Amp Power to Speaker Power Rating

[Billiam62]

I figured before I plunk down a few more bucks for a new set of speakers I should get the right answer to the following question.

At one time I know it was advisable to purchase a pair of speakers that were rated for at least twice the power of the amp that was driving them. Is this still the case? Or has technology changed whereby I could use say a 50 watt integrated amp (4 ohm to 8 ohm) and a pair of speakers rated only to handle say 75 watts?

Any thoughts?

[Feanor]

I figured before I plunk down a few more bucks for a new set of speakers I should get the right answer to the following question.

At one time I know it was advisable to purchase a pair of speakers that were rated for at least twice the power of the amp that was driving them. Is this still the case? Or has technology changed whereby I could use say a 50 watt integrated amp (4 ohm to 8 ohm) and a pair of speakers rated only to handle say 75 watts?

Any thoughts?

Sorry, Bill.

Total misinformation. Got speakers rated for 100 watts power? Want to use it with an amp spec'd at 400 wpc? Really it's no problem.

The amount of power the speakers receive depends on how loud you play them which is controlled byy the volume control setting you set. For a given loudness the speakers will draw the same power from the amp regardless of the amp's maximum output. In fact an amp with too little power capability to drive the speakers to the level you want is more likely to harm your speakers than an amp with much more power.

[JohnMichael]

Speaker power ratings consider the maximum continuous power they can handle. Rarely is an amp's output that high. Most of the time the amp's output is low until the music reaches a peak that requires more power but usually briefly. I have to say I could not tell you the power handling of any of my speakers.

Paying attention to the speaker's efficiency is more important IMHO. This spec will tell you if you have enough amp for the speaker, room size and how loud you listen. An underpowered amp going into clipping creates distortion that destroys tweeters.

[harley .guy07]

I totally agree with the others hear. I used to be a high end dealer and worked with a lot of brands of gear over the years and I have seen low power amps blow tweeters and hurt speakers over high power amps ten fold or more. Generally what happens is that people with the lower power amps will try to drive their speakers past the ability of the lower power amps power supply causing clipping and distortion which in turn hurts the speakers. Having more power generally only helps keep the clipping distortion to a minimum and in turn drives the speakers better when they are playing dynamic material and thus the speaker is drivin more soundly which is healthier for the speakers.

[Unworthy]

I would just like to add one thing. While it is true that the amount of power going into your speakers is controlled by the volume control, this doesn't take into consideration the possibility of "accidental inputs" and it only takes a nanosecond of an extreme spike to damage a speaker. Personally, I would never put an amp in front of speakers that had a higher output rating than the peak rating of the speakers. That's just me.

[Billiam62]

Thanks for the info. Unworthy. Completely agree. I won't even attempt that.

John Michael. I am going to try to find a speaker that is rated at least at 87 db into 4 to 8 ohms. I am going to buy the following and I need to find a pair of bookshelf speakers that will work properly with this amp.

Topping TP60 Tripath TA2022 50WPC (80WPC 4 Ohm) Amplifier | 310-326 (http://www.parts-express.com/topping-tp60-tripath-ta2022-50wpc-(80wpc-4-ohm)-mini-amplifier--310-326)

Had to change my original speaker plans after seeing my new living room's back wall has a fireplace jutting out of it. Need something that is either front ported or not ported at all.

[blackraven]

I have to agree with Harley, JM and Feanor. Ignore the power rating of your speakers. I have a system with PSB B6 bookshelf speaker's with a max recommended power of 150watts. It is paired with a 400wpc Parasound Halo A21 amp and we play the music very loud at times with no damage to the speakers.

You can do more damage to the speakers with an under powered amp.

I would be careful with that topping amp and low sensitivity speakers especially speakers rated at 4 ohms. You will clip that amp as it probably has high distortion levels (as most of these type of amps do) when it approaches 50wpc (that is why you don't see the THD ratings of this amp, it is typically around 10% at its higher power rating). You won't be able to play it very loud with out clipping. I use a similar amp with my Monitor Audio S1 speakers, about 87db and 6ohms My little 50wpc digital amp does great until turned up 1/2 way on the volume. The Topping amp will also sound better if you use a preamp with it, especially a tube preamp. Usually with these little amps they are good for about 1/2 of their power ratings.

I would look for speakers 89db or higher and at least 6 ohms or higher if you are going to use that amp and play it loud.

I found the spec's on this amp and you will see that it is rated at 0.1% THD at 8 ohms at 27wpc and at 4 ohms at 48wpc. The THD distortion usually sky rockets to 10% at their full rated power in these amps. They are great little amps but the power ratings can be misleading.

TOPPING TP60 (http://www.tpdz.net/en/products/tp60.htm)

[Billiam62]

I have to agree with Harley, JM and Feanor. Ignore the power rating of your speakers. I have a system with PSB B6 bookshelf speaker's with a max recommended power of 150watts. It is paired with a 400wpc Parasound Halo A21 amp and we play the music very loud at times with no damage to the speakers.

You can do more damage to the speakers with an under powered amp.

I would be careful with that topping amp and low sensitivity speakers especially speakers rated at 4 ohms. You will clip that amp as it probably has high distortion levels (as most of these type of amps do) when it approaches 50wpc (that is why you don't see the THD ratings of this amp, it is typically around 10% at its higher power rating). You won't be able to play it very loud with out clipping. I use a similar amp with my Monitor Audio S1 speakers, about 87db and 6ohms My little 50wpc digital amp does great until turned up 1/2 way on the volume. The Topping amp will also sound better if you use a preamp with it, especially a tube preamp. Usually with these little amps they are good for about 1/2 of their power ratings.

I would look for speakers 89db or higher and at least 6 ohms or higher if you are going to use that amp and play it loud.

I found the spec's on this amp and you will see that it is rated at 0.1% THD at 8 ohms at 27wpc and at 4 ohms at 48wpc. The THD distortion usually sky rockets to 10% at their full rated power in these amps. They are great little amps but the power ratings can be misleading.

TOPPING TP60 (http://www.tpdz.net/en/products/tp60.htm)

This is extremely useful information. I will definitely use either a 6 ohm or 8 ohm speaker and find one that is more sensitive. Knowing what I do now, I doubt I will play this very loud. I still have my Qinpu A3 and I can easily crank that up to a level that is more than adequate at the times when I need loud audio such as when I am in another part of the house. That is not that often.