Too Much Power?

I have a question that relates to the maximum power output of new Bel Canto Ref 600M monoblocks, which I am considering to replace the Audio Research 150.2 SS amp I am currently using in my main system. (Yes I am another of the "lunatic fringe" who enjoys the results of good quality Class D.)

The Ref 600Ms are  based on a Hypex Ncore module, and are stated to produce a maximum power output each of 300W into 8 ohms.  My question  is whether this can prove to be a problem in powering my Focal Alto Utopia Be speakers, which are stated to have a "maximum" power handling capacity of 250W each (their nominal impedance being 8 ohms).

I listen to mostly classical instrumental and vocal music and other acoustic instrumental music, and do not listen at particularly loud levels:  the ARC 150.2 is rated at 150W per channel into 8 ohms and it has never in 10 years appeared to go even close to its limits; I rarely if ever  turn up the volume control on my ARC LS-25 past the 11:00 o'clock position.

Should I be concerned about the Bel Cantos damaging the Utopias, given the speakers' 250W per channel maximum capacity and the 300W per channel output potential of these amps?  The Be tweeter and other components of these speakers can be very expensive to have to repair, not to mention the inconvenience and aggravation which I really do not need. 

Thanks in  advance for any thoughts or advice on this.


but feel free to send them to me
You really never have to worry about too much power. Thats what the volume control is for. If you push a speaker too hard, it's very easy to hear.
I agree with sfall. I mean, I have seen a strong amp (Boulder) over-drive small 2 way speakers (YG Carmel 1’s), but the Carmel 1’s are not true full range speakers. I’d recommend picking up a reasonably accurate DB meter to monitor DB levels. You can even download paid Iphone apps which will do a decent job. That is cheap insurance for your speakers & ears.

Hah, putting a Boulder against a small 2-way is almost like plugging your main speakers straight in the 120V wall A/C! lol.

That being said, I’m sure this has been stated many times before, but it is always better to have an amp more powerful than what the speaker needs rather than having an amp under-powered. With under-powered amps, you are more at risk for things such as burning out the tweeters because the amplifier is clipping (i.e. sending DC to the speaker) during large transient signals such as bass. Also, with the larger power supply in your Ref 600’s, you’ll be able to get better/quicker transient (such as bass hits).

BTW, I’m running 1,000 watt monoblocks to my 6-1/2" B&W 805D2 speakers and never had a problem! Everything comes across clean, strong and crystal clear!

Auxinput, Agreed re: the dangers of under-powering speakers, especially power hungry speakers like my old Infinity Ren 90’s which had the Watkins dvc woofers. I’ve seen more than one vintage pair show up on Ebay with burnt aluminium traces (a tell tale sign of fried tweeters).
Your Focal’s have a wicked impedance 3ohms at two power hungry points 80hz and 500hz, and a real bad -phase angle at 60hz which could equate a EPDR of 2ohms. Which is not real good good for a Class-D amp if you like to pump it up a little.
I think a Krell/D’agostino type amp, with great current ability would be best for these in these bass power hungry regions.

Cheers George

The real enemy of any speaker is not too much power but distortion and clipping. The Focal Alto Utopia Be speakers have a rated maximum input rating of 250 watts but can handle significantly more as long as it’s clean power. My older 4 ohm Magnepan 2.7qr speakers have a rated max. power input rating of 300 watts into 8 ohms. I’ve driven them for almost 2 yrs with class D monos rated at 600 watts into 8 ohms and 1,200 watts into 4 ohms. They’re the best amps I’ve ever used on them thus far and I’ve become a big fan of class D amps due to my experiences using 3 different brands (classDaudio, D-Sonic and Emerald Physics).
The Bel Canto Ref 600M mono-blocks, at 300 watts into 8 ohms, will drive your speakers very well and the possibility of them damaging your speakers is close to zero. This is because these amps have extraordinarily low distortion levels (.0003%) and your ears would begin bleeding from the high decibel level before these amps will be driven into clipping. Class D amps have become well known for their capacity to deliver large amounts of clean power to virtually any impedance, even into difficult to drive very low impedance speakers that have impedance curves that dip down to near electrical short range (down to a minimum 2 ohms for the Bel Canto Ref 600).
With the extra power and class D operation, I think the Bel Canto 600Ms will deliver a very neutral and effortless sound quality with improved bass response, a greater dynamic range and increased detail. I think you’ll also notice an extremely low noise floor and a very smooth mid-range and treble that avoids harshness and brightness.

