BUCKEYEAMPS Hypex NCx500 Amplifier 2channel Review

[Buckeye Amps]

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.

Yes, temp dependent (specs say “until Tsink reaches 95C).

Hypex tests/rates the SMPS in a free air situation so the max rating is how long 1200w can be sustained until the temp hits target (95C).
Continuous rating is how much wattage it will put out when the temp stabilizes at 95C, again in a free air situation.

People brought up the CPU as an analogy earlier. Same principle as for CPUs. Once a thermal limit is hit, throttling occurs.

 

[Buckeye Amps]

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.

Again, no need for clarification. All the information is in the spec sheets.
(Not trying to sound snarky. Just stating).

 

[peng]

Yes, temp dependent (specs say “until Tsink reaches 95C).

Hypex tests/rates the SMPS in a free air situation so the max rating is how long 1200w can be sustained until the temp hits target (95C).
Continuous rating is how much wattage it will put out when the temp stabilizes at 95C, again in a free air situation.

People brought up the CPU as an analogy earlier. Same principle as for CPUs. Once a thermal limit is hit, throttling occurs.

Again, I agree such interpretation seems reasonable, but it is still an assumption, or our educated guess. I would not take that to the bank until Hypex confirm that as long as the heatsink temperature can be kept to 95 deg C or below, the PS can sustain 1200 W continuously, indefinitely, with no time limit, ie non stop, forever lol..

 

[Buckeye Amps]

Again, I agree such interpretation seems reasonable, but it is still an assumption, or our educated guess. I would not take that to the bank until Hypex confirm that as long as the heatsink temperature can be kept to 95 deg C or below, the PS can sustain 1200 W continuously, indefinitely, with no time limit, ie non stop, forever lol..

I can certainly inquire but this is where the line from practical to impractical comes into question because in what use case would anyone need 1200w for a speaker (or pair of speakers) for longer than 10s?

 

[restorer-john]

Again, I agree such interpretation seems reasonable, but it is still an assumption, or our educated guess. I would not take that to the bank until Hypex confirm that as long as the heatsink temperature can be kept to 95 deg C or below, the PS can sustain 1200 W continuously, indefinitely, with no time limit, ie non stop, forever lol..

The spec sheets don't say that at all.

10 seconds at 1200W and the heat spreader hits 95 degrees C in free air.

325W will be able to be sustained with the heat spreader stabilising at 95 degrees C.

It would need a large finned attached heatsink and forced air cooling as it is needing to disipate around 140W of heat at 1200W- just from the SMPS. The amp modules will produce twice that. No simple folded aluminium case is going get rid of that much heat on a continuous basis.

 

[peng]

Again, no need for clarification. All the information is in the spec sheets.
(Not trying to sound snarky. Just stating).

You are making an assumption, absolutely not trying to sound snarky as either. That part of the data sheet has been posted multiple times now, it never stated clearly that the time duration can continue on for longer than 10 s, as long as temperature stabilized at or below 95C.

Here it is one more time just so it is clear, as the thread is getting too long to turn the pages back:

So, to quote @xaxxon , "again, this is a guess, but that 325w will maintain a 95C temperature in room temperature with no active airflow." That sounds like a reasonable guess too. I wish your interpretation is the right one, but to be on the safe side, for now I would rather assume it is 325 W, not 1200 W if one wants to define continuous to mean literally continuous, with not time limit.

 

[restorer-john]

I can certainly inquire but this is where the line from practical to impractical comes into question because in what use case would anyone need 1200w for a speaker (or pair of speakers) for longer than 10s?

The line is clear. Are you promoting and selling amplifiers that can achieve their advertised, rated specifications or not? It pretty simple. People are basing their buying decisions on your power output numbers.

 

[peng]

The spec sheets don't say that at all.

10 seconds at 1200W and the heat spreader hits 95 degrees C in free air.

325W will be able to be sustained with the heat spreader stabilising at 95 degrees C.

It would need a large finned attached heatsink and forced air cooling as it is needing to disipate around 140W of heat at 1200W- just from the SMPS. The amp modules will produce twice that. No aluminium case is going get rid of that much heat on a continuous basis.

I am with you on this, that's why I suggested until and unless we are told otherwise by Hypex, that amp should be rated 325 W (or less if one wants to be on the conservative side) for continuous output to mean output continuously non stop with no time limit.

 

[Buckeye Amps]

The line is clear. Are you promoting and selling amplifiers that can achieve their advertised, rated specifications or not? It pretty simple. People are basing their buying decisions on your power output numbers.

View attachment 304181

I plan on adding Peak Output qualifier to the ratings once I do a website update later this week.

