BUCKEYEAMPS Hypex NCx500 Amplifier 2channel Review

[TK750]

It assumes a continuous to peak power ratio of 1/8, Imho a conservative enough figure for any musical program.
Of course not apt for torture tests as submitted by the OP.

Yes I did notice the 1/8th bit, so 150 watts continuous is the rough guide then? That seems more like an assumption rather than a limit to me?

My interpretation was that with sufficient cooling it can maintain max output not "steady" output. But that requires the system integrator to do additional work to maintain the temperature. The board itself is guaranteed for 10s without any additional thermal work by the integrator.

Ah I see, so it's guaranteed to do 1200 for 10s regardless, then if you can maintain the temp of 95 (or presumably lower) it will top out at 325 peak? I'm struggling to get what the 325W represents?
Thanks both, still not too sure about this as it's not quite how I read it but then again I am far from an experienced eye!

 

[Toni Mas]

Yes I did notice the 1/8th bit, so 150 watts continuous is the rough guide then? That seems more like an assumption rather than a limit to me?

What matters for me is that the peak value is as "real" as the continuous, and the amp gives you the necessary headroom for these transient peaks your musical program is made of. Even more real than the continuous which is merely an estimated average. Peak value are allowed by the voltaje on supply rails, nothing theoretical, nor inventable.

 

[TK750]

Right. And I think what this review/measurement is showing us is that we don’t really know what “sufficient cooling” is and the protection doesn’t kick in reliably in the way we think (from a failed Power supply; in contrast to Marantz’s implementation which has some vendor specific protection circuits).

View attachment 304073

If you look at this, it’s tricky because you have soldering irons which are 15 watts and of course, the easy bake oven, originally used a lightbulb of 100W.

Heat Sink Size Calculator | Celsia

Free online calculator used to estimate heat sink size during the initial design phase. Designed for mechanical and thermal engineers.

celsiainc.com

This lets you see how hard or easy it is to deal with heat when you don’t have a fan.

Thanks, yes I think that makes sense to me. It also seems to go along with the spec for the NCx500 datasheet which doesn't give a continuous output power but merely mentions 'Limited by thermal system implementation.' I read this as the integrator/OEM will need to do their own tests to determine a safe/appropriate number, it's interesting going through the thread and seeing how, understandably imo, people have slightly different interpretations. It does seem quite strange to me that they don't give some kind of guideline or range of expectation though. Again apologies for any misunderstanding, I'm just a layman taking things at face value!

 

[TK750]

What matters for me is that the peak value is as "real" as the continuous, and the amp gives you the necessary headroom for these transient peaks your musical program is made of. Even more real than the continuous which is merely an estimated average. Peak value are allowed by the voltaje on supply rails, nothing theoretical, nor inventable.

Makes sense to me, I agree.

 

[AltoVariago]

I am following with interest the discussion and I think that there is a very important information missing: what was the result of the ps fault?
Was there a risk of fire of other hazards?

 

[GXAlan]

It does seem quite strange to me that they don't give some kind of guideline or range of expectation though. Again apologies for any misunderstanding, I'm just a layman taking things at face value!

I’m just a hobbyist myself. I am in the category of “I don’t listen that loud, so I could be happy with a 300B SET — but if I am going to drop a lot of money on a long-term amp, it should have more power than I need”.

When I bought the Marantz PM-10, I did it for a number of reasons — and the independently measured performance clearly put it into the 600W category for 8 ohms even though it only advertised 200W into 8. But as I did more research, I can to see that HypeX talks about 100W continuous for the Nc500 which I bet will be very similar to the NCx500. The single modules in the Model 30 claims 100W into 8 while the bridged models in the PM-10 claims 200W into 8.

So, it sort of tells you that the true sustained performance of the NC500 is what HypeX posts.

For the NCx500 the spec is blank. Does it run hotter? Maybe you only get 90W because the feedback loop is larger to get the better SINAD. Is it 110W? Maybe the newer designs are better.

We don’t actually know, and it seems like it would be good to know.

 

[Buckeye Amps]

I am following with interest the discussion and I think that there is a very important information missing: what was the result of the ps fault?
Was there a risk of fire of other hazards?

No.

While trivial to some over the years (maybe, sorry if I am assuming), that is another reason why I always chose to use a fuse at the IEC input, so if something did happen catastrophic that would cause a short internally, the fuse would be another line of protection.
I say trivial as some pointed out early on when I started that the SMPS section has its own onboard fuse for such last line of protection but it is not replaceable in field so if a surge came into the amp and blew it, user would have to send back for replacement.
When it comes to electrical work, I have always tried to overdue it to make sure the worst case scenario of a fire or damage outside the amp is mitigated as much as possible. And to date, this goal has been achieved.

 

[xaxxon]

Yes I did notice the 1/8th bit, so 150 watts continuous is the rough guide then? That seems more like an assumption rather than a limit to me?



