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PMA-NC252MP power amplifier
- Thread starter pma
- Start date
Burning Sounds
Addicted to Fun and Learning
Really nice work!
Could you measure the temp of the caps that sit above the output coils? They are right above the output coils in your module orientation so collect all the rising heat from the coils. They are 105 deg C caps so not really a concern, but I do find that is the hottest place in my amp (Apollon multi-channel NC502MP amp with the modules oriented this way.) The heatsink temps rarely get above 40deg C. Apollon add an additional heatsink to the Hypex heatsink.
Could you measure the temp of the caps that sit above the output coils? They are right above the output coils in your module orientation so collect all the rising heat from the coils. They are 105 deg C caps so not really a concern, but I do find that is the hottest place in my amp (Apollon multi-channel NC502MP amp with the modules oriented this way.) The heatsink temps rarely get above 40deg C. Apollon add an additional heatsink to the Hypex heatsink.
- Thread Starter
- #24
Thank you. Yes I could, later. By now I have “measured” temperature of those capacitors by my fingers, it is slightly above human body temperature. The hotest parts are those coils you mentioned. The side heatsink with fins does a great thermal management job, they remain slightly above room temperature. The heat should not be a killer of this amplifier, definitely.
Larry B. Larabee
Senior Member
- Joined
- Nov 24, 2021
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- 196
Bridged Mode and clipping indicators wouldn't hurt. Is the soft-start prefab?
restorer-john
Grand Contributor
@pma Keep an eye on the flexed PCB issue I have highlighted previously. I note yours is bent somewhat too.
www.audiosciencereview.com
Class D amp long term reliability
Inexpensive today? A little over ten years ago Yamaha produced their NS-1000 speakers for $1000 a pair, and sold many. Today their replacement for the NS-1000 is their NS-5000 for $15,000 a pair, which granted their replacement is quite higher performance, but it sure doesn't seem to me like...
www.audiosciencereview.com
KSTR
Major Contributor
PCB flex is guaranteed to break MLCC's in the long term -- even when those are soft-terminal type. With any ripple current present they fail in a spectacular way, simply exploding.@pma Keep an eye on the flexed PCB issue I have highlighted previously. I note yours is bent somewhat too.
Class D amp long term reliability
Inexpensive today? A little over ten years ago Yamaha produced their NS-1000 speakers for $1000 a pair, and sold many. Today their replacement for the NS-1000 is their NS-5000 for $15,000 a pair, which granted their replacement is quite higher performance, but it sure doesn't seem to me like...
- Thread Starter
- #28
@pma Keep an eye on the flexed PCB issue I have highlighted previously. I note yours is bent somewhat too.
Class D amp long term reliability
Inexpensive today? A little over ten years ago Yamaha produced their NS-1000 speakers for $1000 a pair, and sold many. Today their replacement for the NS-1000 is their NS-5000 for $15,000 a pair, which granted their replacement is quite higher performance, but it sure doesn't seem to me like...
Yeah, I am aware of your experience. One of the reasons this amp is just an evaluation sample and will be tested at least 6 months or 1 year.
Good luck with this endeavour, even if you won’t do this commercially ( I don’t know if you’re retired and end enjoy’s life ).
I don’t think it’s ott to actually heatsink these models to their maximum thermal spec , modelling the use case and life expectancy in an economic model is something for big audio companies
.
And my experience with industrial VSD’s ( variable speed drives frequency converters DC drives etc ) tells the same story about cheating on caps copper and aluminium and ventilation. Temperature management and long term reliability goes together, keep it cool ( room temperature) every degree counts.
That said the amplifier case you use may fit 2 or 3 modules ? The other side heatsink is empty for example. Could more modules fit this case and still maintain good thermal management ?
I don’t think it’s ott to actually heatsink these models to their maximum thermal spec , modelling the use case and life expectancy in an economic model is something for big audio companies
.And my experience with industrial VSD’s ( variable speed drives frequency converters DC drives etc ) tells the same story about cheating on caps copper and aluminium and ventilation. Temperature management and long term reliability goes together, keep it cool ( room temperature) every degree counts.
That said the amplifier case you use may fit 2 or 3 modules ? The other side heatsink is empty for example. Could more modules fit this case and still maintain good thermal management ?