The better current class D amps deliver near reference level performance at relatively inexpensive prices. Only downside I can even think of is they may take a few hundred hours to fully break-in.

I ran my Altos with MX-R monos which are rated for 300W and double down into 4 and 2 ohms.  Never had an issue.  You'll be fine.
I'm also running 250/500 watt into 8/4 ohms class D monos and my speakers are rated to 250 watts and have a nominal impedance of 4 ohms. So the amps are double what the speakers are rated. I've never had an issue

Thank you to everyone who responded; the comments are really helpful and have allayed any concerns I might have had about the power issue. 

P.S. to Randy-11:  If I do ever need to send them anywhere, you are at the top of the list :)

Yes, it is usually underpower that damages speakers.  Clipping produces a lot of high frequency energy that damages tweeters.  Some amps, including mine (class D Icepower) won't even clip (soft clipping).  Perhaps Hypex is the same way.  In addition, you should hear it ahead of time, as sfall stated.
If there's a problem, it's that you will be paying for a lot more power than you will ever need. Manufacturers love to make you think that more power is better HI FI. This simply is not true. Some of the best systems are powered by no more that 10 to 20 Watts. Quality is much more important than quantity unless it's to impress those who don't know any better.
Ah, but lots of headroom can help a system sound clear and tight..

A lot depends on desired listening levels too. 
One need not worry about too much power, however can purchase too much power. 

Congrats about your new Bel Canto REF600 monos!

I am quite familiar with amps based on NCore technology, owning a pair of NC1200-based Rowland M925s, and having also had in my system and written about the excellent NC1200-based Merril Veritas monos and the NC500-based Merrill Teranis stereo.

Like most everyone already said, you should not be concerned about too much power from the amps.... clipping is the biggest danger, and the significant power reserve in the 27A per side should avoid it, unless the house cat started to play with the volume knob on your preamp *Grins!*

Nor am I concerned about REF600 not being able to handle speakers with low or variable impedance: REF600 has a damping factor of 1000, and should be able to power the majority of speakers on the market today without breaking a sweat.

Be patient with break-in.... Right out of the box, NCore amps are listenable, if less than delightful, but after 48 hours of making music they become quite reasonable. Full break-in should range between 600 hours and just over 1000 hours of chewing some signal. Expect some wildish fluctuations in performance during the first several hundred hours... Nothing to worry about: eventually, any bandwith limitations, excessive brightness, darkness, hardness, transient limitations, etc... all disappear, and the amps will bring you their magic.

You can leave the amps on 24/7 unless the weather forecast promises thunderstorm.... Power draw on idle is minimal... Power efficiency is between 85% and 95%, so even during full operations, the amp will be only moderately warm to the touch... And you will hardly notice their existance on your monthly electric bills.

To speed up break-in, feed them white noise when you are not listening to music, even during night time.... I use an old FM tuner tuned to interstation FM hash, with the preamp volume knob at lowish volume.

As far as I know, REF600 are based on the NC500 module, which is a slightly simplified version of NCore, delivering approximately two thirds of the current of the full NC1200 module. It is unlikely that after break-in is complete you will still experience any anomalies in the form of slight haze, bloat, or mild hardness at high SPL. But if you did, it would be a symptom of the modules approaching saturation. If this happens, change their gain from the factory default of 27dB to the 33dB by operating the setting inside the chassis... I had to do something similar with Merrill Veritas to get best results on my relatively large and demanding Vienna Die Muzik speakers.

