I built some mono NCx500 amps. They sound great, and they're rated at 700w each @4 ohms. I have quite a few amplifiers, my main and favorite amp is my Plinius SB-301. The Plinius is A/B, with a heavy bias towards A and I believe it's right around 450w/ch @4 ohms.
Both the Hypex and the Plinius do a great job of managing bass, I can't pick a favorite here. I would give the Plinius the edge in the midrange, and possibly also the highs but they're fairly close, I could live with either and be happy.
When I crank the volume, the Plinius amp doesn't ever quit going, it will set my speakers on fire and do it without flinching, and continue to play clean, low distortion music the entire way up the volume ladder.
But the Hypex amps seem to reach a threshold, then quit giving more. They do stay clean all the way up to this threshold and even slightly beyond it. Don't get me wrong, this threshold is intensely loud, louder than you'd play your system if you don't want to end up with hearing damage. But I'm curious why. It seems like if the Plinius is rated at 450w, and the Hypex is 700w, this should be the opposite.
Not necessarily looking to solve a problem, I don't think there is a problem. I'm just curious why.
Both the Hypex and the Plinius do a great job of managing bass, I can't pick a favorite here. I would give the Plinius the edge in the midrange, and possibly also the highs but they're fairly close, I could live with either and be happy.
When I crank the volume, the Plinius amp doesn't ever quit going, it will set my speakers on fire and do it without flinching, and continue to play clean, low distortion music the entire way up the volume ladder.
But the Hypex amps seem to reach a threshold, then quit giving more. They do stay clean all the way up to this threshold and even slightly beyond it. Don't get me wrong, this threshold is intensely loud, louder than you'd play your system if you don't want to end up with hearing damage. But I'm curious why. It seems like if the Plinius is rated at 450w, and the Hypex is 700w, this should be the opposite.
Not necessarily looking to solve a problem, I don't think there is a problem. I'm just curious why.
The 700W@4ohm for the Hypex amplifier is peak power; continuous output power is 100W.
Maybe this puts things in perspective?
Maybe this puts things in perspective?
The only way to be sure is to get a 4 ohm / 200W resistor on a big heatsink and then use a tone generator and oscilloscope to see for yourself. Place the 4 ohms resistor at the end of the speaker cable (to include a bit of real-life speaker cable inductance/capacitance), where the speakers usually reside/are connected, and then see when the clipping occurs.
Maybe NC1200? I think that one would have more power...
Maybe NC1200? I think that one would have more power...
That's the difficult part, the NC1200 technically isn't more power at 4 ohms, it's only more power at 2 ohms. The NCx500 says its 700w @4 ohms, and 700w @ 2 ohms... The NC1200 says it's 700w @4 ohms, and 1200w @2 ohms. It would definitely be interesting to compare them side by side.
More power at 2 ohms means gentler current limiting, i.e. letting more power (current) reach the speakers... could be very important with difficult loads.
I'd look at various options with a cro, as suggested already above...
Class D amps when pushed hard, will change their switching frequency. On top of that, the SMPS will do the same... a double whammy with class D amps, if powered by SMPSs. This can all be measured as well...
The internal wiring will play a big role... I'd solder one end of the speaker cables to the class D module eyelets; and the other end... I think I'd use properly crimped & then soldered lugs/spades, instead of speaker binding posts with screws (done to ensure no solder needed/no soldering required type of assembly). This will bring big perceived sound benefits, especially at high currents.
I'd look at various options with a cro, as suggested already above...
Class D amps when pushed hard, will change their switching frequency. On top of that, the SMPS will do the same... a double whammy with class D amps, if powered by SMPSs. This can all be measured as well...
The internal wiring will play a big role... I'd solder one end of the speaker cables to the class D module eyelets; and the other end... I think I'd use properly crimped & then soldered lugs/spades, instead of speaker binding posts with screws (done to ensure no solder needed/no soldering required type of assembly). This will bring big perceived sound benefits, especially at high currents.
Last edited:
What kind of speaker loads are you presenting to the amps?
What kind of signal are you using? Music?
If so, what kind of music... something with big dynamic range like classical or compressed Umlaut Heavy Metal or 0db dynamic range hip hop?
I figure music with big dynamic range might not show the difference since it will stress the system on peaks, not averages while highly compressed music will compress on average. So the amp with the higher RMS capability will sound louder.