Ah I see, so it's guaranteed to do 1200 for 10s regardless, then if you can maintain the temp of 95 (or presumably lower) it will top out at 325 peak? I'm struggling to get what the 325W represents?
Thanks both, still not too sure about this as it's not quite how I read it but then again I am far from an experienced eye!

again, this is a guess, but that 325w will maintain a 95C temperature in room temperature with no active airflow.

 

[Positivevibrations]

Strange that the only products that thin blue has promoted over many years across many forums are from March Audio. Both his speakers and amps. Huge promoter of this brand.

 

[SDC]

Strange that the only products that thin blue has promoted over many years across many forums are from March Audio. Both his speakers and amps. Huge promoter of this brand.

Well I can stand for him that he is not March's avatar. Met him in person and I tell you he isn't white enough haha.

 

[Positivevibrations]

Well I can stand for him that he is not March's avatar. Met him in person and I tell you he isn't white enough haha.

Just great friends/colleagues I suppose. I just thought he ran March’s marketing department.

 

[Positivevibrations]

Looks like a 1500w supply from MicroAudio would be the ultimate solution for a stereo NCx500 amp. Probably cheaper than dual Hypex SMPS1200A700’s. Also with PFC and a few other improvements.

 

[AudioJester]

@thin bLue - another thanks for your review. Dont be diheartened by the attacks on your intentions/performance etc. - even by very senior members of this forum. When Amir publishes a less than favourable review all the owners/friends/commercial interests fall out of the woodwork and start attacking him as well.

Most of us know @Buckeye Amps is one of the good guys, honest and backs up their produts. Rather than sly remarks about you and your testing procedure, buckeye has shown his class and they have identified the problem as a faulty psu, -lets see how the replacement performs.

 

[Deleted member 48726]

One question remains for me: It possible that an home user produce the same disaster as happened on the test bench with a musical program?

Anything is possible. Think of the lines of a loud party. People connecting multiple speakers to the outputs. Using it for subwoofer duty.

 

[JSmith]

When I ran test and fried the amp, I didn't know the amp uses a Hypex SMPS1200A700 power supply.

I must say I'm surprised you didn't avail yourself of this prior to testing/pushing the amp in this way... a lesson learnt I suppose.

Great to see your thorough testing otherwise and positive to see @Buckeye Amps offering to assist as well.


JSmith

 

[peng]

My interpretation was that with sufficient cooling it can maintain max output not "steady" output. But that requires the system integrator to do additional work to maintain the temperature. The board itself is guaranteed for 10s without any additional thermal work by the integrator.

I am not sure if that means with sufficient cooling it could maintain 700 W output on continuous basis (if that's what you are alluding to?), the specs simply omit the "continuous" power output rating, leaving it to the amp builder who has to figure it out. One of them, such as Apollon, buckeye, Audiophonics could contact Hypex for clarification, if they choose to, and I hope they would.

 

[Buckeye Amps]

I am not sure if that means with sufficient cooling it could maintain 700 W output on continuous basis (if that's what you are alluding to?), the specs simply omit the "continuous" power output rating, leaving it to the amp builder who has to figure it out. One of them, such as Apollon, buckeye, Audiophonics could contact Hypex for clarification, if they choose to, and I hope they would.

The specs for the SMPS1200 do state continuous power output without any cooling (including being mounted to an aluminum chassis)

 

[peng]

Not that easy. Read heading 8.

https://www.hypex.nl/media/8c/22/86/1646037796/SMPS1200Axx0_10xx.pdf

No it isn't that easy but he could probably rate it for 325 W (or less) 4ohms, both channels driven continuously, 600 W peak (for 10s, or less) at ambient temperature <=25 deg C, and we probably won't complain. "less", if buckeye wants to be on the conservative side.

 

[xaxxon]

I am not sure if that means with sufficient cooling it could maintain 700 W output on continuous basis (if that's what you are alluding to?), the specs simply omit the "continuous" power output rating, leaving it to the amp builder who has to figure it out. One of them, such as Apollon, buckeye, Audiophonics could contact Hypex for clarification, if they choose to, and I hope they would.

again, still guessing, but a 10s max power to me says "this is not a capacitor limitation" - it's a temperature issue. I don't know of any other sources of limitations for this kind of thing. But I'm no expert.

 

[peng]

again, still guessing, but a 10s max power to me says "this is not a capacitor limitation" - it's a temperature issue. I don't know of any other sources of limitations for this kind of thing. But I'm no expert.

I agree, that's why I wish one of the authorized dealer would email Hypex for further clarification. Until then, I would not assume, or even guess that the 10s is not a limit. I am not a believer in this whole "continuous" being literally continuous. Not sure about SMPS and class D amps, but on the class AB amp side, most amps that claim continuous rating are likely not meant to be "indefinite" or unlimited time, evidence by their power supply transformer VA ratings and the look, size of the heatsinks used, and they rarely provide the details of the output devices either. For the larger power amps such as 300 W/600 W 8/4 ohms and above, truly continuous (literally) power output rating is just a tall order.