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Power Amp recommendation for B&W CM9 S2

dakchi

New member
Apr 9, 2011
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Hi,

I just bought a second hand B&W CM9 S2 that I paired with my amp Cambridge CXA80. I have always heard that B&W CM9 need a lot of power to demonstrate what they are capable of. Although I am satisfied with the combination of the CM9 and the CXA80, I am wondering if adding a power amp would improve the system. I don't have a lot of knowledge about power amps. So I have a few questions to ask you:

* In theory, the power amp function is to amplify the signal coming out of the preamp without changing it. However, in practice, I heard that the power amp can have an impact on the sound. Is this a correct statement?

* B&W CM9 owners usually like the combination with Rotel gears. I remember that I have listened to this combination years ago and I found the sound too bright with almost no bass. I like the warm sound that I get with my cambridge amp. What power amp that does not change the sound of the cambridge would you recommend? my budget for a power amp is 1000 euros max (new or second hand)

Many thanks for your help
 

drummerman

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Jan 18, 2008
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If you like the sound don't mess with it. The beginning of the end :)

I don't think the Cambridge would make the best preamplifier but let's assume it does for a moment then a good powerful amplifier will give you likely more control/ grip. You may loose some of that warmth (lack of control) most likely.

Having said that, it's all complex interaction between speaker and amplifier so there are quite a lot of variations.

Prepared to open a can of worms?
 

dakchi

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Apr 9, 2011
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Why do you think Cambridge cannot make a good preamp? yes I am satisfied with what I get, but I am wondering if I will get more if I add a power amp. I always hear that the more you give power to the B&W the more you get
 

drummerman

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Jan 18, 2008
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Nord do a buy or return scheme AFAIK.

That would be my choice for power. Around 400 real watts p/ch.

Suck it and see.
 

Vladimir

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Dec 26, 2013
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Only pro amps available at a low budget would yield significant power increase. And those have loud turbo fans, so not good for a domestic situation.

If your current CA isn't overheating, it means it handles the low impedance load from the B&Ws well and that's all that you need. If it feels strained when turned up, getting uncomfortably warm to the touch, then it's new amp time. People with AVRs will have this issue more than you will. They would be the ones writing up how much power these CM9s demand. Not 'power', current specifically, with good stability in 2-3ohms. The watts rating is meaningless.

The warmness you are hearing isn't the amp, it's how the Abrahamsen V2.0 UP or a pre-loved s/h Electrocompaniet. They are effectively the same thing, split company, same awesome product. The V2.0 UP has only 70Wpc specified, which again tells you nothing of what the amp can really do.
 

dakchi

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Apr 9, 2011
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I understand from what you all say that adding a power amp is not a good idea. It is better to change the integrated amp IF necessary
 

Vladimir

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Dec 26, 2013
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dakchi said:
I understand from what you all say that adding a power amp is not a good idea. It is better to change the integrated amp IF necessary
It's a good idea if you get a significantly more powerfull power amp compared to your CA and use your integrated as preamp only.

If you get a poweramp of similar power capability as the integrated and bi-amp the speakers, there won't be a significant improvement to justify the investment. Therefore a bad idea.
 

drummerman

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Jan 18, 2008
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Your amplifier has a quoted power consumption of 750w max.

Its a pretty hefty supply as integrateds under a grand go if we exclude the Abrahamsen for a moment and that amplifier is so ugly that even its own mother would disown it.

If you were looking for more power and current you would have to look at 200w + amplifiers with larger supplies to make a significant difference either in loudness or grip.

I dont know every amplifier under the sun but the above is roughly £2000+ territory, the odd exception perhaps excluded. Its also what I think you (or anyone with a £800 integrated) would have to spend to gain anything significant.
 

dakchi

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Apr 9, 2011
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drummerman said:
Your amplifier has a quoted power consumption of 750w max.

Its a pretty hefty supply as integrateds under a grand go if we exclude the Abrahamsen for a moment and that amplifier is so ugly that even its own mother would disown it.

If you were looking for more power and current you would have to look at 200w + amplifiers with larger supplies to make a significant difference either in loudness or grip.

I dont know every amplifier under the sun but the above is roughly £2000+ territory, the odd exception perhaps excluded. Its also what I think you (or anyone with a £800 integrated) would have to spend to gain anything significant.
Ok, if I will have to invest that much to hear an improvment it's a no go for me. I understand from your analysis that the power of an amplifier depends on its power consumption. Is it the only measure we have to take into account to know whether an amp is powerful or not?
 

Blacksabbath25

Well-known member
Sep 20, 2015
309
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10,970
dakchi said:
drummerman said:
Your amplifier has a quoted power consumption of 750w max.

Its a pretty hefty supply as integrateds under a grand go if we exclude the Abrahamsen for a moment and that amplifier is so ugly that even its own mother would disown it.

