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almagg
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Last seen: 1 year 3 months ago
Joined: Jun 26 2013 - 7:18am
amp for just purchased Boston Acoustic CR7 speakers

BA CR7 50wpc

in general i was wondering what range of amp wattage i would need
e.g., i gather that 100 watt speakers powered by a 1000 watt amp is not a good idea; same for 100 watt speakers powered by a 10 watt amp

i have seen integrated amps from 30wpc-60wpc so how low or high should i consider?

i was also thinking of waiting till i found something locally instead of off ebay e.g., the Rotel is "...being sold with no warranties, returns or exchanges" - that can't be good.

thanks for any input

here are some that i have seen

Kenwood 3500 - 40wpc
http://www.ebay.com/itm/ws/eBayISAPI.dll?ViewItem&item=290939261815&item...

Kenwood 7100 - 60wpc
http://www.ebay.com/itm/Kenwood-ka-7100-Vintage-Integrated-Amplifier-Gre...?

pt=Vintage_Electronics_R2&hash=item19ded595e3

Harmon Kardon PM640 - 45wpc
http://www.ebay.com/itm/HARMAN-KARDON-PM640-Vxi-INTEGRATED-AMPLIFIER-COM...?

pt=US_Home_Audio_Amplifiers_Preamps&hash=item2a2e6c260f

Denon PM A700 - 50wpc
http://www.ebay.com/itm/Denon-PMA-700V-Integrated-Amplifier-Amp-PMA-700-...?

pt=US_Home_Audio_Amplifiers_Preamps&hash=item56582aaf58

Marantz 1060 - 30wpc
http://www.ebay.com/itm/Marantz-1060-Integrated-Amp-/141007278926?pt=Vin...

NAD - 35wpc
http://miami.craigslist.org/pbc/ele/3912391215.html

Rotel - 50wpc
http://www.ebay.com/itm/ROTEL-RA-840BX4-Stereo-Integrated-Amplifier-Hi-F...

Reserve-/261238902142?pt=US_Home_Audio_Amplifiers_Preamps&hash=item3cd30d4d7e
 

Chuckdog
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Joined: Jul 8 2013 - 4:16pm
Most speaker damage occurs

Most speaker damage occurs when under powered amps are driven into clipping. A clean 150 watt source is much less likely to do damage to your speakers.

I've become a fan of Peachtree Audio and NAD integrated amps in recent years,

commsysman
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Joined: Apr 4 2006 - 11:33am
Amplifier

An amplifier that can put out 150 watts RMS, for example, will seldom do so, because speakers seldom need more than a few watts, except on momentary peaks, but it CAN overheat a speaker that has  a lower continuous power rating.

An amplifier that is rated for 50 watts RMS with low distortion will put out perhaps  an actual 65-75 watts maximum when driven into clipping, so this is NOT usually what causes speaker damage. That is an "old wive's tale" that makes no sense when you do the math for a real situation. This gets repeated over and over by people who do not understand the theory involved and so some people end up believing it. It's just not true that amplifiers will put out some huge amount of power way beyond their rating when they clip.

Speaker damage is USUALLY caused by playing a speaker at or near its power limit for an extended period of time. This causes the voice coil of a driver to overheat and its materials to char or burn, causing physical failure.

In most cases this occurs because the amplifier is able to put out the required amount of power to overheat the drivers, with little audible distortion to warn the listener of a problem. It has the capability to put out more sustained power than the speaker can dissipate as heat.

In other words, an amplifier that is too powerful for the speaker is what usually does the damage, combined with someone dumb enough to play the speakers too loud.

The NAD C326BEE is a very good amplifier that would be a good match for those speakers.

The Cambridge Audio 351 is another one that would be a good choice.

The Boston Acoustics CR7 User's Manual, by the way, says that amplifiers rated for any power between 20 watts and 100 watts RMS are reconmmended for use with them. I don't see an actual maximum power rating for the speaker in the manual or on any website I could find.

 

 

Chuckdog wrote:

Most speaker damage occurs when under powered amps are driven into clipping. A clean 150 watt source is much less likely to do damage to your speakers.

I've become a fan of Peachtree Audio and NAD integrated amps in recent years,

Chuckdog
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Joined: Jul 8 2013 - 4:16pm
I stand corrected on my ex-wive's tales?

It has been my experience that when a bit of common sense is applied, regardless of power ratings of either, any amp driving speakers at an undistored level should be fine.

Speaking only from my own experience, (in my youth of course) I don't recall damaging any speaker with too much power. I do seem to recall blown protection fuses and an open tweeter or two with 35 - 50 watt per channel range amps.

Whether caused by too little or too much power driving speakers into harms way/distress ain't good for your ears or drivers.

The loose nut in front of the volume control has the power to best protect their drivers. 

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