for a noob question, but would a 25W amp be able to drive a pair of 100W speakers? I'm looking to buy the Klipsch RB-61 II http://www.amazon.com/Klipsch-Reference-Series-Bookshelf-Loudspeakers/dp/B0040LRI96 and I'm also attracted to the topping vx-1 http://www.amazon.com/TOPPING-Tripath-Subwoofer-Amplifier-Digital/dp/B00H6XDE4S . Would the volume suffer? Would it be safe to use them together? If not, what kind of amp would I need to drive the speakers? Alternatively are there good speakers in that price range that the topping would handle?
 
May 16, 2015 at 3:10 PM Post #2 of 7

Steve Eddy

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Sorry for a noob question, but would a 25W amp be able to drive a pair of 100W speakers? I'm looking to buy the Klipsch RB-61 II http://www.amazon.com/Klipsch-Reference-Series-Bookshelf-Loudspeakers/dp/B0040LRI96 and I'm also attracted to the topping vx-1 http://www.amazon.com/TOPPING-Tripath-Subwoofer-Amplifier-Digital/dp/B00H6XDE4S . Would the volume suffer? Would it be safe to use them together? If not, what kind of amp would I need to drive the speakers? Alternatively are there good speakers in that price range that the topping would handle?


The 100 watts simply refers to the maximum rated power that the speakers can handle, not the amount of power it takes to drive them.

The RB-61 has a sensitivity of 95 dB. That's higher than average. I don't think you'll have any problem at all getting enough volume out of them with 25 watts.

Good luck!

se
 
May 16, 2015 at 6:35 PM Post #3 of 7

Googolplex147

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The 100 watts simply refers to the maximum rated power that the speakers can handle, not the amount of power it takes to drive them.

The RB-61 has a sensitivity of 95 dB. That's higher than average. I don't think you'll have any problem at all getting enough volume out of them with 25 watts.

Good luck!

se

Fantastic, thank you.
 
May 21, 2015 at 11:28 AM Post #5 of 7

Steve Eddy

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I am in a kind a same boat. I have a 50W 5.1 channel Harman Kardon amplifier and would like to buy floor standing speakers. Those are usually around 100-200W or more.


As I said previously, the power rating of the speaker isn't how much power they need to achieve sufficient volume, but how much power you can shove into them before they blow up.


Is it gonna sound less powerful compare to a 100W amp?


If the speakers don't need any more than 50 watts to achieve sufficicient volume, then it's not going to sound any less powerful than if you were using a 1,000 watt amp. And I doubt you'll need more than 50 watts for that unless your speakers are terribly inefficient.


Also what about the Ohms?
Can i use 4 ohms speakers with a 8 ohm amplifier?


Generally speaking, if the amp is not specifically rated for 4 ohm loads, it's a good idea not to use the amp with 4 ohm speakers.

Good luck!

se
 
May 21, 2015 at 1:29 PM Post #6 of 7

cel4145

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^^

Agreed. You an use tower speakers rated 100 to 200 watts with a 50 watt AVR. You just won't be able to run them as a loud before they start to distort.

4 ohm speakers are more difficult to drive. So your AVR may run them if not 4 ohm rated, but it will likely heat up a lot at higher volumes. Might or might not be good for the amp in the AVR over the long term. Plus, some 4 ohm rated speakers actually dip much lower in impedance at certain frequencies, and the amp might not be able to deal with it (automatic protection circuitry will typically kick in and shut down the AVR in that case)--depends on the specific speakers. So best to stick with 6 or 8 ohm speakers since there are so many to choose from :)
 
May 22, 2015 at 7:54 PM Post #7 of 7

SandAndGlass

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The Tripath is a nice little amp. I have a coupe of small Lepai amps that are similar that put out 20-WPC. With 95-db efficiency you will be able to achieve room filling volumes of 75-85 db with less than one watt, with your Klipsch towers. These small amps put out some good watts considering their size and cost. You should be able to achieve 105-db without taxing the amp. I have not personally listened to the Tripath but, with the Lepai's they will be clean to a little over half of their rated output, then they will start to distort.
 
The Tripath, together with the Klipsch will provide you with surprising good sound with a minimum investment. Just don't expect to open up a dubstep dance club in your living room. Then again, they might even be ok at moderate levels.
 
I use a 50 watt (per-channel) amp for my rear Klipsch tower speakers that are about 90-db or so. The front towers are powered by a 250 watt stand alone amp.
 
While your Tripath  will fill your needs for now, keep an eye out on eBay for a Sherbourn LDS2/75 (Sherbourn has now been folded into Emotiva).
 
There are a couple of them on eBay right now, but the asking prices are way too high. I bought a couple on eBay last December and I paid $62 for one and $40 for the other, plus shipping, so keep an eye out. These are commercial quality home amps. They will give you much more clean power, bass and drive. Your Klipsch towers will really open up when they are fed well. The 50-watt Sherbourn that I am using now is a slightly more expensive model. They both have two channels for the input and I use one channel for HT and the other for two channel stereo in the rear and they keep up with the much larger front amp without any problems.
 
I have one of the LDS2/75 on loan to a friend who is listening to a pair of ERA/Peachtree D5 speakers with them. The D5's are only 87-db and they play plenty loud. I used to use a 100-WPC Sherwood receiver for the rear speakers and I replaced the Sherwood with the Sherbourn and the sound is much better, fuller, with a lot more bass.
 
Spend less, get more... ENJOY!
 

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