You can download the REF600 manual from the page below:

Saluti, Guido

Guido: Thanks for the usefull tips on break-in and related issues. I have observed that you have a lot of knowledge about and experience with quality Class D.

One further thing that occurs to me is if you have any thoughts in how the Bel Canto Ref 600M compares to the Merrill Thors.

My current plan is to do a final audition at the dealer’s in early April, and if that goes well to then buy the amps.

The actual amount of power being used is much smaller than you might think if your speakers are relatively efficient. Having reserve power for gigantic crescendos or that DJ Bass thing the kids like is fine, but I think the general quality and specific tone generated by an amp is where the mojo is, and buying extra watts can be a waste. I have a friend who owns a pair of mondo Pass Labs amps and damn if that V.U. needle ever moves. Great amps anyway…in a interview with Nelson Pass it was noted that during listening to one of his First Watt things that was hooked up to some sort of output metering device, the interviewer noted the amp barely did more than a few watts at fairly loud levels. I like that sort of thing.

Hi Northernfox, as far as I know, the Merrill Thor monos are based on a form of Hypex UCD module, which from an architecture point of view sits below NCore.

Having said the above, the power conversion module is but one factor in the performance of a class D amp.

I have had no experience on Thor at all.... But if you have the opportunity, it might be worth while listening to them. You might want to contact Merrill and see if he can send you a pair to audition in your system.

BTW, what is your allocated budget for this amp project?

Saluti, Guido



Giudo:  With Bel Canto Ref 600Ms ( or with Merrill Thors) I am looking at around $4,500-$5,000 stated price per pair.  I did briefly consider Merrill Veritas;  but at the stated price of $12,000 per pair, I really doubt Veritas would provide enough upside difference for my situation to justify over  double the cost.  

Hi northernfox,

     At your budget you also may want to consider the D-Sonic M3-1500-M mono-blocks.  Here's a rave review from 6Moons of the M2-1500-M which are the exact same amps as the M3 per D-Sonic owner Dennis Deacon.

     The power may not be needed given your speakers but they also offer the M3-600-M which are 600/1,200 watts at 8/4 ohms.  I own a pair of these and they're the best amps I've ever used on my older Magnepan 2.7qr speakers that are 4 ohms.

     Here's a comparison

M3-1500-M  ($1,375 each, $2,750/pr) 1,500 watts into 8 ohms

M3-600-M  ($1,075 each, $2,150/pr)   600 watts into 8 ohms

Both offer 3 week in-home trials.

Here's their website:

Sorry, never heard the Bel Canto Ref 600 or the Merrill Thors so I can't compare to the D-Sonics.  I do know the D-Sonics are high-end performance at reasonable prices.

Good luck,
As I tried to outlined in my first post Steve, with these Utopia Be speakers, you need current more that watts, as they are 92db efficient 100watts at 8ohm will do.
But with that 2 ohms and 3ohms in the bass you need current, so when it hits those loads you will have close to 400watts available, if you pick the right amp, KRELL like power, look for amps that almost double their 8ohm wattage  to 4ohms and double again down to 2ohms

Cheers George
Most people have no idea about the properties of an amp, source, cable, loudspeaker etc.

This is essential to understand why the stage and sound is what you hear.

Your ’older’ speakers are able to create a deep and wide stage. need an amp and source who can do the same.

The Bel Canto is not an amp what can build a deep and wide stage. I would never go for an amp like this. Not even for free. I would never give my clients this advice.

3-dimensional sound is the most exiting part in audio to create an addictive stage.

I would go for a Pass or for an older Krell amp. You will get all the properties you need. Audio Research their amps are inferior to the ones I just mentioned. Based on their properties they are incomplete.

In my world Audio Research is not a highend brand. For a high level in highend you need a wider and deeper stage. When we audition AR amps they never are able to create the stunning level Pass labs can give you.

