hypex power ratings

[davidr3032]

The Quad 909 delivers 140 watt ch rms into 8 Ohm and 225 watts rms into 4 Ohm, which is a pretty decent score in my book. The manual should give a graph of output for a range of impedance loads.
I use a virtually identical (refurbished) Quad 606-2 driving Quad 2805s (plus sub). I think the 606-2 (and by implication the 909) is an excellent amplifier without any sonic signature. It has been impossible to identify far lesser amplifiers in double blind tests. If you think you may not have enough power you could, if you have not already done so, use a high pass filter on the main amplifier and speakers to take some of the heavy lifting away from the 909 and the Maggies and make your sub do a bit more of that hard work.
Since much of the power is needed for the lowest frequencies, relieving the main amp and speakers of that job really works. So you may even consider adding a second active subwoofer for more bass power, and of course also a smoother in-room response. Adding some kind of dsp room eq will also give a much tighter and realistic bass - I have been very pleased with a simple Antimode 8033 dsp unit for the sub(s).

Thanks for the advice. Yes I have been considering bi amping. But I didn't consider your more simple solution. I will give that a go. What do you use for the high pass filter? I've often wondered if professional high pass filters and crossovers units are just as good as dedicated hifi ones which tend to be very expensive. Being a music producer myself I wouldn't think twice about sending an entire mix through a dbx unit for example. Yet in the audiophile hifi world that may be frowned upon

 

[EdW]

Thanks for the advice. Yes I have been considering bi amping. But I didn't consider your more simple solution. I will give that a go. What do you use for the high pass filter? I've often wondered if professional high pass filters and crossovers units are just as good as dedicated hifi ones which tend to be very expensive. Being a music producer myself I wouldn't think twice about sending an entire mix through a dbx unit for example. Yet in the audiophile hifi world that may be frowned upon

SVS 16 Ultra (SB16 rather than PB16 is best for music) could be a good match as a sub. It includes a x-over for your power amp for your main speaker(s). More expensive would be a digital x-over and DSP such as miniDSP SHD to separately feed the power amp to the main speaker(s) and the sub(s)

 

[Willem]

I use a passive high pass filter such as the Harrison Labs fmods, but in a custom cable.

 

[davidr3032]

Thanks for the advice everyone. But I'm still none the wiser when it comes to the power ratings of these hypex based amplifiers. As someone pointed out the maximum power rating for amps recommended by Magnepan for my speakers is 200w. So for example are the nord nc1200 based amps roughly equivalent to a 200w amp?

This is a big problem with these misleading specs put out by sellers of amps with hypex modules. You have to guess what the actual power rating of the amp is and in doing so may get it wrong and run a risk of damaging your speakers. The magnepans have very delicate ribbons. So its possible that an amp with too much power could damage them. As well as continually blowing the speaker fuses

 

[EdW]

Thanks for the advice everyone. But I'm still none the wiser when it comes to the power ratings of these hypex based amplifiers. As someone pointed out the maximum power rating for amps recommended by Magnepan for my speakers is 200w. So for example are the nord nc1200 based amps roughly equivalent to a 200w amp?

This is a big problem with these misleading specs put out by sellers of amps with hypex modules. You have to guess what the actual power rating of the amp is and in doing so may get it wrong and run a risk of damaging your speakers. The magnepans have very delicate ribbons. So its possible that an amp with too much power could damage them. As well as continually blowing the speaker fuses

The Hypex modules specs are a little over egged in the literature but you can get the measured data from Hypex which is in broad agreement with @amirm measurements. Amir’s measurements can be carefully examined and all professional engineers on this forum believe that they are sound. A caveat is of course that another manufacturer may choose to build a Hypex amp with substandard power components or heat sinking or even breaching safety standards. If you go cheap buying an amplifier then caveat emptor!
Specifically, from Hypex data, the NC1200 can deliver ~520W into 4 Ohm <0.1% THD. Unfortunately I haven’t seen any measurements from Amir’s on this amp. 520W/4 Ohm corresponds to 45.6V rms. This is about 24dB above the 86dB spl at 2.83V (magnepan 3.5 sensitivity) - so about 110dB spl out of your speakers at 1m. Room acoustics and listening position will change this figure for you of course.

https://www.hypex.nl/img/upload/doc/ncore/nc1200/Documentation/NC1200_datasheet_R10.pdf

The greatest risk to a speaker when driven from a correctly functioning amplifier is the amplifier clipping. A lower power amp will clip at a lower level. Clipping produces a spread of harmonics with significant power which can damage the tweeter. Your bass driver may be rated at 200W but your tweeter is most decidedly not! If you cannot hear distortion, and in particular clipping (which is quite unpleasant) then you are probably not damaging your speakers. You could of course be damaging your ears but that’s another story.