If you were looking for more power and current you would have to look at 200w + amplifiers with larger supplies to make a significant difference either in loudness or grip.

I dont know every amplifier under the sun but the above is roughly £2000+ territory, the odd exception perhaps excluded. Its also what I think you (or anyone with a £800 integrated) would have to spend to gain anything significant.
Ok, if I will have to invest that much to hear an improvment it's a no go for me. I understand from your analysis that the power of an amplifier depends on its power consumption. Is it the only measure we have to take into account to know whether an amp is powerful or not?
I would say if you want an improvement you have 2 options .. 1 buy a better amplifier that will give you complete control and sonically matching your b&w or option 2 change your speakers to something else that will suit the Cambridge cx80 better

ive been there my self on the power amp idea and it's because there is something about your setup you do not like and that was the same for me and your trying to improve things like buying a power amplifier but this is not going to sort things out .

i think at a guess here it's the speakers that is the problem as your amplifier has no issues with power or it's power supply to control your speakers so it's your speakers not giving you a sonic match with the Cambridge cx80 but if you like your speakers then find a different amplifier that will suit your speakers more on a sonic level .
 

dakchi

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Apr 9, 2011
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Can someone answer my question: what are the technical specifications that we should check to know whether an amplifie is capable of driving a speaker? I know that the output (watts) does not tell anything and that it's all about power. Where can I see how much power an amplifier can deliver? is it in the power consumption?

Thanks
 

drummerman

New member
Jan 18, 2008
540
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dakchi said:
Can someone answer my question: what are the technical specifications that we should check to know whether an amplifie is capable of driving a speaker? I know that the output (watts) does not tell anything and that it's all about power. Where can I see how much power an amplifier can deliver? is it in the power consumption?

Thanks
Watts matter, current matters. It all matters but in the end a sympathetic match between speaker and amp is what matters most.

If you want an amplifier that will power anything, regardless of load, go with an arc welder from Son of Abraham, Krell etc etc..

This may not sound so nice though with super efficient speakers that perhaps benefit from a valve amplifier which may not supply loads of current but does voltage well.

For 'normal users', around a hundred watts and decent current/low output impedance (damping factor of 40+) should cover most bases reasonably well.
 

CnoEvil

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Aug 21, 2009
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dakchi said:
Can someone answer my question: what are the technical specifications that we should check to know whether an amplifie is capable of driving a speaker? I know that the output (watts) does not tell anything and that it's all about power. Where can I see how much power an amplifier can deliver? is it in the power consumption?

Thanks
Look for an amp that gets close to doubling its power as speaker impedance halves.

eg 100W @ 8 Ohms and 200W @ 4 Ohms.....and if you're very lucky, nearly 400W @ 2 Ohms.
 

dakchi

New member
Apr 9, 2011
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0
drummerman said:
dakchi said:
Can someone answer my question: what are the technical specifications that we should check to know whether an amplifie is capable of driving a speaker? I know that the output (watts) does not tell anything and that it's all about power. Where can I see how much power an amplifier can deliver? is it in the power consumption?

Thanks
Watts matter, current matters. It all matters but in the end a sympathetic match between speaker and amp is what matters most.

If you want an amplifier that will power anything, regardless of load, go with an arc welder from Son of Abraham, Krell etc etc..

This may not sound so nice though with super efficient speakers that perhaps benefit from a valve amplifier which may not supply loads of current but does voltage well.

For 'normal users', around a hundred watts and decent current/low output impedance (damping factor of 40+) should cover most bases reasonably well.
Ok, then I have to take into account watts, current and of course matching with speakers. Where do I see if an amp delivers enough current for the speakers?
 

Vladimir

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Dec 26, 2013
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Looking at max power consumption on back of amplifiers is usually something tire kickers do. But if you know what it actually means, it can be usefull indication.

Drummerman was aiming at the capability of amplifiers of otherwise modestly rated power to drive low impedance drops without their voltage rails saging, at least short term. In such impedance drops an amp will spike power consumption due to increased current demand from the speakers and manufacturer disclosed worst case scenario.

But there are some (older) cases where average power consumption is declared, not max, back when conservative ratings existed. Also some class AB amps are less efficient than others (due to higher biasing) so they waste more power from the mains than others, doesn't mean have more power, but a design approach towards lower crossover distortion in the output stages.

Reviewers and audiophiles were getting impressed by the budget Pioneer A400 pushing difficult higher tier speakers with relative ease despite declared 50Wpc. Usually comments were this thing must be at least 80W! 50 or 80 makes little difference. The secret was in the decent power supply and high current Toshiba transistors.
 

drummerman

New member
Jan 18, 2008
540
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0
dakchi said:
drummerman said:
dakchi said:
Can someone answer my question: what are the technical specifications that we should check to know whether an amplifie is capable of driving a speaker? I know that the output (watts) does not tell anything and that it's all about power. Where can I see how much power an amplifier can deliver? is it in the power consumption?

