Audiophonics HPA-S400ET Review (Stereo Amplifier)

[Salt]

The provided data by Amir all show transparency independent from gain stage, so there would be only a difference if a Preamp is driven into clipping, but not by the Poweramp by itself.

 

[magchiel]

Running the LPA-S400ET in bypass with an ADI 2/4 Pro set to auto ref level, and it sounds absolutely glorious. No "lack of verve, languid or weak", whether the source is redbook, hires or vinyl. Just what's there in the mix (or not) is there.

 

[wyup]

When you say 'what's there on the mix', does it mean clinical, analytical sound or 'realistic'?
I have an impression that while these class D amps have improved, they are still about analytical, dry sound. I bought a Hypex and returned it because of that. My AB amp just sounds more realistic to the sound of instruments that I hear. The Hypex, less distortion and whatever you want, sounded coarse, dry. A violin sounded more like a electric violin. That is not what's in the mix for me.

Getting back to buffer or not, I feel that the RMI straight to the Purifi without a preamp or a buffer that 'infuses' some warmth might be too 'clean'. Maybe I'm wrong. I dont mean to stir a debate, I know this is not the place, but I'd like to know your opinion as you listen to vynil.

 

[JohnnyNG]

I have an impression that while these class D amps have improved, they are still about analytical, dry sound.

I find my 400ET to be the opposite of that and as good as the source. My LPs sound rich, detailed, and dynamic.

 

[Salt]

Then take a permanent one, be sure You like the colour (I for myself use only black for simple dimming).

 

[magchiel]

When you say 'what's there on the mix', does it mean clinical, analytical sound or 'realistic'?

Bearing in mind that I do some amateur music composition and production with more analogue guitar effects and valve amps than is good for me (more to be away from screens and complicated menus than anything else), I'd say neutral

The set is EQ'd to the room response (Harmann target) with mild acoustic treatment, so no overbearing room modes in the lows or too spikey reflections in the highs. Nothing is added to or subtracted from any source IMO. Supertramp's School on my TD160mk2 sounds clearer than ever, yet engages me from head (bobbing) to toe (tapping) - which is my benchmark. With an entirely different experience of course than a James Blake production.

Terms such as 'clinical', 'analytical' or 'realistic' really don't mean much to me (or likely something else than to you at least). The signal chain introduces no second- or third-order harmonics to goose up the music. No frequencies are boosted that trigger a psychoacoustic sense of detail or spaciousness. If you want those things, add a saturator, increase the airband and potentially a high passed room reverb every so slightly mixed in with a very short predelay to taste - your own personal mastering chain, or something to that extend. There are plenty of (free) plugins that may let you do that in the digital domain without having to hunt and spend for some esotheric hardware combination, made easier if the chain itself is completely neutral.

I myself, don't feel the slightest inclination to do so beyond said room EQ, trusting the mixing and mastering engineers have made their creative decisions on how they want to programme material to sound (and to which I may personally disagree on occasion, but to address that I should obtain the multi tracks rather than crudely fix it in my home stereo chain).

 

[bricesan]

in bypass mode it seems that there is less harmonic distortion in the speaker. the sound is super clean and dynamic. very balanced. and non fatiguing wich is an important fact for me. i use it for mixing.
with input buffer details are more forward , in bypass mode there is more dynamic depth in my system.

 

[Salt]

Providing sufficient input voltage would need no buffer. If it's really audible? Who knows.

 

[bricesan]

If you can hear harmonic distortion with a Purifi amp when using a buffer but it goes away when the buffer is disconnected then either it's in your mind or the buffer is horribly designed. I'm unable to tell a major difference except the setup without a buffer requires much more gain from the RME ADI-2 DAC FS to volume match and the volume control incremental increases are smaller with each remote volume click.

i use the audiophonics 400ET with stock opamp in the input buffer.
i don't know if it's harmonic distortion but it is how i can describe the difference i hear.

