Hypex NC1200: Quality of the implementations

[maty]

Graphs of the NC500 ATM buffers with the different op-amps:

https://www.acoustic-technology.com/en/blog-atm-en/buffer-for-hypex-nc500-v3-smd-part-ii

Different measurements have been made to the PCB of the SMD buffer (V3) of the NC500 module. Different operational amplifiers have been used to check the behavior of each of them individually and see how it can affect the sound in the power module...

 

[maty]

I found this DIY implementation of the Hypex NC400. I was struck by the internal partitioning with thick aluminum walls.

https://hifiwigwam.com/forum/topic/73228-hypex-power-amp-build/

-> https://www.aluminiumwarehouse.co.uk/

 

[Matias]

Nice, I never knew there were so many nc1200 based amplifiers!

 

[amirm]

I found this DIY implementation of the Hypex NC400. I was struck by the internal partitioning with thick aluminum walls.

It is nice but i would have made the right channel mirror image. That would make manufacturing simpler by using same cable setup for both, and make the leads smaller as is the case with the left channel.

 

[Thomas savage]

@March Audio dose yours come with a extra thick tin foil hat ? If not can I have my money back ?

Adjusted for currency fluctuation of course ..

 

[March Audio]

He also attached me the PDF of the measurements he made of the different op-amps with his AudioPrecision APX525 device.

PDF, 366 KB each

* http://maty.galeon.com/WP-imagenes/hard/pdf/LM4562-v3.pdf

* http://maty.galeon.com/WP-imagenes/hard/pdf/LME49720-v3.pdf

* http://maty.galeon.com/WP-imagenes/hard/pdf/MUSES01-v3.pdf

* http://maty.galeon.com/WP-imagenes/hard/pdf/SS3602-v3.pdf

* http://maty.galeon.com/WP-imagenes/hard/pdf/994-v3.pdf

* http://maty.galeon.com/WP-imagenes/hard/pdf/Burson-v3.pdf

This is interesting data. First question is why is the LM4562 performance so far off the TI datasheet values. THD + N 106dB v 130dB? Whilst I wouldn't expect the idealised levels seen in the TI datasheet, that's a fair way off. Could be board layout.

Just noticed that it's an AP525, it's performance only acheives 110dB THD + N.

So we have several buffers here that are poor performers, Burson and Muse. The performance of the others are actually very similar which reinforces what I have said previously and what Amir has measured in his tests.

If any of the selection will sound significantly different it will be the ones that are 20dB or more deficient in THD + N.

 

[March Audio]

I found this DIY implementation of the Hypex NC400. I was struck by the internal partitioning with thick aluminum walls.

https://hifiwigwam.com/forum/topic/73228-hypex-power-amp-build/

View attachment 28784

-> https://www.aluminiumwarehouse.co.uk/

View attachment 28785

That's great. Now show some measurements of with and without that Alu. So we can see if it actually made a difference.

 

[March Audio]

Graphs of the NC500 ATM buffers with the different op-amps:

https://www.acoustic-technology.com/en/blog-atm-en/buffer-for-hypex-nc500-v3-smd-part-ii

Aahhh now the plots in this link confirmed my suspicion about the LM4562 board layout. See how much lower the distortion is on the second set of plots with the revised board.

The next issue is that this is just the boards in isolation. What are the measurements of the buffer plus amp?

 

[March Audio]

Just for reference, here is some of the Texas Instruments data on the LM4562 performance. 0.00003%, thats -130dB. However as mentioned earlier, probably challenging to achieve that in a real world implementation.

Some people seem to think this is "mediocre" or somehow inadequate......go figure.....

 

[March Audio]

@March Audio dose yours come with a extra thick tin foil hat ? If not can I have my money back ?

Adjusted for currency fluctuation of course ..

@Thomas savage Free audiophile RF cancellation device with every purchase! $5320 dollar value, all for free.

Guaranteed to make blacks blacker and lift 7.83 veils. PRAT will improve by 100%. You will be 100% PRAT.

 

[maty]

I agree with the LM4562, it is not a disaster as it says bavmike / Mivera. I had thought about commenting on it.

The original problem is that the first buffers were created with the Sonic Imagery in mind and then they were adapted for other op-amps.

Over time the buffers underwent small modifications so that more op-amps worked correctly. However, we must never forget that they were optimized for the Sonic Imagery, which is why it was my choice years ago.

What I mention, has to know it bavmike / Mivera. At first one can make mistakes -like me with Burson- but with the passage of time it was clear that the responsible was the bad implementation of the op-amp in a buffer not created specifically for it.