- Thread Starter
- #30
Hello, IMO it would be absolutely safe to run 2 modules in this same case, one per heatsink and get a 4-channel amp. I would like to repeat that this sample/prototype is rather a module evaluation to me than planning a business with power amplifiers. I believe that the experience gained and disclosed might be useful for some assemblers that plan to make implementations into bigger cases like this one.
daniboun
Major Contributor
If you are interested, check this review, it is probably the best I read about the NC252MP :
archimago.blogspot.com
You amp has a neat design, but the case is very huge ) You could get a smaller one ?
I did my NC502MP in this small box, all the Alu Heatsink from the bottom of the module is also in contact with the case via a thermal paste to ensure the best thermal dissipation.
MEASUREMENTS: Hypex nCore NC252MP Amplifier (+ Subjective opinions around objective testing, and CES2020)
A blog for audiophiles about more objective topics. Measurements of audio gear. Reasonable, realistic, no snakeoil assessment of sound, and equipment.
archimago.blogspot.com
You amp has a neat design, but the case is very huge ) You could get a smaller one ?
I did my NC502MP in this small box, all the Alu Heatsink from the bottom of the module is also in contact with the case via a thermal paste to ensure the best thermal dissipation.
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- Thread Starter
- #37
If you are interested, check this review, it is probably the best I read about the NC252MP :
MEASUREMENTS: Hypex nCore NC252MP Amplifier (+ Subjective opinions around objective testing, and CES2020)
A blog for audiophiles about more objective topics. Measurements of audio gear. Reasonable, realistic, no snakeoil assessment of sound, and equipment.
You amp has a neat design, but the case is very huge ) You could get a smaller one ?
I did my NC502MP in this small box, all the Alu Heatsink from the bottom of the module is also in contact with the case via a thermal paste to ensure the best thermal dissipation.
Thank you, I think if you read this thread you would understandd why the case is "big" with big heatsinks. I want to run it at lowest temperature under any possible conditions like long-term full power. I do not want the module to be limited at 1/5 maximum power in a longer run. The module itself has idle power consumption of 15.5W (you may check in the datasheet, 8.5W SMPS, and 3.5W per amp channel). If I use the heatsink with thermal resistance of 0.4°C/W, the temperature increase at idle is +6.2°C. If you use a conventional implementation with the module mounted on sheet metal, the thermal resistance can be estimated from (and is likely several °C/W).
Flat Plate Heat Sink Calculator
The free flat plate heat sink calculator is a tool for calculating the perfomance a heat sink formed from a flat sheet of metal cool via natural convection and radiation
and the temperature will be increased much much more. The second reason is that the the 19" wide case fits to my audio components. A small box does not. I have no need to use small boxes and to reduce life span and product reliability. However I know - who cares
.So this is my design philosophy, I do not care about miniaturization at expense of reliability.
There is a good link by Hypex
BTW I know the review that you have linked here above.
Regarding your amplifier, the analog input wires are placed just above the SMPS and this is really not a good idea. I suppose it has never been measured, right? And the input XLR's placed right next to the AC mains input ....
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daniboun
Major Contributor
I shorten the cable to the XLR inputs ) BTW, these cables are shielded.
I did not measure it but compared it to the Audiophonics model, and this one is absolutely dead silence, even with your ears glued to the speakers.
I did not want to hurt you, your amp is fantastic too ) Thanks for your explanation !
here my NC252MP version
- Thread Starter
- #39
Below is the amplitude and phase frequency response, the later especially for @maty (i know he loves to see a phase response ) and maybe also for @pkane . It is measured by a 2-channel method, both amplitude and phase error of the soundcard are compensated by comparing a measured channel with a reference channel. This is more difficult to make properly in REW, which asks for impulse response delay compensation and time shift, otherwise REW gives improper results in phase response. I did not want to debate this in the PA5 thread. Please note that the NC252MP has no amplitude drop and phase deviation at 20Hz, as it is DC coupled. Again, this can be measured and verified only by the 2-channel method, otherwise the soundcard LF roll-off would be seen in the measurement.
) and maybe also for @pkane . It is measured by a 2-channel method, both amplitude and phase error of the soundcard are compensated by comparing a measured channel with a reference channel. This is more difficult to make properly in REW, which asks for impulse response delay compensation and time shift, otherwise REW gives improper results in phase response. I did not want to debate this in the PA5 thread. Please note that the NC252MP has no amplitude drop and phase deviation at 20Hz, as it is DC coupled. Again, this can be measured and verified only by the 2-channel method, otherwise the soundcard LF roll-off would be seen in the measurement.Similar threads
