Class D amp long term reliability

[JeremyFife]

I have very mixed feelings about my Nord VL NC252MP, which I have had for more than a year. Sure it is very dynamic and has plenty of power and 'control', but I am not impressed by its (lack of) soundstaging. Channel seperation seems fine, as in left and right, but to me the thing just sounds so 2 dimentional. It's a damn shame because pairing it with my Topping DX5II makes a killer combo otherwise. But comparing it to my other amps, an audiolab 7000a and my current setup off 2x Exposure Electronics (semi-vintage) power amps with the DX5II as a preamp highlights the lack of 'depth' in comparison. Anyone else have this experience with their NC252?

It can be a tricky thing to get your head around and to accept (it was for me) but soundstage is not affected by your electronics: it's an artefact included in the recording and influenced by your speakers and room.

Essentially, it's an illusion that our brain recreates so its no wonder that it is affected by cognitive bias. Did you change your listening position or your speakers when you changed amp? Otherwise, it's probably your head messing with you as so often happens!

Plenty of thought here, and in other threads: https://www.audiosciencereview.com/forum/index.php?threads/soundstage-and-imaging.46259/

 

[pma]

It might be more complicated. The best way is to make level matched A/B (or ABX if there is a helping person) with 2 amps and a speaker switch. However, it is not trivial to make it properly, for an inexperienced user.

 

[Boredcarrot]

It can be a tricky thing to get your head around and to accept (it was for me) but soundstage is not affected by your electronics: it's an artefact included in the recording and influenced by your speakers and room.

Essentially, it's an illusion that our brain recreates so its no wonder that it is affected by cognitive bias. Did you change your listening position or your speakers when you changed amp? Otherwise, it's probably your head messing with you as so often happens!

Plenty of thought here, and in other threads: https://www.audiosciencereview.com/forum/index.php?threads/soundstage-and-imaging.46259/

I'm talking same speaker placement in the same room. The speakers aren't the issue (PMC prodigy). There is a definite difference in sound characteristics between all my components, because why wouldn't there be? Just relaying my experience - the Nord isn't bad, just way more "forward" sounding. With the other components, there is a much better sense of the placement of instruments in 3D space, something just not as aparent with the Nord. That's after many hours of comparitive listening. Again, though, that's my experience.

 

[PristineSound]

I'm talking same speaker placement in the same room. The speakers aren't the issue (PMC prodigy). There is a definite difference in sound characteristics between all my components, because why wouldn't there be? Just relaying my experience - the Nord isn't bad, just way more "forward" sounding. With the other components, there is a much better sense of the placement of instruments in 3D space, something just not as aparent with the Nord. That's after many hours of comparitive listening. Again, though, that's my experience.

I'm afraid your brain has been tricked. Look around ASR some more and you will find enough explanation as to why what you are describing is not physically possible.

 

[JeremyFife]

I'm talking same speaker placement in the same room. The speakers aren't the issue (PMC prodigy). There is a definite difference in sound characteristics between all my components, because why wouldn't there be? Just relaying my experience - the Nord isn't bad, just way more "forward" sounding. With the other components, there is a much better sense of the placement of instruments in 3D space, something just not as aparent with the Nord. That's after many hours of comparitive listening. Again, though, that's my experience.

@pma reminds me that I sometimes speak without thinking! While cognitive bias is the most likely explanation by far ... it's not the only one. I'm not in your room and I'm not hearing what you are hearing.

Unfortunately though, I also agree with PMA that the way to find out is to rule out bias issues by carrying out a blind listening comparison (level matched with good controls). I appreciate that's not a trivial exercise (I'm certainly too lazy to try).

Don't spend money to fix this issue without giving that an attempt

 

[Karmacoma]

It might be more complicated.

Could you please point to source of information explaining these complications? I'd love to learn about it. Thx

 

[pma]

Just do it. That’s my suggestion .

 

[Karmacoma]

Just do it. That’s my suggestion .

C'mon. I don't have the gear to do it and I'd like to understand what you mean. Any thread I could check on the subject?

 

[wadude]

"Hypex NC252MP Stereo Amplifier​

Apollon Audio Stereo Amplifier with stereo design with Hypex NCore NC525MP (sic) delivering power for the most demanding studio, PA or audiophile speakers with amazing clarity and brutal honest linear sound."

