Can you ever have too powerful amp for speakers?


Can you ever have "too powerful amp for speakers"?
Suppose you have a 300 watt per channel amp driving speakers that only demand, say 80-100 watts a channel or have high enough sensitivity, or a regular 8 ohm load, will some massive Audio Research or Krell amp, even if it is far in excess of what the speaker needs, it should be fine, right? You just never end up turning your preamp volume pot up very loud...or is it better to have an amp that you can peg the preamp much higher say 12 noon or 2 o clock?
dustbowl
usually its power amps with poor designed power supplies that cause the most damage to speakers...
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No, not if you use good judgement. It is far better to have power that is not used than to need it and not have it.
I agree with Stanwal. Never enough clean watts when accompanied with High Current and quality built. Control of speaker and far less chance of distortion. Cheers
Most speaker damage occurs during an event called 'clipping'. This happens when you overdrive an underpowered amp. It's much harder to damage a speaker when using clean power. So if your speakers are rated 80-100 wpc, a 50 wpc amp has a much higher chance of damaging your speakers than a 300 wpc amp.
If you have smaller minimonitors and play records... those big amps can bottom out the woofs with record warp or transient kick drum hits (happened to me). So... easy does it.
300 watts on 100W speakers is ideal; plenty of clean headroom. I've sometimes gone as much as 5 to 1. Only throwing all common sense out the window (regarding drive levels) would cause any problems. Go for it!
It's obviously more "dangerous" than having the recommended power amp rating. While common sense user practices can prevent most mishaps, there are circumstances beyond the user's control. Here's two:

- A short term power outage can turn your system off and then on. If that happens your preamp could send out a transient pulse that could easily fry your speaker's voice coils.

- Your neighbor has a heart attack and your street is quickly crowded with emergency responders. Suddenly bursts of radio chatter come through your system...and then silence.

The above people saying there won't be any problems are not being completely accurate.
The only downside IMO is some very high powered tube amps may be noisy with ultra efficient speakers.

YMMV
Well,i had Odyssey(150w/ch) Stratos Extreme monos(which i soon sold)on a pair of paradigm Studio 60 and was going to upgrade at some point and got a good deal on a Bryston 14bsst(600w/ch).I was using a Anthem D1 pre/pro at the time and when i turned up the volume to the Odyssey levels,the Bryston was so much cleaner and clearer that the woofer in the studio 60's farted and at that point i new i had to sell them or i would have destryed them.I purchased a pair of PMC IB1's soon after.Toooo much CLEAN power is addictive and may push you on the upgrade path.
Diminishing returns perhaps in terms of value for some (that never stopped a true audiophile with deep pockets before however), but recent more cost effective Class D amps which are also highly efficient and deliver top notch sound kind of changes the parameters here as well.
Feil has a good point!

"Some of the big monsters are not light on there feet. They only do big well."

I know of one discerning person who is using a 500w/ch Class D icepower amp with 109 db efficient horn speakers. Overkill perhaps but that person has reported top notch results and a hesitancy to change.
From my experience, is better to have an amp that has higher power rating than the speakers, as gain settings are essential for your equipment durability.


The degree to which the volume knob gets twisted depends on the gain of both the preamp and amp (s) and the sensitivity of the squeakers…. mostly. This may or may not relate proportionately to the amount of power on tap. It does relate to the amount of power being generated/used for a certain volume level for a certain distance.

The more sensitive the squeakers, the less the knob gets twisted up… be it a 100, 200 or 350wpc amp.

Factors that play into this scenario are the amount of gain the preamp provides, the input impedance of the amp as it relates to the output imp of the preamp, impedance curve of the speaker system, their sensitivity, the distance from them to the listening position and the desired SPL.

For ex… Merely lowering the input imp of the amp alone, will force the volume knob upwards if all else remains the same.

Lowering the sensitivity of the loudspakers will force the knob up too.

The size of the room also will come into play regarding the spot the volume level resides at more often than not.

So there are several variables at play as to where the control gets to routinely.

The only bad spot for the volume knob as I understand it is setting it past 1-2 o’clock. If at 2 o’clock you ain’t satisfied with the SPL/vol level, some changes are in order for that system.

I’ve also heard here via other threads, depending on the type volume pot itself, (passive preamps?) the knob needs to be well into it’s range to realize less resistance and greater fidelity. Still I’d think getting past the 2PM spot a dicey situation, and not recommend doing it..

More power though is not a bad thing. Tons of info via many threads here will indicate just that. Each systems power needs or output will have it’s own precautions and configurations as the result.

Personally, I’d not lower my available power output just to get my volume knob farther up into it’s overall range.

If my preamp volume gets to the noon position, it’s because I’ve gone stone deaf, or very nearly. It’s either that or the neighbors across the street want to hear it too…. or I feel they should.
Alot of times speakers get blown when the amp starts clipping because of not enough power.
Blindjim,

Good stuff.

I'd add that in addition to sensitivity, speaker design and directionality can matter. More directional speakers will produce higher SPLs at the sweet spot than less directional or omni design speakers. The reason should be apparent, its like the pressure generated by a garden hose nozzle delivering a focused stream of water versus one that is set to more of a spray pattern.

With omni speakers, there is more leeway to up the volume further without being blasted out of the room, all other factors aside. I percieve higher listening levels to be less fatiguing on my omnis as well in comparison to my more directional monitor speakers. With omnis, lots of power can really be put to good use with less danger of damaging your ears as well IMHO.
The volume control position also depends on the source, my phono settings are considerably higher than ones for CD.
The gain of an amp does not change. It will amplify the signal exactly the same regardless of the level of the signal, or it will try to. So an amp rated 200 WPC into 8 resistive ohms, with an input sensitivity of say 1 volt would give an output voltage of square root of 200 times 8 or 40 volts. However, into an 8 ohm resistive load, this also translates into a current of square root of 200 divided by 8 or 5 amps. However, peak current implies multiplying this by square root of 2 or 7.0711 amps per channel. So, if the speaker can handle forty volts and 7.07 amps, then we are good. But, it also comes down to movement of air. The signal coming from the amp to the speaker is translated into the movement of air to make sound. Therefore, for conventional speakers with cones, the cones actually move at a particular frequency, move air and thus makes sound. Trying to force a speaker cone to move too far or too fast or putting too much current or voltage through or across the speaker is what makes it break or fry. All that said, if you have a volume control on your pre-amp, just keep it down to respectful levels and the speaker would never get close to seeing 200 watts. Unless it shorts, then you have a very different problem. Seriously, most listeners would get blown out of the room at 20 WPC of clean signal and amplification. If you have meters on your equipment, you can see, you rarely if ever get max output power from the amp. Not even close. Especially if your pre-amp's volume control is cranked down. One needs powerful amps for dynamics and especially for difficult speaker loads. That is why efficient horn speakers don't really need much power to drive them.

I may have gotten peak current/voltage mixed up, (it's been awhile), don't have a cow, the result is the same.

I hope this helps.

Enjoy