Thanks
Watts matter, current matters. It all matters but in the end a sympathetic match between speaker and amp is what matters most.

If you want an amplifier that will power anything, regardless of load, go with an arc welder from Son of Abraham, Krell etc etc..

This may not sound so nice though with super efficient speakers that perhaps benefit from a valve amplifier which may not supply loads of current but does voltage well.

For 'normal users', around a hundred watts and decent current/low output impedance (damping factor of 40+) should cover most bases reasonably well.
Ok, then I have to take into account watts, current and of course matching with speakers. Where do I see if an amp delivers enough current for the speakers?
Generally speaking, you look at the Speakers impedance, especially minimum impedance, phase angles and minimum EPDR ... equivalent peak dissipation resistance to pinpoint possible amplifier trouble hot spots at their respective frequencies.

Failing all that just buy a well made, modern amp with reasonable power depending on your listening preferences, listen to it with speakers of choice and don't worry too much. :)
 

Vladimir

New member
Dec 26, 2013
220
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0
drummerman said:
dakchi said:
drummerman said:
dakchi said:
Can someone answer my question: what are the technical specifications that we should check to know whether an amplifie is capable of driving a speaker? I know that the output (watts) does not tell anything and that it's all about power. Where can I see how much power an amplifier can deliver? is it in the power consumption?

Thanks
Watts matter, current matters. It all matters but in the end a sympathetic match between speaker and amp is what matters most.

If you want an amplifier that will power anything, regardless of load, go with an arc welder from Son of Abraham, Krell etc etc..

This may not sound so nice though with super efficient speakers that perhaps benefit from a valve amplifier which may not supply loads of current but does voltage well.

For 'normal users', around a hundred watts and decent current/low output impedance (damping factor of 40+) should cover most bases reasonably well.
Ok, then I have to take into account watts, current and of course matching with speakers. Where do I see if an amp delivers enough current for the speakers?
Generally speaking, you look at the Speakers impedance, especially minimum impedance, phase angles and minimum EPDR ... equivalent peak dissipation resistance to pinpoint possible amplifier trouble hot spots at their respective frequencies.

Failing all that just buy a well made, modern amp with reasonable power depending on your listening preferences, listen to it with speakers of choice and don't worry too much. :)
B&W CM10 - EPDR of 1.2ohm at 95Hz, 1.6ohm at 559Hz. CM9 mildly better in the 3ohms range. OP's concern is valid.
 

drummerman

New member
Jan 18, 2008
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Vladimir said:
drummerman said:
dakchi said:
drummerman said:
dakchi said:
Can someone answer my question: what are the technical specifications that we should check to know whether an amplifie is capable of driving a speaker? I know that the output (watts) does not tell anything and that it's all about power. Where can I see how much power an amplifier can deliver? is it in the power consumption?

Thanks
Watts matter, current matters. It all matters but in the end a sympathetic match between speaker and amp is what matters most.

If you want an amplifier that will power anything, regardless of load, go with an arc welder from Son of Abraham, Krell etc etc..

This may not sound so nice though with super efficient speakers that perhaps benefit from a valve amplifier which may not supply loads of current but does voltage well.

For 'normal users', around a hundred watts and decent current/low output impedance (damping factor of 40+) should cover most bases reasonably well.
Ok, then I have to take into account watts, current and of course matching with speakers. Where do I see if an amp delivers enough current for the speakers?
Generally speaking, you look at the Speakers impedance, especially minimum impedance, phase angles and minimum EPDR ... equivalent peak dissipation resistance to pinpoint possible amplifier trouble hot spots at their respective frequencies.

Failing all that just buy a well made, modern amp with reasonable power depending on your listening preferences, listen to it with speakers of choice and don't worry too much. :)
B&W CM10 - EPDR of 1.2ohm at 95Hz, 1.6ohm at 559Hz. CM9 mildly better in the 3ohms range. OP's concern is valid.
Indeed, a difficult load.

Good current/Stability required.

