Class D amp long term reliability

[Mort]

I think the very obvious point is that the anecdotal evidence alone does not present a strong enough case at this stage, but backed up by Tibor's report, based on what must be a very reasonable amount of data and the technical analysis he has provided to explain that data, we can definitely see a pattern.

 

[Buckeye Amps]

You probably have missed it, in additional to the anecdotes, there is actual data point provided by one manufacturer, then it caused a firestorm from that point on.

Also, you keep bringing this point up, that people have been piling on Apollon. Unless I missed some sort of egregious post by another member(s), I remember that after Apollon posted their failure rate the discussion turned to inquiring about what the rate was before and after the latest NC252MP module revision (mid 2020). I don't think anyone was attempting to argue that Apollon was lying/misleading/responsible for their observed rates.

Am I missing something?

 

[Apollon Audio]

I would like to clarify the technical basis for my view that the Hypex MP series involves more design compromises and, as a consequence, exhibits a higher failure rate compared to Hypex’s higher-end standalone modules and Purifi solutions.

The primary reason is component selection, which differs significantly between product lines. To focus on a single, objective example: electrolytic capacitors.
The NC252MP / NCx252MP modules employ Aishi electrolytic capacitors, which are typically rated for 2,000 hours at 105 °C. By comparison, the Rubicon capacitors used in Hypex NCx500 modules and Purifi-based designs are commonly rated for 10,000 hours at 105 °C. This is not a marginal difference, it represents a fivefold increase in rated operational lifetime under identical thermal conditions.

While it is true that higher-grade components would increase the cost of MP series modules, the impact of these choices on long-term reliability and service life cannot be ignored. These specifications are factual and directly relevant when discussing product longevity.

In addition, the all-in-one architecture of the MP series introduces inherent thermal disadvantages. In these modules, the Class-D amplifier stage and the SMPS power supply are integrated onto a single PCB. This results in:

- Higher average operating temperatures for temperature-sensitive components
- Greater thermal stress on electrolytic capacitors and power semiconductors
- Reduced thermal separation between heat-generating subsystems

By contrast, Purifi-based designs and higher-end Hypex solutions typically employ separate amplifier and power-supply boards, allowing for improved airflow, lower localized temperatures, and more controlled thermal management. This architectural separation directly contributes to increased reliability and longer component life.

In summary, the MP series represents a cost-optimized, space-efficient solution, but this is achieved through tangible trade-offs in component quality and thermal conditions. These trade-offs explain why the MP series tends to show higher failure rates compared to Hypex’s higher-end modules and Purifi implementations. This is not a criticism of the concept itself, but a realistic assessment of the engineering compromises inherent in all-in-one module designs.

I understand why many manufacturers strongly defend these modules. From an implementation standpoint, they are extremely convenient. An all-in-one MP-series module requires little more than a mains connection, an audio input, and a speaker output to become a finished product. The input buffer, power supply, and Class-D amplifier stage are all integrated, which significantly reduces development time, wiring complexity, and assembly effort.

By contrast, solutions based on high-end modules such as the NCx500,NC2K, NC1200 or Purifi require a more involved design process. External power supplies must be selected and integrated, additional buffer stages are needed, grounding and layout become more critical, and component placement must be optimized to achieve the best possible performance. These designs are inherently more complex, take longer to develop and assemble, and are consequently more expensive to manufacture.

From a purely commercial and production perspective, all-in-one solutions are therefore very attractive. They allow manufacturers to bring products to market faster, with lower development effort and reduced production costs, which naturally improves margins and short-term profitability.

That said, while we at Apollon Audio also use these modules and offer amplifiers based on them, I believe it is important to be transparent about their limitations. Acknowledging the technical drawbacks of all-in-one designs does not diminish their usefulness; it simply reflects an honest, engineering-based assessment. These are factual trade-offs inherent to the architecture, not subjective opinions, and they should be openly recognized when discussing performance, longevity, and design philosophy.

 

[rf1938]

Nice post.

 

[Matias]

A "mic drop" post. 'Nuff said.

