BUCKEYEAMPS Hypex NCx500 Amplifier 2channel Review

[GXAlan]

Would hope good test practices are being applied but would be good to see them demonstrated too. Whether Amir, or I or any other tester, the test rig needs to be in a known trusted state prior (and after testing) or the results will be suspect. Do not care how good or expensive the test rig is, if the tester does not demonstrate discipline around solid test practices, speculating on the results (and drawing conclusions based on them) is counterproductive. More testing is needed. Until that happens, suggest that owners should continue to enjoy their amp.

In the heyday of home THX certification, I remember that there were a lot of reliability features like being able to short the amplifier outputs without destroying it. THX Ultra amplifiers are required to swing an 18A peak.

“They have logged the dynamic content of virtually every piece of finished sound track they can get their hands on (we’re talking hundreds of sound tracks here) and from that developed a practical “dynamic” requirement for multi-channel power amplification.”

THX-Certification - HomeTheaterHifi.com

THX is almost a quarter century old, and its Consumer Branch has been around since 1990, yet people still do not have a proper understanding of THX. Maybe that's THX's fault, maybe it's ours (the press) . . .

hometheaterhifi.com

Maybe we need ASR certification like THX certification? Can offset the testing time with fees that they feed toward licensing?

Maybe all that talk about THX certification no longer being relevant is false?

Metrics Tested on THX Amplifiers:
Reference Output Voltage
Voltage Gain
Output Current
Output Source Impedance
Overload Restoring Time
Stability with Capacitive Load
Harmonic Distortion and Noise
Modulation Distortion
Difference-Frequency Distortion
Noise Output Voltage
Phase Response
D.C. Offset at the Output
Hum
Crosstalk
Acoustic Noise Level
Mechanical Noise
Input Sensitivity
Input Impedance
Output Impedance
Load Impedance Range
Voltage Output Capability
Current Output Capability
Transient Output Capability
Transient Overload Recovery Time
Asymmetrical Clipping
Frequency Response
Phase Margin
Radiated Interference
Conducted Interference

 

[sarumbear]

What do you mean by no specs for the PSU at all? It is measured when powering an amplifier when relevant, and otherwise specified.

What I meant is there is no Amper rating for a power supply. Which is odd to the extreme and certainly does not make the spec of a PSU complete.

If the two units are meant to work together then give the specs for the combined unit. Otherwise intentional or not the specs are confusing at best.

Anyhow, we shouldn’t care about the Hypex specs. They are parts of an amplifier. We need to know the specs of the amplifier. And, those are totally missing!

 

[PeteL]

What I meant is there is no Amper rating for a power supply. Which is odd to the extreme and certainly does not make the spec of a PSU complete.

If the two units are meant to work together then give the specs for the combined unit. Otherwise intentional or not the specs are confusing at best.

Anyhow, we shouldn’t care about the Hypex specs. They are parts of an amplifier. We need to know the specs of the amplifier. And, those are totally missing!

 

[peng]

*This amplifier fails to repeatedly achieve top power of the right end of this graph.
Drive this amplifier to near 700 W as officially rated can cause serious irreversible damage.

Important!
For 20 kHz <- Filter had set as 20 -20 kHz so, higher frequency's harmonic distortions are heavily filtered so, THD+N look way finer than real value. So It should be ignored or carefully considered.


Continued on the next post due to image limit up to 35.

Thank you for the great work. I just have one point to make as follow:

It seems to me buckeye amp, the manufacturer who assemble the unit, may be just quoted Hypex, the actual manufacturer of the power supply and amp modules. Hypex's specs are not as detailed as I would like and in this case, they simply indicated:

Peak Output Power 1kHz, THD=1% 700 W 4 ohms They apparently never mentioned the test duration.

So my question is, what was your test duration when you measure the power output into 4 ohms? For argument sake, it might be able to survive 1 kHz, THD 1%, 4 ohms, for 200 ms, or even 5s?

As for buckeyeamp, I think they should clearly state in their specs that the 700 W 4 ohm rating is based entirely on Hypex specs under Hypex test conditions (they should get that from Hypex). I would love to email Hypex about their test conditions for the 700 W rating, but I know they would refer me to the authorized amp "manufacturers" such as buckeye, Nord, NAD, Apollon etc.

Manufacturers, not just buckeyeamp, should also include in their specs, the power supply requirements for the NCx500 to output 700 W 4 ohms, and again, for how long. Hypex's spec in their datasheet was clear about for continuous rating, that it is "Limited by thermal system implementation", but nothing was said about the duration for the "Peak Output power".

Many manufacturers do the similar thing of not providing the duration for their output power rating. I wonder if in doing so, they felt okay to specify more impressive numbers and still legally, or just morally protected lol..

 

[sarumbear]

Maybe we need ASR certification like THX certification? Can offset the testing time with fees that they feed toward licensing?

What a brilliant idea!

@amirm’s CV should ease the way into manufacturers.

 

[Sokel]

View attachment 303965

I think that is the specs of the auxiliary output,can't imagine such low amperage from the mains.