Good shout.
 

dakchi

New member
Apr 9, 2011
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Ok, what does it mean in numbers? if I have to look for an amp, what numbers should I check?
 

sound10

Well-known member
Jun 29, 2010
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Hi dakchi, nice to meet you. I have the CM9 S2"s with the Marantz PM8005 and they make a fantastic combination. Plenty of power and current to drive the CM9's really well. With regards to needing a power amplifier to drive these speakers well I don't think that is necessary at all imho. From looking at the Cambridge Audio amplifier specs I can't see any reason why the amp would have any issues driving the CM9's unless you like to listen at extremely high volume levels or you have a massive room to fill with sound. Just to add that Marantz and Rotel amplifiers go well with Bowers & Wilkins. Perhaps Cambridge Audio products don't and that is where the issue could be. Just to add the Marantz PM8005 is now just under 600.00. That is a fantastic price and will work very well with your CM9's. Hope this helps :)
 

dakchi

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Apr 9, 2011
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sound10 said:
Hi dakchi, nice to meet you. I have the CM9 S2"s with the Marantz PM8005 and they make a fantastic combination. Plenty of power and current to drive the CM9's really well. With regards to needing a power amplifier to drive these speakers well I don't think that is necessary at all imho. From looking at the Cambridge Audio amplifier specs I can't see any reason why the amp would have any issues driving the CM9's unless you like to listen at extremely high volume levels or you have a massive room to fill with sound. Just to add that Marantz and Rotel amplifiers go well with Bowers & Wilkins. Perhaps Cambridge Audio products don't and that is where the issue could be. Just to add the Marantz PM8005 is now just under 600.00. That is a fantastic price and will work very well with your CM9's. Hope this helps :)
Hi sound10,

Thank you for your response. Actually, the Cambridge goes very well with the CM9 and I get very nice musicality. However, I hear everywhere that the CM9 will perform better with powerful amp with high current. I am happy with what I hear now, but if it is worth is, I can add a power amp or even change the Cambridge if there will be a significant improvment. I haven't tried the CM9 with more powerful amp to judge. Maybe I don't have to listen to what people say, as long as I'm happy with what I get. It's my constant search for perfection *fool*
 

sound10

Well-known member
Jun 29, 2010
41
2
18,545
Just to add like other forum members have already said, rated watts per channel of an amplifier is only one part of whether an amplifier will drive a speaker well. What is equally important are the quality of components inside the amplifier especially the quality of the power supply and it's ability to deliver clean and high current as and when it is needed. Another factor is what headroom the amplifier has when it hits a certain load. As previously mentioned by myself on another thread I'm looking to upgrade from the CM9's to the CM10's and have learnt a lot with regards to amplifier requirements for both speakers. If you have a look at the specs for both the CM9's and CM10's on the Bowers and Wilkins website the differences between both speakers are not that big in terms of spec. However the way they sound when compared with each other might be a different matter as the CM10's have the tweeter on top. Hope this helps :)
 

Blacksabbath25

Well-known member
Sep 20, 2015
309
85
10,970
dakchi said:
sound10 said:
Hi dakchi, nice to meet you. I have the CM9 S2"s with the Marantz PM8005 and they make a fantastic combination. Plenty of power and current to drive the CM9's really well. With regards to needing a power amplifier to drive these speakers well I don't think that is necessary at all imho. From looking at the Cambridge Audio amplifier specs I can't see any reason why the amp would have any issues driving the CM9's unless you like to listen at extremely high volume levels or you have a massive room to fill with sound. Just to add that Marantz and Rotel amplifiers go well with Bowers & Wilkins. Perhaps Cambridge Audio products don't and that is where the issue could be. Just to add the Marantz PM8005 is now just under 600.00. That is a fantastic price and will work very well with your CM9's. Hope this helps :)
Hi sound10,

Thank you for your response. Actually, the Cambridge goes very well with the CM9 and I get very nice musicality. However, I hear everywhere that the CM9 will perform better with powerful amp with high current. I am happy with what I hear now, but if it is worth is, I can add a power amp or even change the Cambridge if there will be a significant improvment. I haven't tried the CM9 with more powerful amp to judge. Maybe I don't have to listen to what people say, as long as I'm happy with what I get. It's my constant search for perfection *fool*
if your happy with the Cambridge and the cm9 sound what's the point in wasting money on a power amp it's still going to sound the same .

what are you trying to improve on sound wise then what do you not like about your setup ?
 

dakchi

New member
Apr 9, 2011
18
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0
sound10 said:
Just to add like other forum members have already said, rated watts per channel of an amplifier is only one part of whether an amplifier will drive a speaker well. What is equally important are the quality of components inside the amplifier especially the quality of the power supply and it's ability to deliver clean and high current as and when it is needed. Another factor is what headroom the amplifier has when it hits a certain load. As previously mentioned by myself on another thread I'm looking to upgrade from the CM9's to the CM10's and have learnt a lot with regards to amplifier requirements for both speakers. If you have a look at the specs for both the CM9's and CM10's on the Bowers and Wilkins website the differences between both speakers are not that big in terms of spec. However the way they sound when compared with each other might be a different matter as the CM10's have the tweeter on top. Hope this helps :)
Thanks again for the response. I do understand that the quality of the power supply is important. However, since this is not something you can find in amp specs, I was wondering if there are measures that I have to consider when choosing an amp. For example, I know that if I have to fill a large room, I need the output of the amp (watts) to be as big as possible. This is something tangible. Hope you understand
 

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