Audiophonics HPA-S400ET Review (Stereo Amplifier)

[YSC]

Oh please don't open that can of worms. Read this thread instead.

Apollon Hypex NC2K Amplifier Teardown

This is a tear down of the recently reviewed Apollon NC2K monoblock amplifier. Both the owner and the company gave kind permission to do this. As you all know, the heart of these amplifiers are power supply and amp modules provided by Hypex to its OEMs. There are some optional parts however...

www.audiosciencereview.com

Actually that's the point why I want to ask the question. Yes it maybe not really affecting the longevity. but for a semi premium product I would always prefer the vendor who put heart into component selectiton. it's like finding OEM tyres from a supercar using second tier brand tyres...

 

[AudioSceptic]

But we unsurprisingly get what is expected performance from a close-to-reference design : 1ET400A + SMPS1200 + transparent buffer board (which is good). Minor differences are due to either production variation or Gain settings. Personally, I would spend a bit more for BoXem Arthur 4215 (for form factor, auto off/on and overall build quality) but none would "sound" any better than the other.

For those who don't know, there's also a cheaper version, with the exact same components in a smaller case:View attachment 194315View attachment 194320

AUDIOPHONICS LPA-S400ET Class D Stereo Amplifier Purifi 2x400W 4 Ohm - Audiophonics

We are proud to offer you the Audiophonics LPA-S400ET, a Class D stereo power amplifier based on two Purifi 1ET400A modules. This ready-built and ready-to-use version is for audiophiles who want to equip themselves with a foolproof amplification

www.audiophonics.fr

Am I right in thinking that Audiophonics uses just 2 enclosures for all their Hypex and Purifi amps: a wide one like the one Amir tested, which can have up to 4 channels, and this narrow one that can be mono or stereo? <https://www.audiophonics.fr/en/amplifier-audiophonics-workshop-c-6421.html> Makes a lot of sense, doesn't it? Gives better economy of scale when buying them in, and any extra space inside just improves cooling and separation.

I think I'd go for a 2x mono setup with short speaker cables and longer interconnects. I'm almost sorry that I don't need an amp right now.

 

[Kegemusha]

I almost went for Audiophonics Hypex 122 unit but decided on Topping PA5. This shows that I would have been happy with either choice

I got the Hypex 122 from them, I am very happy with the Audiophonics one, nothing to complain. Good price per watt.

 

[nagster]

Very cool! So the secret sauce is in the buffer. Cant quite see what the opamp is?

Would be nice if the gain switches were on the outside so could change without needing to open up.

Why is it so hard to add a gain selector knobs on the back, it's just some simple wires changing the way the jumper pins are short circuited.

As for the mechanism that affects the performance depending on the mounting method such as the gain switching mechanism, the method using the jumper pin on the buffer board is rational. (Especially for low-priced products)
Performance and reliability degradation is minimal. The cost is also minimal.
However, those who switch daily will need to be able to operate with the front panel or the rear panel.

 

[nagster]

Just for sound. I do owned another french product that product that has XLR and RCA offered. The designer say on website not to use XLR. RCA sound better on his product. Some power amp you can compensate the gain loss. Of course, you have email them.

Products that produce an audible difference between the XLR and RCA inputs under the right circumstances have failed in design.
It is correct if they designed it for coloring purposes.

 

[kapardian]

Questions: Is current an important measure on how an amplifier controls the base and lower frequencies. Is the current and peak currents measured in these testings? What are typical current numbers for class D amps vs class A or AB?

 

[PeteL]

Questions: Is current an important measure on how an amplifier controls the base and lower frequencies. Is the current and peak currents measured in these testings? What are typical current numbers for class D amps vs class A or AB?

Output Power is a current measurment, you can deduct it with ohms law, the 4 and 8 ohms measurments are resistive loads.

 

[nagster]

No harm keep asking. I don't know anything about Hypex and Purifi differential amplifier design. So I speculate on product description. If they don't wanna use differential amplifier design as their marketing hype. I alway assume RCA is better.

3 meter is just a guide. Some 200kg Class A heater you need to put on floor. You need to have longer interconnect to connect from racks. This is you may need to use XLR. Many heaters I know recommend XLR. All based on designer recommendation. Some audiophile used to put pre and source by their sofa side, XLR are highly need. Those different ways to place components you can see all in hifi show. Of course, you can see how people do it in Youtube too.

Twisted pair (quad) cables connected to balanced inputs are resistant to external noise.
Ground loops and common mode noise are not directly linked to the signal cable length.

 

[vert]

Having dealt with them a few times over the past years, they are an incredible company to deal with. They were every time super competent and courteous. I'm very happy for them that they get such well-deserved recognition. They have been an inspired company for many years. Hailing from France I remember happier times when companies able and/or willing to pursue excellence were more common than they seem to be today. So I'm very pleased to see what Audiophonics is able to achieve.