 

[Multicore]

There is a definite difference in sound characteristics between all my components, because why wouldn't there be?

There would be if that is the purpose it is marketed for, e.g. tone controls, room compensation, etc. Apart from that, most hifi gear is designed for and achieves transparency, i.e. not changing the sound.

 

[kyuu]

There is a definite difference in sound characteristics between all my components, because why wouldn't there be?

Why would there be a difference? Why should there be?

 

[wwenze]

This reminds me of a particular speaker that is sold in both normal wood and enameled finish which is more expensive. The manufacturer claims they sound the same. How dare they. Don't they know anything about material resonance?

 

[pma]

The signal linked below is recorded from the NC252MP output when it is loaded with (4.7ohm + 3mH)//2.2uF complex load. It is recorded directly from amp output, with no input signal. So, it is an output "noise". It is recorded in the 192kHz/24bit format and your system must be able to play such format.

https://pmacura.cz/NC252MP_4R7+3mH_2.2uF_noise_re49VrmsFS_24.wav

The signal is NOT amplified, quite opposite is true. 0dBFS digital file corresponds to 49Vrms amplifier output. NC252MP max. output is about 32Vrms, so the signal is in fact 32/49 ratio attenuated. Try it and tell me what you hear.

 

[KL....]

The signal is NOT amplified, quite opposite is true. 0dBFS digital file corresponds to 49Vrms amplifier output. NC252MP max. output is about 32Vrms, so the signal is in fact 32/49 ratio attenuated. Try it and tell me what you hear.

Thank you, yes, it will be Cliped, won't it?

 

[Petrushka]

As long as reliability is being discussed, I’d like to know why inexpensive class D amps are automatically assumed to be less reliable than expensive AB amps.

I can think of only two controllable factors that would affect reliability. One is quality of parts like capacitors that can age. The other is operating components too close to their power rating. I have seen cheap power supplies fail due to surges or brownouts.

 

[rdenney]

As long as reliability is being discussed, I’d like to know why inexpensive class D amps are automatically assumed to be less reliable than expensive AB amps.

I can think of only two controllable factors that would affect reliability. One is quality of parts like capacitors that can age. The other is operating components too close to their power rating. I have seen cheap power supplies fail due to surges or brownouts.

In some cases the issue has been thermal management of the module, at least in the case where power supplies and audio modules have shared the same board.

But my Class D amps work fine while my history has presented several examples of failed AB amps. I suspect it’s much more about design execution than concept.

Rick “anything can fail” Denney

 

[Petrushka]

In some cases the issue has been thermal management of the module, at least in the case where power supplies and audio modules have shared the same board.

But my Class D amps work fine while my history has presented several examples of failed AB amps. I suspect it’s much more about design execution than concept.

Rick “anything can fail” Denney

I have a WIIM Amp, a Sonos amp, and an $80 Aiyima amp. The Aiyima replaced a Fosi amp that failed during a power outage.
None of them get more than lukewarm in normal usage. I do not expect them to last 50 years, or to be repairable. Ten years would be nice.

 

[Jerome13]

Count me as one of the unlucky ones for my Buckeye Amp 4-channel NC252MP. Purchased March 2021, plugged into SurgeX SX-AX20E. It’s used for ATMOS with ATI AT4000 as main amplifier. Recently it randomly powers off after being on for 15-30 minutes. I’m surprised as I don’t use often, 3-4 hours per month.

 

[Buckeye Amps]

Count me as one of the unlucky ones for my Buckeye Amp 4-channel NC252MP. Purchased March 2021, plugged into SurgeX SX-AX20E. It’s used for ATMOS with ATI AT4000 as main amplifier. Recently it randomly powers off after being on for 15-30 minutes. I’m surprised as I don’t use often, 3-4 hours per month.

Apologies for the issue. I sent a response email and can definitely get you fixed up even outside warranty

 

[Bruce Morgen]

I’m surprised as I don’t use often, 3-4 hours per month.

[audiophool mode on]

Ah -- that's obviously because the amp never got a proper break-in!

[audiophool mode off]

Glad the manufacturer has stepped up -- kudos to Buckeye!