The have more a sound than diversity in sound. Diversity is the most important part to create emotion for us human beings. The Pass shows more layers in sound. This is very important for the emotion and realism in sound.

Hi Northernfox, one option, somewhat less expensive than Veritas, are the Theta Prometheus monos. Like Veritas they are based on the full NCore NC1200 modules, but instead of the NC1200/700 SMPS, Theta has designed its own power supply... I believe it be a toroidal design. Unless things have changed, Prometheus may be priced at $9K / pair.

I have not tried them... Given the different power supply design, they are bound to sound a little different from Veritas, but I do not know if I would necessarily prefer one over the other.

Saluti, G.

BO said...


Most people have no idea about the properties of an amp, source, cable, loudspeaker etc." 

I am not sure what "most people" know about the above.... I only know what I have experienced in some 60 years of making and listening to acoustic music... Live and recorded alike.

In the last few years, I gradually formed a more than positive opinion of certain class D amp designs, particularly those based on NCore, Pascal M-Pro2, and even some classic ICEpower. In particular, I have experienced the staging, imaging, and timbral resolution and emotional engagement of NCore to be exceptional.

Have I listened to Pass and Krell? Sure, many times.... Really nice amps... Yet this far I have prefered the aforementioned NCore and Pascal based amps.... But I keep an open mind... The future is, of course -- in the oft unpredictable hands of Gaia *Grins!*



Go for it. Having lots of power means you can hear yr stereo clean at low volumes & you will be surprised how recordings you once did not rate sound much much better. 
Sfall nailed it.  Never worry about too much power.  It is not having enough that kills speakers.

Use the volume control to smoothly deliver the power and your ears will tell you when your speakers are at their limits.
Some may consider my present situation off the subject, but then again it may not be.  I am driving an Stax SR5 electrostatic pair of headphones with a 160watt per channel Rega Osiris integrated amplifier.  I am using a Stax SRD6 energizer box.  I have found over the years that the Stax's own amplifiers, whether solid state or tube to not have enough power to adequatly run rock and roll.  That is a fact, which is the main failure of using an entire Stax system.  I have previously used a 50 watt per channel Audio Research integrated amplifier, but again, for rock and roll the 160 watts on my Rega is overall the best combination.  Again, even for Stax headphones, evrything else being equal, more power is better.  And it is much easier to damage a Stax electrostatic headphone using an underpowered amplifier than one with "too much power".  And finally, I can turn the volume up to a much higher level with more power dur to the fact that, using true quality electronics, the amount of distortion goes way, way down.  Yes, it is distortion itself which is the main factor in damaging a speaker system.  Yes, either regular speakers, or Stax headphones.
In my world it is not about how it is build or which kind of system it uses. No it is all about what you can hear.

Like Guidocorona says: when an amp can reveal all the layers/diversity in sound and combined with a deep and wide stage with an intimate physical stage this is what you need and want.

Like more power wil give you always more control and grip. It is never a negative thing, so no worries about it.

In the beginning I prefered Pass XA amps, but based on my insight and knowledge these days I can create a higher level with an X series amp.

This is also based on the fact it has more power. I can reveal more details in the high freq. with it. I can create the same sound of a XA amp out of a X series amp. But I add it with more control/grip and details in the high freq.

You need to understand the properties to create the benefit with the X series over the XA series. Properties will always be important to understand the sound and stage. And to use it maximum.

I work by Tru-Fi, which are 8 parameters you judge sound for. When you listen to Pass labs pre/power combination you will hwar by Tru-Fi that it is incomplete/

This means that a part or more parts of Tru-Fi are missing. So what is missing?

instruments and voices are in real very small and direct. Almost all shows and in shops you see that instrumentd and voices are too big in proportion. Beside this the black level is nog that good. 

When you would use a pre amp what can create an intimate and realistic individual focus you will experience the music at a more emotional level.

At the end you need all the different aspects/properties  of sound what can be revealed when it is complete.