 

[totti1965]

I just realized that there is a new generation out now „Eigentakt 2“ which is the 4 th generation of Bruno Putzeys Hypex-NCore / Purify / Eigentakt Designs (since 2002 or so). Amplifiers are now mathematically fully understood and we can asume amps as a „solved problem“:

@boXem wrote:
„There are still 3 modules for Purifi: 1ET6525SA, 1ET7040SA and 1ET9040BA. The change is happening right now and a lot of manufacturers still have stock of 1ET400A waiting to be sold.“

So the next generation is the 1ET6525SA (and 1ET9040BA?). Bruno stated at one point (https://linearaudio.net/sites/linearaudio.net/files/volume1bp.pdf and also here: https://hometheaterhifi.com/30th-an...utm_id=18776575&utm_term=HTHIFI&utm_content=5) that any generation increased its qualities in round about a factor of ten since 2002 (compared to the generation before).

Buckeye and BoXem have started to sell amplifiers using these new modules in November 2024.

As an Example:

boXem - Arthur 4216/E2

2 channels HiFi power amplifier, Purifi second gen. Eigentakt technology. Designed and proudly built in Luxembourg.

boxem-audio.eu

 

[fadetoblackbs]

At some point I would ask myself if the continuous increases or improvements over time are really hearable for me or only measurable with proper equipment & written on paper.
Anyway happy to see that they keep on working and improving!

 

[anphex]

At some point I would ask myself if the continuous increases or improvements over time are really hearable for me or only measurable with proper equipment & written on paper.
Anyway happy to see that they keep on working and improving!

Nah, tbh, it's done. The only thing left to optimize is price and production optimization. We are already WAY past the point where it's audible.

 

[totti1965]

At some point I would ask myself if the continuous increases or improvements over time are really hearable for me or only measurable with proper equipment & written on paper.
Anyway happy to see that they keep on working and improving!

Of course it is not hearable! The Improvement of the 1ET6525 over the S400ET is exactly 3.5 dB if you are working with medium gain (which is about 20 dB gain): 110 dB instead of 106.5 dB SINAD.
Everything over 80 dB (0.01% Noise and Distortion) is nice and perfectly fine.
We are now reaching the limits of our measurement equipment and even Bruno can with his fourth generation digital amps not build a „tenbagger“ here. It is just twice at good measurements as the previous generation.

To improve the quality of Speakers or Analog Record Players is 30- to 100-times more important.

But perhaps it is nice to own something, which is so perfectly made!

 

[Angsty]

I just realized that there is a new generation out now „Eigentakt 2“ which is the 4 th generation of Bruno Putzeys Hypex / NCore / Eigentakt Designs (since 2002 or so). Amplifiers are now mathematically fully understood and we can asume amps as a „solved problem“:

@boXem wrote:
„There are still 3 modules for Purifi: 1ET6525SA, 1ET7040SA and 1ET9040BA. The change is happening right now and a lot of manufacturers still have stock of 1ET400A waiting to be sold.“

So the next generation is the 1ET6525SA (and 1ET9040BA?). Bruno stated at one point (https://linearaudio.net/sites/linearaudio.net/files/volume1bp.pdf and also here: https://hometheaterhifi.com/30th-an...utm_id=18776575&utm_term=HTHIFI&utm_content=5) that any generation increased its qualities in round about a factor of ten since 2002 (compared to the generation before).

Buckeye and BoXem have started to sell amplifiers using these new modules in November 2024.

As an Example:

boXem - Arthur 4216/E2

2 channels HiFi power amplifier, Purifi second gen. Eigentakt technology. Designed and proudly built in Luxembourg.

boxem-audio.eu

Can’t wait for @amirm to measure one!

 

[totti1965]

Can’t wait for @amirm to measure one!

LOL!

 

[mike70]

Of course it is not hearable! The Improvement of the 1ET6525 over the S400ET is exactly 3.5 dB if you are working with medium gain (which is about 20 dB gain): 110 dB instead of 106.5 dB SINAD.
Everything over 80 dB (0.01% Noise and Distortion) is nice and perfectly fine.
We are now reaching the limits of our measurement equipment and even Bruno can with his fourth generation digital amps not build a „tenbagger“ here. It is just twice at good measurements as the previous generation.

To improve the quality of Speakers or Analog Record Players is 30- to 100-times more important.

But perhaps it is nice to own something, which is so perfectly made!

Agree 120% ... the improvement is merely academic, and it's valid, of course.
Our ears, speakers and rooms are the devil ... we don't listen with oscilloscopes or perfect transducers / acoustics.