 

[Toni Mas]

Anyhow, we shouldn’t care about the Hypex specs. They are parts of an amplifier. We need to know the specs of the amplifier. And, those are totally missing!

This is what i dont like in this kind of offer: the biggest part of the value is brought around the Hypex name. What added value do these builders ( Buckeye, Audiophonics, etc...) have (or miss) to bring us?

 

[sarumbear]

View attachment 303965

Am I blind or there is no output current value on that table?

 

[sarumbear]

This is what i dont like in this kind of offer: the biggest part of the value is brought around the Hypex name. What added value do these builders ( Buckeye, Audiophonics, etc...) have (or miss) to bring us?

They save you from DIY. They do the DIY in a larger scale.

It’s a way to start but by now they should have taken the responsibilities of a manufacturer themselves.

 

[Toni Mas]

They save you from DIY. They do the DIY in a larger scale.

It’s a way to start but by now they should have taken the responsibilities of a manufacturer themselves.

Agree

 

[Tom22]

Regarding reproducibility: I can say we have stressed tested a few different NCx builds with the SMPS1200A700 and never had an issue leading to the SMPS "frying" itself. As of right now I am considering it a one off, which can happen unfortunately. Hence getting a new SMPS sent out right away per warranty.

Regarding a "beefier" SMPS....there are things in the works to possible switch away from all Hypex SMPS models, yes. But no timeline for that at all.

Very interesting approach in this whole debate on PSUs, if I read all this from a customer‘s (not expert) perspective, there seems to be room for improvement. I wonder if the Micro Audio SMPS passes the ASR test, so it would be great to see a review of these Buckeye Monos

 

[peng]

Am I blind or there is no output current value on that table?

There are some specs on the values:
Keep in mind, since they specified 700 W, 4 ohm is the max power output under the stated conditions, they can reasonably expect the users can calculate the current value under the same conditions. Again, what's lacking is the duration. If continuous current is rated is say, 10A, instantaneous current could be rated much higher, even 100 A or higher, it depends a lot on duration. As an example, Denon's 50 WPC integrated amp, the PMX-1 limited is rated 60 A instantaneous, and their lower model is rated 120 W, but 120 A instantaneous current. They all play the number games, just in different ways! So most or all of them will likely fail thin blue's honest tests.

 

[peng]

Okay, so, I missed a few post and now we know Hypex did provide some duration specs for the power supply. If that's what failed, we still need thin blue to tell us if he subjected the dut at conditions more severe than specified by Hypex based on not only current, power output but also the duration and heatsink temperature. As mentioned by others, the power supply and amps are still considered very powerful for a lot of people, we are now mainly discussing technical specs as published vs as measured only.

 

[PeteL]

Am I blind or there is no output current value on that table?

I think as Sokel mentioned they are for the Aux outs. My bad. You may be right, for actual output current you will have to use ohms law. Now altough after a bit more reading I'll admit that it is a datasheet crafted not as a general purpose PSU and assumed that it will be used with their own modules in amp design. You are allowed to not like that but hey it's a 17 page spec sheet. Comprehensive enough for the purpose. I think when you said "No power specs at all for the SMPS" Is quite off. It tells you how much power it delivers when used in an amplifier.

 

[restorer-john]

OK. It's really simple.

Continuous power is just that. No pissing around.

How much continuous power can your amplifier deliver at its rated distortion, bandwidth and at what load impedance? Not for 10 seconds. Not for 30 seconds. Not for for 1 minute before exploding. 5 minutes is the latest 'cop-out', but for me, it should be indefinite.

 

[sarumbear]

There are some specs on the values:
Keep in mind, since they specified 700 W, 4 ohm is the max power output under the stated conditions, they can reasonably expect the users can calculate the current value under the same conditions. Again, what's lacking is the duration. If continuous current is rated is say, 10A, instantaneous current could be rated much higher, even 100 A or higher, it depends a lot on duration. As an example, Denon's 50 WPC integrated amp, the PMX-1 limited is rated 60 A instantaneous, and their lower model is rated 120 W, but 120 A instantaneous current. They all play the number games, just in different ways! So most or all of them will likely fail thin blue's honest tests.

View attachment 303972View attachment 303973

There it is. I must have missed it. It clearly says the power supply current limit is not protected and if you drain enough power you can damage the unit. As @thin bLue demonstrated.

 

[sarumbear]

I think when you said "No power specs at all for the SMPS" Is quite off. It tells you how much power it delivers when used in an amplifier.

The SMPS is not the power amplifier. it’s a free standing unit. Do you measure a power amplifier output power by the SPL value of a speaker connected to it? Then why would you measure the power supply output capacity with the power output of the amplifier its feeding?

 

[Sokel]

It clearly says the power supply current limit is not protected

I read that the max amperage is spec'd as "guarded" so that's not may be true.
Agreed about other specs.

 

[sarumbear]

I read that the max amperage is spec'd as "guarded" so that's not may be true.
Agreed about other specs.

Hence the confusion and incompleteness of the specs.

 

[restorer-john]

@Apollon Audio How about addressing your misrepresentation I spoke of in post #102? Waiting...

Hint: Admit to the deception.