I have turned an aesthetic corner having realized that bo1972's incomprehensible comments are actually True Art, and after criticizing him for this stuff, I now relish each post as they contain gems like this: "At the end you need all the different aspects/properties of sound what can be revealed when it is complete." Wonderful stuff.
Thanks wolf_garcia

Soon you will hear the sound where I was talking about many years ago. Because we reached a level what will help many people to a much higher level in quality what is possible at this moment.

Audio needs to be created how music sounds in real. And then you need all the different aspects of how sound is being created.

But most systems show that they are incomplete. Each incomplete system always will have a lower level in realism and emotion.

The problem is that the way audio is being selected by trial and error always will be like a big gamble.

When you have no idea what all the different properties of each part of your system are you will never understand why the stage and sound is what you hear.

I learned to extract the full DNA of each single part. I was that focussed to understand why the stage and sound is what I hear.

Tru-Fi has nothing to do with personal tatste, it is based on all parameters which you can hear in sound.

That made it possible to create a higher level in realism and emotion. When I said; I have done thousands of tests, it is exactly as what I wrote. And I still do a lot of testing. It is the way how I work with music and audio. It is a natural way for me of creating sound as natural as possible.

At the end I do it so more people will enjoy music as my clients and I do. You want others to feel the same level of exitement and emotion.

The good thing is that even for prices many people can afford it can be created. In the last 2 years I had the freedom and options to do a lot of research. And now it is time to share it so many people will have a stunning sound for normal prices.
wolf garcia,

    Sarcasm, as deployed by yourself, can be such an effective tool at illuminating nonsense.

Wonderful stuff, indeed.
Post removed 
I am very sarcastic to all the F. losers in the world of audio. And yess there are many and this is a fact no one can change.

The reason why I am so sarcastic to these extreme limited people in audio is based on the fact that they don’t take audio and their job serious.

... I will never take them serious. It is a 100% fact that they do not add anything in my world.

The only thing they do is creating a low level in quality and realism. And this needs to stop ...

... they were F. lazy and greedy and they did not add anything possitive to the world of audio.

These day we (clients and other people who work in audio) go to audio shows to see who is the biggest loser of the show. And this is no joke. On monday when I talk with distributers we talk about the born losers of the show.

... They are the ones who are blind and limit customers to get value for money.
Wow, Bo, why so angry?
And, given your anger and disdain for those of us here, why do you bother to participate?
When you have met several people who are screwed by different audio companies I understand the feelings of these people.

Audio is very personal and I have seen people being depressed by the sound they had. They had any reason to be upset. It is caused by the lack of knowledge and missing true dedication in audio of those people who work in audio for their personal benefit.

I love music and audio and I do this with full dedication and passion. This is a thing what is not common anymore. I could not do it on the way most people do it.

I want people to be treaten as a human being and not as a number. People need to learn to have respect for their clients. I have to agree that it is difficult for me to be nice to the people who screw their clienst which I met.

When audio is only business for you, you will never become happy with your job. And you never will be able to add anything in this world. I think it would be time for these people to look for another job.

Many people in audio still think it is 1980. They often only sell stereo. And believe cd players are the way to go these days. They did not develope them and never grow with time.

I started to work in audio in 1998 and now in 2017 it is a different world. And there are so much more options and techniques what can create a superior level compared to 1998.

Most people in audio are not able to grow with time and have been stuck all this time. This has a negative influence on people who are interested in audio.

The other negative part is the low quality we see and hear in many products these days. This will also have a negative influence on people who are interested in audio and music.

They way people work and think in audio it will never get better, but worse. When you don’t change there is no way back.

Only doing it differently and more focussed on the needs of people there is a chance it could change.

But when you keep it the way it works now, it only will increase. I think there is nothing to loose. So give people more quality and a honest advice.