 

[Taiga]

Yes, but can’t the increased complexity of separate components from the higher end systems introduce more variables that assemblers must optimize in order to produce a product with the desired performance and reliability? In other words, isn’t the quality of the final product more dependent on the skill of the assembler (as compared to the MP modules) and leave more room for the assembly to be botched or to perform less than optimally? How would the average end user know whether or not the system was assembled in the best possible manner? This of course can be said for the MP systems as well, but more skills seem to be needed for the higher end systems.

Is there more here that I am not understanding?

 

[Chr1]

Oof. At page 64, I fear this thread is about to go into another circle/repeat of the same points, ala groundhog day again.

(And again. Maybe this is just the nature of online forums tho. ho hum)

 

[Tone]

Nah, just trust the manufacturer/builder to build it properly, and be honest, and stick around to help if worse happens.

Just don't expect perfection in every way in every product regardless of cost.

End of thread..

Yeah right!

 

[Tone]

"That said, while we at Apollon Audio also use these modules and offer amplifiers based on them, I believe it is important to be transparent about their limitations. Acknowledging the technical drawbacks of all-in-one designs does not diminish their usefulness; it simply reflects an honest, engineering-based assessment."

This especially, Apollon Audio know their onions.

 

[Tone]

"How would the average end user know whether or not the system was assembled in the best possible manner?"

Reputation.

 

[Sokel]

I would like to clarify the technical basis for my view that the Hypex MP series involves more design compromises and, as a consequence, exhibits a higher failure rate compared to Hypex’s higher-end standalone modules and Purifi solutions.

The primary reason is component selection, which differs significantly between product lines. To focus on a single, objective example: electrolytic capacitors.
The NC252MP / NCx252MP modules employ Aishi electrolytic capacitors, which are typically rated for 2,000 hours at 105 °C. By comparison, the Rubicon capacitors used in Hypex NCx500 modules and Purifi-based designs are commonly rated for 10,000 hours at 105 °C. This is not a marginal difference, it represents a fivefold increase in rated operational lifetime under identical thermal conditions.

While it is true that higher-grade components would increase the cost of MP series modules, the impact of these choices on long-term reliability and service life cannot be ignored. These specifications are factual and directly relevant when discussing product longevity.

In addition, the all-in-one architecture of the MP series introduces inherent thermal disadvantages. In these modules, the Class-D amplifier stage and the SMPS power supply are integrated onto a single PCB. This results in:

- Higher average operating temperatures for temperature-sensitive components
- Greater thermal stress on electrolytic capacitors and power semiconductors
- Reduced thermal separation between heat-generating subsystems

By contrast, Purifi-based designs and higher-end Hypex solutions typically employ separate amplifier and power-supply boards, allowing for improved airflow, lower localized temperatures, and more controlled thermal management. This architectural separation directly contributes to increased reliability and longer component life.

In summary, the MP series represents a cost-optimized, space-efficient solution, but this is achieved through tangible trade-offs in component quality and thermal conditions. These trade-offs explain why the MP series tends to show higher failure rates compared to Hypex’s higher-end modules and Purifi implementations. This is not a criticism of the concept itself, but a realistic assessment of the engineering compromises inherent in all-in-one module designs.

I understand why many manufacturers strongly defend these modules. From an implementation standpoint, they are extremely convenient. An all-in-one MP-series module requires little more than a mains connection, an audio input, and a speaker output to become a finished product. The input buffer, power supply, and Class-D amplifier stage are all integrated, which significantly reduces development time, wiring complexity, and assembly effort.

By contrast, solutions based on high-end modules such as the NCx500,NC2K, NC1200 or Purifi require a more involved design process. External power supplies must be selected and integrated, additional buffer stages are needed, grounding and layout become more critical, and component placement must be optimized to achieve the best possible performance. These designs are inherently more complex, take longer to develop and assemble, and are consequently more expensive to manufacture.

From a purely commercial and production perspective, all-in-one solutions are therefore very attractive. They allow manufacturers to bring products to market faster, with lower development effort and reduced production costs, which naturally improves margins and short-term profitability.