 

[March Audio]

Yes I have read the review of the nc500 already. And I was still confused as to what its power rating was. The only reason I mention 8ohm is thats the standard way hifi amps power is measured. So if an amp says its 200 watts or whatever, that's what it means. It means 200w rms into 8hm 20Hz to 20kHz. It doesn't mean its 200 watts with the measurement methods changed. Like using 1kz rather than the full frequency spectrum etc. If manufacturers start messing around with specs like this then no one will know where they are. You've got an amp and you want to try a more powerful one and you have to go through data sheets and graphs then have to ask people on a forum to try to work out if an amp is more powerful than the one you already have. And no one is quite sure anyway. Its a bit of a pain. That's why they should have standardised measurement methods. You can include all the graphs and extra info if you like as well. But use standardised methods for the basic amp info.

Of course I should be concentrating on how an amp performs into 4ohms as well as below that. That's the most important specs for my speakers. I'm just annoyed at hypex and companies like Nord that give misleading specs. I'm sure most people who see 200w beside an amp on a website assume its more powerful than an amp on another website that says 140w beside it. Turns out that's not always the case

I'm guessing the nc500 is around 250 watts using standard measurement methods. But I'm just guessing. So that sounds like it might be the way to go to drive the Maggies nicely

Hypex don't give misleading specs and perform as advertised. There is no "standard", you need to look at and understand the stated test conditions. Hypex provide far more performance info than most

Please note that Amir doesn't measure power output a a consistent distortion level in his tests. It varies from review to review so when comparing with the manufacturers spec you need to take this into account and do so at the same conditions.

 

[davidr3032]

Hypex don't give misleading specs and perform as advertised. There is no "standard", you need to look at and understand the stated test conditions. Hypex provide far more performance info than most

Please note that Amir doesn't measure power output a a standard/consistent distortion level in his tests. It varies from review to review so when comparing with the manufacturers spec you need to take this into account and do so at the same conditions.

Hi March Audio i see from your website you sell a hypex nc1200 amp called the p701. As stated on your website -

P701 TECHNICAL SPECIFICATIONS
Power Output
2 Ohms - 1200 W rms
4 Ohms - 700 W rms
8 Ohms - 400 W rms

You seem to have taken the hypex figures for peak power and then just written the letters rms afterwards. Or am I missing something here?

 

[davidr3032]

The Hypex modules specs are a little over egged in the literature but you can get the measured data from Hypex which is in broad agreement with @amirm measurements. Amir’s measurements can be carefully examined and all professional engineers on this forum believe that they are sound. A caveat is of course that another manufacturer may choose to build a Hypex amp with substandard power components or heat sinking or even breaching safety standards. If you go cheap buying an amplifier then caveat emptor!
Specifically, from Hypex data, the NC1200 can deliver ~520W into 4 Ohm <0.1% THD. Unfortunately I haven’t seen any measurements from Amir’s on this amp. 520W/4 Ohm corresponds to 45.6V rms. This is about 24dB above the 86dB spl at 2.83V (magnepan 3.5 sensitivity) - so about 110dB spl out of your speakers at 1m. Room acoustics and listening position will change this figure for you of course.

https://www.hypex.nl/img/upload/doc/ncore/nc1200/Documentation/NC1200_datasheet_R10.pdf

The greatest risk to a speaker when driven from a correctly functioning amplifier is the amplifier clipping. A lower power amp will clip at a lower level. Clipping produces a spread of harmonics with significant power which can damage the tweeter. Your bass driver may be rated at 200W but your tweeter is most decidedly not! If you cannot hear distortion, and in particular clipping (which is quite unpleasant) then you are probably not damaging your speakers. You could of course be damaging your ears but that’s another story.

Thanks thats useful info. So if more power is actually safer for speakers then why do speaker manufacturers give maximum amp power ratings for their speakers?