What are the RMS ratings for the NCx500?
Also, how did you configure the gain for the NCx500? How do the gains between the Plinius and NCx500 compare?
https://audioxpress.com/article/fre...-amplifier-module-doubling-down-on-a-flagship
Figure 3: The plot of distortion versus power shows over 340W at 1% THD for an 8Ω load. (1Khz)
Figure 4: With a 4Ω load, maximum power increases to over 700W midband. (1Khz)
You will notice that at 100Hz the distortion is higher and the rated power is marginally lower.
But I'm not sure if these are RMS or peak measurements.
Could it be that the Plinius is simply underrated?
Ultimately it's hard to figure out what you mean by "quit giving more". Have you measured the SPL?
Last edited:
The last 2 dB step there between 450 and 700, when playing music on actual speakers this loud, will not be so easy to to discern really. 2 dB is just a notch louder... so it could be that at this levels, the Plinius is actually starting to spit out quite a bit of distortion - probably 2nd / 3rd so not that harsh, but the Hypex is just singing along undistorted - and this is why you experience that the Plinius continue to get louder but the Hype don't in the same manner...
What say you?
//
What say you?
//
The countinous output means constant sinus wave output and the limit is thermally related.
Do you listens to sinus waves countinously? 😉
I bet the Plinius would fail to give higher countinous output.
As you say, it depends on thermal management.
Current practice is to bold a class D module to the enclosure bottom and that's it.
The Plinius SB-301 is a highly biased class A/B amp with huge cooling capacity.
I bet the Plinius will supply considerably higher continuous output, but I agree it's more a measurement thing.
Current practice is to bold a class D module to the enclosure bottom and that's it.
The Plinius SB-301 is a highly biased class A/B amp with huge cooling capacity.
I bet the Plinius will supply considerably higher continuous output, but I agree it's more a measurement thing.
Wow, so many great replies, thanks!! Not sure where to begin responding because when I originally posted this I had no idea the class D power ratings was such a heated debate (there's a 12 page discussion about this subject on ASR), plus I'm responding from my phone so hopefully this doesn't get totally butchered by fat-fingers and autocorrect haha.
My original goal in building these amps was mainly curiosity. I've used the Hypex DSP plate amps in active speakers in the past and was pleasantly surprised by the output and sound quality. Then a good friend got a pair of Icepower mono amps for his system and I was very surprised at how well those performed.
As mentioned before, I have the Plinius SB-301, which is a beautiful sounding beast of an amplifier that I really find zero flaws in. But, after reading about the low distortion of these Hypex amps, I wanted to build a pair just to see how they compared to my Plinius. I'm not an amplifier builder, I build speakers. I know enough about how amps function to be dangerous, I've rebuilt some A/B amps but I don't own a scope, I did it with some guidance using my decent DVM. I got this Hypex mainly because they're easy, basically plug and play with some soldering, plus having used the plate amps I wanted to know how these performed on a passive speaker.
This next statement will probably trigger some debate, and before I say it, I give my word I'm not a troll, I think this is a good discussion that needs to be had... If you assume the stated power of almost all of these various class D amplifiers are measured in the same way as most class A or A/B amps, you will be seriously disappointed. Knowing that I've never personally measured the output of this specific NCx500, just based on listening to it compared to the Plinius, and based on the fairly obsessive research I've done, I think it would be more realistic to say the Hypex NCx500 is more like 150w @8 ohms, albeit a very clean, low distortion 150w.
Why does any of this matter? If you wanted to design a PA system for a large venue, and you used these (exaggerated) power ratings, you will be very disappointed. Right now, using the speakers I currently have in my system this isn't necessarily an issue- it's a 4 ohm, 9.5" Satori woofer in a 3 way so not necessarily power hungry, it plays very loud with the Hypex amps without much issue. But if I use something like a WMTMW that had a pair of power hungry woofers and I assumed I had 700w, blowing the tweeters when this amplifier clips would be a legitimate concern because there is nowhere in the vicinity of 700w of legitimate power. I think you would need something like the NC2k, which is also grossly exaggerated at 1,600w @8 ohms, it's probably more realistically 410w @4 ohms RMS (RMS power ratings are another debate altogether, but it's what most people understand).