That said, while we at Apollon Audio also use these modules and offer amplifiers based on them, I believe it is important to be transparent about their limitations. Acknowledging the technical drawbacks of all-in-one designs does not diminish their usefulness; it simply reflects an honest, engineering-based assessment. These are factual trade-offs inherent to the architecture, not subjective opinions, and they should be openly recognized when discussing performance, longevity, and design philosophy.

All-in one is always a compromise, no matter the BOM.

The moment I got my hands on the two icepower 1200a2 I use for lows as monos I knew that their days where numbered (no matter their premium components)

Loading them with nearly all their controls and monitoring abilities, plus hooking up a 300a2 on each of them at the edge of their working range does not help either.
Their idle temp (their big heatshinks I have them mounted on are at about 39° C at idle and get stranglely cooler when I play at normal levels) is also a good index of not expecting decades of service. It's not even a bet at their cost as it's is very, VERY low, so... (eight channels at the end of the day, no matter if I use them as mono so only four)

So, I treated them as such all this time (I'm just passing the five-year mark) and wait, I have subjected them to any hard (but sane) condition possible, I have repeatedly challenged their protections (can't get them to clip though, I clip first) and they are nice as toys in general, lots to play with.

When they die I will probably mount some Purifis at their heatshinks (hopefully Purifi will have their own PSU by then)* and I will treat them the same way.
That's the value of such modules, and that's the proper (by my opinion) way to think about them, as gear ready to swap at any given time at minimal cost.

*Edit: unless icepower's Conductor tech has passed to the higher power modules, then no Purifi, will still stick to ice.

 

[Tone]

A bonus of higher cost is better reliability given adverse conditions, or at least it should be.

Does anyone disagree?

 

[Tone]

A bonus of higher cost is better reliability given adverse conditions, or at least it should be.

Does anyone disagree?

And from a company that supply 'V-L' products all the way up to 1ET9040..

Still here, must be some reason.

Coat, gone (mic drop).

Tongue-in-cheek, like.

 

[Taiga]

"How would the average end user know whether or not the system was assembled in the best possible manner?"

Reputation.

A bonus of higher cost is better reliability given adverse conditions, or at least it should be.

Does anyone disagree?

I believe there are a sufficient number of reviews on this site revealing that “reputation” and “higher cost” do not necessarily correlate with better reliability, performance, or build quality.

I do not “disagree” that it “should be” the case.

Some sellers even like to advertise that their more expensive equipment sounds better than their less expensive equipment despite objective measurements showing that any differences are outside of the range of human hearing.

 

[Buckeye Amps]

Some sellers even like to advertise that their more expensive equipment sounds better than their less expensive equipment despite objective measurements showing that any differences are outside of the range of human hearing.

+1

 

[Tone]

"Some sellers even like to advertise that their more expensive equipment sounds better than their less expensive equipment"

That could be seen as subjective.

Spending more should give you a better product.

Note that it is not just me that would say a 9040 will drive those speakers to limits and not bat an eyelid whilst sounding superb, all day and night.

And an NCx252MP will sound a million dollars with a nice pair of medium sized domestic speakers, and be reliable.

 

[Buckeye Amps]

That could be seen as subjective.

Spending more should give you a better product.

Saying a Purifi 1ET9040BA sounds better than, say, an NC502MP is subjective and falls apart in the face of measurements when both are used within their designed limits.
But of course when one amp is pushed past its limits compared to one that isn't there can be audible differences (distortion, clipping), no one ever argues against that.

 

[Tone]

Buckeye and Nord Acoustics shake hands, and support Apollon, so it would seem.

 

[0bs3rv3r]

In other words, isn’t the quality of the final product more dependent on the skill of the assembler

Actually no. Assembly is so easy and trivial to implement well these days, but nothing can be done about an electrolytic cap that will fail sooner, under same conditions.

 

[Tone]

9040 is rated 1200W into 2ohms, vanishing distortion and extremely low output impedance.

May not be relevant to some but it costs to deliver those figures reliably.