 

[March Audio]

Hi March Audio i see from your website you sell a hypex nc1200 amp called the p701. As stated on your website -

P701 TECHNICAL SPECIFICATIONS
Power Output
2 Ohms - 1200 W rms
4 Ohms - 700 W rms
8 Ohms - 400 W rms

You seem to have taken the hypex figures for peak power and then just written the letters rms afterwards. Or am I missing something here?

Its not peak power. Its rated at 1% distortion which is a very common level to use.

As has already been mentioned its really average.

RMS has been stated as its a term that customers are familiar with and unfortunately widely (possibly universally) used even if incorrectly applied. Yes I should really update the website to be absolutely technically correct, but 99.99% of visitors wouldnt understand or care about the distinction. Also the number wouldnt change so its hardly misleading.

 

[March Audio]

OK I've just read through the data sheet for the nc500. Its states continuous output power as 100 watts. So now I'm more confused. The main power ratings stated are for peak power at 1% thd. Does this mean an nc500 amp would be really just be a 100 watt amp?

No its 700 watts into 4 ohms.

Now there is a part of the Hypex specs which always creates questions and confusion. In the power ratings it has a "continuous" rating

They are somewhat nebulous about its conditions and meaning. It implies they cant sustain the max power output, but this is not the case. That is dependant upon the efficacy of the module cooling.

Above are the ratings for the NC250 module. Yet you will find Amirs tests show it is not just a "50 watt amp"

Below is a video of a P252 (NC252 module) running at 250watts for 5 mins (similar to the FTC test)

It should also be noted that for music reproduction the average power (RMS ) is not a particularly useful number. Music has a low rms signal level. It typically might be just 1/5th of the peak (music dependant), so its actually more useful to know the burst power if you want to understand how the amp might perform with real music.

No amp will ever run anywhere near its max average (RMS ) power output with music.

 

[pma]

Hi March Audio .....
.
You seem to have taken the hypex figures for peak power and then just written the letters rms afterwards. Or am I missing something here?

..... which is of course wrong, because power is just power. No "rms power" does exist. Yes we use rms voltage or current to calculate power, but it is just the power in W.

https://electronics.stackexchange.c...-calculating-average-power-and-not-simply-the

Some explanation is also here

 

[davidr3032]

Its *not* peak power. Its rated at 1% distortion which is a very common level to use.

As has already been mentioned its really average. RMS has been stated as its a term that customers are familiar with and unfortunately widely used even if incorrectly applied. Yes I should really update the website to be absolutely technically correct, but 99.99% of visitors wouldnt understand or care about the distinction.

View attachment 105571

View attachment 105567

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I guess one man's "i will have to update my website" is another man's "i will have to remove the misleading information from my website"

The reason I assumed these figures are for peak power is because for 4ohm and 8ohm they are the same figures as the nc500 module. Which as stated in its datasheet is for Peak power. (Though the nc1200 has more power into 2ohm)

So the datasheet for the nc500 states Peak power output - 1%thd 400w 8hm and 700w 4ohm
The datasheet for the nc1200 states
Output power rating - 1%thd 400w 8ohm and 700w 4ohm.

Exactly the same numbers. So if these are *not* both the peak power specs am I to believe that hypex made a much more powerful amp in the nc1200 and didnt let that be known in their specs. And just kept the figures the same as the nc500 by changing the testing parameters. I'm suspicious of this and these terms they are using. I also note that some hypex datasheets quote the power specs as Max power output.

So we have three different terms used in the hypex datasheets -

Peak output power
Max output power
And
Output power rating

At best using inconsistent terminology or inconsistent power rating methods is confusing. At worst its just plain misleading. Especially if amp makers go on to use these figures in their amps stating that they are rms power or just happen to omit that they are for peak power or max power or for 1% thd rather than 0.1%thd or 1khz rather than 20hz-20kHz etc etc

So surely either the terms mean the same thing or the specs are actually different and the nc500 and nc 1200 modules have considerably different power ratings? Since the peak power rating will give much higher results

 

[Matias]

@davidr3032 Power is proportional do heat dissipation. Short bursts of a few seconds is known peak power. Continuos power of 5 minutes (which follows FTC rules) still is the full 500W RMS rating. Only if it you leave the amplifier on full power for hours than maybe the amp overheats and starts limiting its power output. That is, if you don't add extra heatsinks or fans.