Here's a quote from that 12 page discussion on the ASR forum, I think he nailed it but I'm curious what you guys think.
My original goal in building these amps was mainly curiosity. I've used the Hypex DSP plate amps in active speakers in the past and was pleasantly surprised by the output and sound quality. Then a good friend got a pair of Icepower mono amps for his system and I was very surprised at how well those performed.
As mentioned before, I have the Plinius SB-301, which is a beautiful sounding beast of an amplifier that I really find zero flaws in. But, after reading about the low distortion of these Hypex amps, I wanted to build a pair just to see how they compared to my Plinius. I'm not an amplifier builder, I build speakers. I know enough about how amps function to be dangerous, I've rebuilt some A/B amps but I don't own a scope, I did it with some guidance using my decent DVM. I got this Hypex mainly because they're easy, basically plug and play with some soldering, plus having used the plate amps I wanted to know how these performed on a passive speaker.
This next statement will probably trigger some debate, and before I say it, I give my word I'm not a troll, I think this is a good discussion that needs to be had... If you assume the stated power of almost all of these various class D amplifiers are measured in the same way as most class A or A/B amps, you will be seriously disappointed. Knowing that I've never personally measured the output of this specific NCx500, just based on listening to it compared to the Plinius, and based on the fairly obsessive research I've done, I think it would be more realistic to say the Hypex NCx500 is more like 150w @8 ohms, albeit a very clean, low distortion 150w.
Why does any of this matter? If you wanted to design a PA system for a large venue, and you used these (exaggerated) power ratings, you will be very disappointed. Right now, using the speakers I currently have in my system this isn't necessarily an issue- it's a 4 ohm, 9.5" Satori woofer in a 3 way so not necessarily power hungry, it plays very loud with the Hypex amps without much issue. But if I use something like a WMTMW that had a pair of power hungry woofers and I assumed I had 700w, blowing the tweeters when this amplifier clips would be a legitimate concern because there is nowhere in the vicinity of 700w of legitimate power. I think you would need something like the NC2k, which is also grossly exaggerated at 1,600w @8 ohms, it's probably more realistically 410w @4 ohms RMS (RMS power ratings are another debate altogether, but it's what most people understand).
Here's a quote from that 12 page discussion on the ASR forum, I think he nailed it but I'm curious what you guys think.
These are fantastic questions. I do know the Hypex ratings are peak power ratings, and I think those peak power ratings are based on using a 40 amp, 220v outlet lol. There is no RMS power rating anywhere for any of the class D amps that I'm aware of... Rogue and ATI come close and even state the ratings as RMS, but I'm not sure how accurate those really are.
The gain for the Hypex (using the stock buffer with the Hypex op-amps) is about 27 dB, and the Plinius gain is 38 dB. Short of swapping input buffers and using different op-amps, there technically isn't anyway to adjust gain on the Hypex amps that I'm aware of.
As far as what I used to come to my (VERY subjective) conclusions... It was a vast array of different music, everything from Katy Melua to Twisted Sister to David Brubeck, and everything in between.
The speakers are 4 ohm, a 3 way using the 9.5" Satori woofer, a 4 ohm 6.5" Satori midrange, and the Satori AMT.
The Plinius could definitely be underrated, but I doubt it's that much underrated.
Edit: what I mean by "quit giving more": I absolutely want to clarify that when this Hypex "quits giving more", it is very loud, beyond the levels of sane listening loud. That said, I was with my brother in law when we were doing this, and you can carry a (very loud) conversation with the Hypex amps cranked to their limit. I know every preamp is different, but on my preamp this is 40, once I get to 40 on the volume level they pretty much quit getting louder, which tells me that is the red zone for clipping. The crazy part is, the music is still incredibly clean up to this point, and I've not clipped the amps to my knowledge.
Whereas the Plinius is definitely louder at 40, and if I didn't care about frying my speakers it would continue to give more SPL way beyond 40. At 40, using the Plinius you aren't having a conversation because you won't be able to hear each other at all. Hopefully this all makes sense.
Last edited:
Originally I wanted to use the NC1200 for that specific reason, but opted for the lower distortion NCx500. I could still get the NC1200 amps and swap them, because they work with the same SMPS I'm using now. Would definitely be an interesting comparison, I'll research that.
Where are you test measurements? All I read here is subjective impressions. You don't sound like a manufacturer.