He's right…all the "low quality" these days is part of the fact that we're all doomed…"They way people work and think in audio it will never get better, but worse. When you don’t change there is no way back." Personally, I'm taking Bo1972s advice and changing…to something…anything…also, his point regarding employment, "When audio is only business for you, you will never become happy with your job. And you never will be able to add anything in this world. I think it would be time for these people to look for another job." Bo is nothing if not utterly compassionate.
"people being depressed by the sound" of their audio system is a first world problem

I think bo1972 may have been depressing the first world for some time now.

Hi Noble, not sure which World BO1972 may be busy trying to depress, but it isn't my World for sure... Whenever I get a wif of an underappreciated-narcisistic-messianic pronouncement anywhere, and in any human domain, I cringe.

Hi Guido,

     I'm with you, brother.  Life's too short for that stuff.

The truth is hard I know, but you cannot run away from it. 

And when you think everything is fine you are blind and deaf. Confronting is maybe not the nicest way to communicate. When you do nothing, it only will go down.

The youth is not interested in audio anymore, but the main reason is the low quality it offers these days. When I give a demo in a 3D stage they react totally different. And they would love to have something like this.

Quality sells, quantity (and mannnnn we have a lot to offer) does not add anything to the audio market. The audio market is getting smaller each year.

So do you want to hear the truth or the thing you would like to hear?

For the last part it only will give you an illusion. Do you really think you will become happy with it :)

The positive thing in 2017 is that based on techniques it is a lot more easy to create a much higher level in sound quality for less money.

But in real we see and hear that many products does not give you value for money. These products are the ones who are responsible for the decreasing audio market.

The stories of people tell the truth and we listen to them. We don’t run away from it. No we help them to get real value for money.

We see them as humans, not as numbers or cash cows. We live in a world what is getting harder and more greedy each year.

When you would addapt and accept the changing world, you only will loose. So you need to do it differently and learn to look a lot further.

The audiomarket thinks that they can create products consumers needs to buy. What they should have done is listening to the needs of consumers.

And create those products they would like to buy.

Please addend. bo1972 = bs^3

   You stated:" We live in a world what is getting harder and more greedy each year."

     I want to give you a little grammar tip that'll make your posts easier to read and comprehend.  I notice in many of your posts that you frequently state the word 'what' when the proper word to state is 'that'.  See your quote above as an example.  It's disconcerting and results in your actual meaning being harder to grasp.

     Just trying to help you further improve your communication skills so you can more efficiently convey and scintillate us with your words of wisdom.

Thank you,
Thanks Tim, don't forget that english is not my first language. Our website will be in english as well later this year. The text will be rewritten by a pro. 

Even the text in my own language is being rewritten. It is nice to have these people around me :)

Hi bo1972,

     I was thinking English might not be your first language.  I understood your posts and certainly meant no offense. My post was meant simply as constructive feedback to improve your English communication skills.

Thank you,
Post removed 
bo1972 - Please take you off topic discussion someplace else. This looks like a blatant ad for your project.
People with a 2-dimensional system like dtc owns will never like the things I write. That is more based on their personal limitations.

For example: compare any Naim poweramp with a Pass labs poweramp on speakers who are exceptional in a 3 dimenisonal stage and you will understand why the Pass outperforms the Naim.

Only people who have limited knowledge in music are able to buy a Naim amp. When you would be aware how music sounds and that music is never being played in a 2-dimensional stage, you would never buy Naim.

dtc reads things he does not want to read. He is a person who prefers to read the things he likes to hear. He runs away from the truth.

Facts also proof that any 2-dimensional system never will be used a lot after time. Based on our emotion music played by any 2-dimensional system will never be able to create a lot of emotion during listening.

Pass labs is exeptional in diversity in sound. Also during classical acoustic live music the layering in sound is what creates the emotion for the biggest part.

When you use a Naim source and connects it to a 3-dimensional system, the stage depth will be gone for a big part. This proofs the level in stage depth of a Naim source is rather small. And that is why it is a 2-dimensional source.