This applies for all amplifiers by the way, class A and AB as well. It's just that these usually have large heatsinks because they are inefficient, and class D avoids it for short burst and continuos few minutes of power, which are regular use cases for music or movies, and not hours on max power which is an unrealistic test use.

 

[pma]

RMS power is a wrong term and it is just a nonsense.

 

[tmtomh]

Hypex gives substantially more performance information than most other manufacturers including Quad.

For example as far as I can tell from the manual the Quad 909 has the following power ratings.

140W into 8 ohm (0.05% THD)
250W into 4 ohm (0.05% THD)
100W into 8 ohm (0.01% THD, 20Hz-20 kHz)

OK, how does the THD change with power level? Is it higher at lower power levels? How does it change with frequency? We do not know because they give us limited information.

Compare this to Hypex which gives you plots of THD+N vs power level for 3 frequencies (100Hz, 1 kHz, 6 kHz).

All power levels discussed so far are AVERAGE power which is calculated using RMS voltage, RMS power is an often misused term and has no meaning. I will agree that the Hypex data sheet tables are not the greatest in terms of how they summarize performance but it is all there for you to see in the plots. Also because Hypex sells modules (not completed amps) you have the additional variables of how will the module be heatsinked and what power supply will be used (not an issue with the Hypex MP amps). However, given all this Hypex still gives you tons more information to evaluate performance.

Looking at the NC400 datasheet at I would put the NC400 power ratings as follows.

300 W into 4 ohm (0.05% THD+N)
150 W into 8 ohm (0.05% THD+N) - datasheet does not show power in to 8 ohm but halving power in to 4 ohm should be close

For the NC1200.

500 W into 4 ohm (0.05% THD+N)
290 W into 8 ohm (0.05% THD+N)

So the NC1200 would provide double the power compared to what you currently have and NC400 would be about the same.

Michael

Thanks for this!

Re the part I have bolded above, this is the one (and IMHO only) issue with Hypex (and Purifi) power specs: the "top line" power number, which is usually also encoded into each module's model number, describes power into 4 ohms rather than 8 ohms, and at a THD level that is fine but well above the lower THD numbers the module can produce at normal listening volumes, and for which the modules are touted.

It's not a big deal IMHO, although it does mean we have to read endless long posts from @restorer-john about how all modern-day manufacturers are charlatans. (I kid, I kid!)

 

[davidr3032]

RMS power is a wrong term and it is just a nonsense.

Few would disagree. However the answer for amp manufacturers to this is to petition the powers that be that govern standardised methods of testing and to get them to change it. While still letting everyone know the power rating of your amp meantime. You can also include all the extra specs you like in the datasheets stating how great it performs with other parameters. Without a standardised ratings people like me wont know if they are buying a more power amp than what they have or if its safe to use it with their speakers

 

[NTK]

... However the answer for amp manufacturers to this is to petition the powers that be that govern standardised methods of testing and to get them to change it. ...

We are in luck! FTC is considering revisions to the amplifier power output rating standard (16 CFR Part 432). They are soliciting public comments until 16 Feb 2021 (6 comments so far). The last revision was in 2000/2001. This is a once in 20 years opportunity.
https://www.federalregister.gov/doc...for-amplifiers-utilized-in-home-entertainment

 

[MrPeabody]

I own a pair of magnepan 3.5's which are being powered by a quad 909. The word online is that these speakers sound much better with higher powered amps than what I'm currently using....