 

[Buckeye Amps]

I am with you on this, that's why I suggested until and unless we are told otherwise by Hypex, that amp should be rated 325 W (or less if one wants to be on the conservative side) for continuous output to mean output continuously non stop with no time limit.

Correct

 

[peng]

I can certainly inquire but this is where the line from practical to impractical comes into question because in what use case would anyone need 1200w for a speaker (or pair of speakers) for longer than 10s?

I understand your point totally. To me, the whole lengthy discussion so far has been much more about the accuracy of specification interpretation, and much less about practicality/real world use.

 

[restorer-john]

I plan on adding Peak Output qualifier to the ratings once I do a website update later this week.

Hypex's terms are good. They state the amplifiers can be driven to continuous clipping on music signals with the 1200W supply. That's what people listen to.

Not sine waves.

 

[Buckeye Amps]

I understand your point totally. To me, the whole lengthy discussion so far has been much more about the accuracy of specification interpretation, and much less about practicality/real world use.

For accuracy I would say peak 1200w, continuous 325w.

The brief posts of mine regarding 1200w being possible for longer with proper active cooling were a discussion exercise and not meant to try to change the continuous rating.

 

[Buckeye Amps]

Hypex's terms are good. They state the amplifiers can be driven to continuous clipping on music signals with the 1200W supply. That's what people listen to.

Not sine waves.

I totally agree. But a lot of people want to know the max as well.
So the least I should be doing is adding the peak power words to the advertised ratings.
I actually thought I had it in the ratings at one point during a revision of my website but obviously not.

 

[peng]

I plan on adding Peak Output qualifier to the ratings once I do a website update later this week.

That would be great! I would further suggest you just reference Hypex data sheet and let them take responsibility of the specifications and the way they have written them. That's because I don't feel their specs are totally clear either, though still better than many other amp manufacturers datasheets. And if they are good enough to provide any further clarifications, then you can include such info on another update.

 

[Buckeye Amps]

That would be great! I would further suggest you just reference Hypex data sheet and let them take responsibility of the specifications and the way they have written them. That's because I don't feel their specs are totally clear either, though still better than many other amp manufacturers datasheets. And if they are good enough to provide any further clarifications, then you can include such info on another update.

I’ve actually been meaning to see if I’m allowed to do a consolidated data sheet for Hypex and Purifi (include all the relevant/easy to understand finer details and specs) as the average consumer can easily (based on feedback directly from said consumers) get lost or overwhelmed merely linking to the entire data sheets.

I always need to remind every now and then that these discussions we have on ASR are only representative of a small percentage of AV hobbyists.

 

[peng]

I’ve actually been meaning to see if I’m allowed to do a consolidated data sheet for Hypex and Purifi (include all the relevant/easy to understand finer details and specs) as the average consumer can easily (based on feedback directly from said consumers) get lost or overwhelmed merely linking to the entire data sheets.

I always need to remind every now and then that these discussions we have on ASR are only representative of a small percentage of AV hobbyists.

Sorry I didn't mean to suggest you include their whole data sheets but just the power output of the amp modules and power supplies based on the wording and terminologies provided/use on the datasheet. I should have said anything as I trust you are going to do it anyway.

 

[thin bLue]

Very detailed photos were sent of both the NCx modules and the SMPS and the owner + reviewer both noted swelling of one or more capacitors and the smell of burnt plastic. This, along with the behavior of the SMPS continuously clicking (endless cycle), it was easy to determine the SMPS failed. If it was the NCx modules, the MCU of our buffer board would have reported a fault via Red LED on the front.

Regarding sending out replacement parts vs. whole replacement amps: I leave this to the discretion of each customer. Whenever an issue is reported, I always offer a return/replacement procedure OR ask the customer if they are comfortable enough replacing a the defective part on their own. One of the benefits of a more modular build system.

I heard from the owner that you have decided to recall the parts. It's a costly and difficult decision, but that'll be able to provide a more detailed analysis. Claps x 999!

 

[Positivevibrations]

Good rule of thumb. When building module based class D amps with external power supplies, always use power supplies with a continuous power rating of at least 20% more than what the amp modules can draw when hitting their internal current limiters. Simple solution to avoid issues.

 

[Positivevibrations]

Hypex's terms are good. They state the amplifiers can be driven to continuous clipping on music signals with the 1200W supply. That's what people listen to.

Not sine waves.

If the current limiters in the amps don’t trigger before the power supply, the supply is undersized for the application. Dual NCx500’s, being driven with an equal signal, will trigger their internal current limiters at 27A each. So a 54A load on the supply. This exceeds the capability of the SMPS1200A700. Therefor it was an improper choice for the application (using 1 of them for 2 modules anyways) Regardless if there was no better option readily available.