 

[RichT]

Fantastic work Amir, we finally have a great one! There sure is a nice pile of parts outside of your testing room though. Thanks so much for doing all of this work, regards

 

[dtaylo1066]

Audiophonics makes some terrific stuff -- typically well designed from aethetics to performance. What's not to like in this amp.

 

[pma]

Purifi is most likely using around 22 kHz bandwidth,

I really do not think so. If you start analysis with @22kHz BW setting, then the analysis finishes at 10-11 kHz. It would not allow you to go to 20kHz and they show 20kHz top frequency. You need at least @40kHz BW to make such measurement.

As a comparison, THD frequency plots of my re-design of vintage Kenwood amp

from

Measurements of vintage Kenwood KA-5010 amplifier clone - Now with SMPS!

I made some improvements in power supply section and in wiring. As a result, the amplifier is completely free from mains spuriae lines and other mess. High order harmonics have been also considerably reduced. More THD vs. frequency plots at 2W - 40W/4ohm and @45kHz BW

www.audiosciencereview.com

I would have hoped that Purifi would have better HF linearity than this thing, but it does not seem to be the case.

 

[Spocko]

Reminds me my early days in audio, when I was choosing gears by the amount of components and weight...

And then we discovered the lead bars stuck inside once cases were opened!

 

[Spocko]

$1,700 - damn good deal. Shows that you don't need to spend $tupid money to buy a SOTA amp with lots of power. What are the companies providing that are charging $25k and up for a power amp? Lots of them out there.

They give you a pair of white gloves and a case that is 2 inch thick aluminum billet laser cut with their logo on it.

 

[Rick Sykora]

This piece isn’t perfectly parallel to the case so this amp gets a headless panther vote from me.

/sarcasm

View attachment 194304

Lol, while get the sarcasm, may really not be all that great. If is relying on the trigger mounts to hold the board, that is not a solid mechanical approach...

While clearly not affecting performance, there are several questionable wiring runs. The AC wire and the power switch wire should run along the board edge rather than through the middle of the SMPS.

Additionally, some of the signal input wiring seems longer than it needs to be.

In the end, seems a nice value. Just could be a bit tidier IMO.

 

[mdsimon2]

@amirm can you post a FFT of 5 W in to 4 ohm at 15 kHz showing 45 kHz bandwidth?

Curious what the spectra looks like associated with the high frequency non-linearity shown in the power sweeps.

Michael

 

[mdsimon2]

I really do not think so. If you start analysis with @22kHz BW setting, then the analysis finishes at 10-11 kHz. It would not allow you to go to 20kHz and they show 20kHz top frequency. You need at least @40kHz BW to make such measurement.

As a comparison, THD frequency plots of my re-design of vintage Kenwood amp

from

Measurements of vintage Kenwood KA-5010 amplifier clone - Now with SMPS!

I made some improvements in power supply section and in wiring. As a result, the amplifier is completely free from mains spuriae lines and other mess. High order harmonics have been also considerably reduced. More THD vs. frequency plots at 2W - 40W/4ohm and @45kHz BW

www.audiosciencereview.com

I would have hoped that Purifi would have better HF linearity than this thing, but it does not seem to be the case.

Here's the excerpt from the datasheet which shows they are using 20 kHz AES17 LPF.

I guess the Purifi plot makes sense in that you see a slight decrease in THD+N at higher frequencies as the harmonics are being filtered out but in general all the traces are pretty flat because THD+N is dominated by noise? Curious if anyone else has a better explanation.

Michael

 

[batfunk]

I have Audiophonics hpa 400nc(hypex nc 400 version) for two years( i missed purifi version release for one month...).
The only problem i got was at the reception, one channel was still active after turning off amp. Mailed them, sent it back same day, they repaired it and sent it back to me the SAME day they received it...
Excellent after sale, glad for them with those excellent measurements and implementation

 

[pma]

Here's the excerpt from the datasheet which shows they are using 20 kHz AES17 LPF.

View attachment 194429
I guess the Purifi plot makes sense in that you see a slight decrease in THD+N at higher frequencies as the harmonics are being filtered out but in general all the traces are pretty flat because THD+N is dominated by noise? Curious if anyone else has a better explanation.

Michael

You can make a bit faked THD+N measurement with @22kHz bandwidth, the highest distortion component is at 11kHz H2 and the rest to 22kHz is only noise. 20Hz-11kHz THD+N, 11kHz-22kHz only N. It is a trick and fake and the manufacturer have possibly done it this way. Amir does it right with @45kHz BW.

 

[don'ttrustauthority]

I have been thinking of buying against all reason the new Schiit amp with it's big choke, but it's a monoblock at the same price as this, and I live in Florida.

Perhaps I'll give the Schiit a pass and keep my low powered solution intact.