To learn whether the word online is likely to be accurate, you should try to get a sense of whether the speakers sound fine at low to moderate volume but then at higher volume you sense the presence of distortion that would indicate that the amplifier is clipping. In this case, a more powerful amplifier would in all likelihood reduce the occurrence and severity of clipping, thereby reducing distortion. It is a popular misconception that (irrespective of whether clipping is occurring with the less capable amplifier) a more power amplifier that is capable of supplying greater current and power will improve the sound of speakers. This can be true in specific cases, but it isn't something that is true in the general sense. When it is true, the only reason it would be is that the distortion level for the weaker amplifier (when it isn't driven to clipping) is above the threshold of audibility. You will encounter varying opinions on this, but I will just say that there are very good reasons why lots of experienced and knowledgeable audio types say that with just about any well designed amplifier, the amplifier's distortion will not be audible unless the amplifier is driven to clipping. Even if it happens that the amplifier's distortion is audible routinely, i.e., when it isn't clipping, this amount of distortion would in all reasonable likelihood be so minuscule in comparison to the distortion from the speakers (any speakers) that you'd find it nearly impossible to notice the distortion caused by the amplifier. Ideally you should try to develop a sense of whether the amplifier you are using presently is clipping or whether the distortion it generates when not clipping is at a level high enough for you to notice it as an incremental distortion overlaying the speaker distortion. In either case, the only reason it would be sensible to think that this has anything to do with any particular pair of speakers would be if those speakers were unusually low in sensitivity such that you needed to turn the amplifier up to a higher output level compared to what it would be with a more typical pair of speakers. As a general rule, the sensitivity of a loudspeaker obeys an inverse relationship (approximately) with the speaker's impedance. Unless the speakers you are using have unusually high impedance which would require you to turn the amplifier up to a higher output level, there wouldn't be any reason to associate the amplifier issues with the particular speakers you are using. If you decide that the amplifier is likely clipping (you hear distortion at high volume that you don't hear at low volume and you are certain that it isn't the speakers), then it might be indicated to look for a more powerful amplifier. In the case that you would decide that the amplifier is routinely generating distortion that you hear overlaying the speaker distortion (and you are certain that it isn't the speakers), then it would be indicated to look for a cleaner amplifier, which might also be a more powerful amplifier, but not necessarily so.

 

[MrPeabody]

...The below quote is copy pasted from their web site FAQ section:

“...An Gold Standard for an amplifier would be to double the power at 4 ohms. This concept is important even if you are buying an 8 ohm speaker. If the amplifier is rated at 80 watts at 8 ohms, it should (ideally) produce 160 watts at 4 ohms (or close to it). None of the receivers will do that. However, this is the benchmark of a good amplifier design. A 10 watt amplifier that produces 20 watts at 4 ohms "speaks volumes" about the PHILOSOPHY of the designer. (But, of course, it does not tell you if a 10 watt amplifier is enough for your room.) In the final analysis, buy an amplifier that comes as close to doubling the power at 4 ohms as your budget will allow.”

https://www.magnepan.com/faq#power

The above guidance from Maggie seems to confirm my above assumption about doubling of Watts when halving Ohms. So you should be shopping for Amps rated @ 4 Ohms at between 200 Watts to 400 Watts.

In accordance with Ohm's law, there are only a few ways in which it would be possible for amplifier to not deliver twice as much power into 4 Ohms as it delivers into 8 Ohms. Since current would double, power would double. For this not to occur, the output voltage (relative to a given input voltage) would have to be less with the 4-Ohm speaker than with the 8-Ohm speaker. This would occur if the amplifier had circuity that automatically lowered the gain in response to a load impedance for which the current would be great enough to cause the amplifier to overheat. Since most speakers nowadays seem to have nominal impedance at 4 Ohms or thereabouts, it is obviously better for any amplifier to easily tolerate the amount of heat generated when driving a 4-Ohm speaker to a high volume level. But there is no amplifier that does not have some limit on the amount of current it can tolerate. As such I do not think it is generally a bad thing for an amplifier to sense the load impedance and automatically adjust the gain.

 

[AdamG]

In accordance with Ohm's law, there are only a few ways in which it would be possible for amplifier to not deliver twice as much power into 4 Ohms as it delivers into 8 Ohms. Since current would double, power would double. For this not to occur, the output voltage (relative to a given input voltage) would have to be less with the 4-Ohm speaker than with the 8-Ohm speaker. This would occur if the amplifier had circuity that automatically lowered the gain in response to a load impedance for which the current would be great enough to cause the amplifier to overheat. Since most speakers nowadays seem to have nominal impedance at 4 Ohms or thereabouts, it is obviously better for any amplifier to easily tolerate the amount of heat generated when driving a 4-Ohm speaker to a high volume level. But there is no amplifier that does not have some limit on the amount of current it can tolerate. As such I do not think it is generally a bad thing for an amplifier to sense the load impedance and automatically adjust the gain.

? exactly what is your point in regards to what I was describing/clarifying for the OP about his specific speakers and what the OEM recommend power numbers are?