Those drawings of jalejos years ago I commented in the thread on the NC500 where everything originated, in diyaudio.com

https://www.diyaudio.com/forums/vendor-s-bazaar/281361-hypex-ncore-nc500-build.html

For me, measurements have always been an important factor but in audio at the end our ear/brain is the final arbiter.

 

[March Audio]

For me, measurements have always been an important factor but in audio at the end our ear/brain is the final arbiter.

Unfortunately the reality is that with accurate audio assessment in the end our ear / brain the final barrier

 

[maty]

Using those images to discredit technical knowledge that is well known for decades is not typical of an engineering lover.

The products must be designed and built according to the actual conditions of use and not those of a controlled environment such as a laboratory.

Imagine a sports car with the suspension set to work only on a racing circuit. It occurs to us to use it on the road -real world- with the degraded asphalt, with potholes ... the occupants will suffer great discomfort.

 

[March Audio]

Using those images to discredit technical knowledge that is well known for decades is not typical of an engineering lover.

The products must be designed and built according to the actual conditions of use and not those of a controlled environment such as a laboratory.

Imagine a sports car with the suspension set to work only on a racing circuit. It occurs to us to use it on the road -real world- with the degraded asphalt, with potholes ... the occupants will suffer great discomfort.

Of course products need to be designed and built for real world conditions, thats why you perform lab tests - to validate performance. EMC compliance, load testing etc. I have no idea what you are referring to with your "discredit" comment. Just for info I used to represent Keysight (formerly Agilent/Hewlett Packard) products including those used to perform RF testing and EMC compliance.

In the example above, just throwing in some aluminium doesnt mean any EMC problem (thats assuming there is one in the first place) is solved.

My point above was that whilst the ear/brain may be the final arbiter, it must be accepted that combination is often fooled, inaccurate or just plain biased.

Comparisons must be performed under controlled conditions.

 

[maty]

The picture with the helmet was redundant because it has not been used with the intention of causing a laugh but to discredit.

The reality is that Class D technology amplification uses internally a large frequency band unlike other technologies so extra precautions have to be taken.

 

[boXem]

@Thomas savage Free audiophile RF cancellation device with every purchase! $5320 dollar value, all for free.

Guaranteed to make blacks blacker and lift 7.83 veils. PRAT will improve by 100%. You will be 100% PRAT.


View attachment 28804

Is it the prototype from your MkII amplifiers case?

 

[March Audio]

The picture with the helmet was redundant because it has not been used with the intention of causing a laugh but to discredit.

The reality is that Class D technology amplification uses internally a large frequency band unlike other technologies so extra precautions have to be taken.

No it really was funny

Which with the Hypex design they have. Please look at the plots I showed of the LACK of RF coming out of the units. If you dont understand the plots please ask for clarification.

 

[maty]

I think you do not want to understand me. If in your laboratory you do not have atmospheric RF/EMI problems like I have in my house, evidently with a minimum thickness it will be enough, and even without an external box.

Imagine that I buy your amplifier with its current box. If I place it on a piece of furniture whose shelves are glued on the bottom with cheap silicone, painted and invisible, a 1mm galvanized stainless steel sheet and it sounds better ... And now I move it to another part of the house where it does not have that extra cheap protection ... whose fault will it be that it sounds worse?

Being such an expensive product it is illogical to try to save on the thickness of aluminum, in my opinion.

The logical thing would be that you add the option of a box with greater aluminum thickness paying an extra.

You are still in time, I think you would increase sales.

 

[March Audio]

I think you do not want to understand me. If in your laboratory you do not have atmospheric RF/EMI problems like I have in my house, evidently with a minimum thickness it will be enough, and even without an external box.

Imagine that I buy your amplifier with its current box. If I place it on a piece of furniture whose shelves are glued on the bottom with cheap silicone, painted and invisible, a 1mm galvanized stainless steel sheet and it sounds better ... And now I move it to another part of the house where it does not have that extra cheap protection ... whose fault will it be that it sounds worse?

Being such an expensive product it is illogical to try to save on the thickness of aluminum, in my opinion.

The logical thing would be that you add the option of a box with greater aluminum thickness paying an extra.

You are still in time, I think you would increase sales.

Maty, with respect I am quite confident you have no idea what the RF/EMI conditions are like in your house. Have you performed an RF survey with something like this? (I used to sell these BTW)

https://www.keysight.com/en/pcx-x205201/fieldfox-handheld-rf-and-microwave-analyzers?cc=AU&lc=eng

Tell us how you would measure the electrical output of the amp and asses sound quality in a controlled and blind manner to see if your sheet of steel did anything?

 

[maty]

It is not worth continuing with the theme, at least in this thread.

Do what you think is convenient with your business. My advice was in good faith.