 

[totti1965]

Agree 120% ... the improvement is merely academic, and it's valid, of course.
Our ears, speakers and rooms are the devil ... we don't listen with oscilloscopes or perfect transducers / acoustics.

As someone who bought his first magazine on the subject of music reproduction at the age of 13 (Hifi STEREOPHONIE - January 1979) and has now been dealing with this subject for almost exactly 45 years and has repeatedly given detailed advice to friends, I tried to “condense” my findings last year:

So I developed a sheet where I wrote down my opinion on the subject of “What is how influential in the field of hi-fi”.

I divide it up as follows (and I know I'm being provocative):

Provided you have optimally produced music that has not already been destroyed by loudness wars during mastering, the following applies


45% The room and its reverberation times and their distribution.

Ideally evenly under 0.15 s in the entire frequency range. Only in the bass up to a maximum of 0.4 s


35% Positioning of the loudspeaker in the room

Preferably far away from all walls. I once heard an LS 3/5a in a room 11.5 m (37 3/4 foot) long. Torsten Roscher, the guy who demonstrated it, was able to show a whole new dimension of freedom.
Ideally, the speaker level should be 38.2% of the room length away from the rear wall. Also far away from side walls!
The listener should also sit far away from all walls to avoid early reflections (ideally 23.6% (61.8% of 38.2%) from the wall behind the listener's head - not 33.33% or 25%).


18% quality of the loudspeaker - divided into 3 x 6%:

6% frequency response linearity with emphasis on linearity of the range from 100 Hz to 2 kHz on-axis and also measured 10 degrees or 20 degrees off-axis... this is where the frequency response must fall off EVENLY slightly.

6% Bass quality (linearity, depth, cleanliness and speed of the bass)

6% other characteristics of the loudspeaker:
a) Dynamics
b) freedom from distortion (especially in the mid-range)
c) “speed” of the loudspeaker (transient behavior, mechanical losses of the most important drivers (whereby the non-linear components of the mechanical losses are particularly important - uniformly somewhat higher mechanical losses are not so bad))
d) Phase linearity and group delay


2% quality of the equipment (except loudspeakers!)

these are subdivided as follows:

1.8% non-digital sources, such as tape recorders and turntables, tonearms and cartridges as well as tonearm cables, RCA cables and speaker cables

0.2 % digital sources to enhance the quality of non digital sources (AD/DA Converters, Digital parametric Room Equalizers, Convolvers etc.), RCA cables, speaker cables to connect them with the non-digital stuff.


If only digital sources are used:

0.2 % digital sources, Digital parametric Room Equalizers, Convolvers etc., RCA cables, speaker cables

(The remaining 1.8% would then have to be added to the above 45%; 35% and 18%).

I firmly believe in this classification of relevance if you want to do something about your hearing!


thw

 

[Bob101]

As someone who bought his first magazine on the subject of music reproduction at the age of 13 (Hifi STEREOPHONIE - January 1979) and has now been dealing with this subject for almost exactly 45 years and has repeatedly given detailed advice to friends, I tried to “condense” my findings last year:

So I developed a sheet where I wrote down my opinion on the subject of “What is how influential in the field of hi-fi”.

I divide it up as follows (and I know I'm being provocative):

Provided you have optimally produced music that has not already been destroyed by loudness wars during mastering, the following applies


45% The room and its reverberation times and their distribution.

Ideally evenly under 0.15 s in the entire frequency range. Only in the bass up to a maximum of 0.4 s


35% Positioning of the loudspeaker in the room

Preferably far away from all walls. I once heard an LS 3/5a in a room 11.5 m (37 3/4 foot) long. Torsten Roscher, the guy who demonstrated it, was able to show a whole new dimension of freedom.
Ideally, the speaker level should be 38.2% of the room length away from the rear wall. Also far away from side walls!
The listener should also sit far away from all walls to avoid early reflections (ideally 23.6% (61.8% of 38.2%) from the wall behind the listener's head - not 33.33% or 25%).


18% quality of the loudspeaker - divided into 3 x 6%:

6% frequency response linearity with emphasis on linearity of the range from 100 Hz to 2 kHz on-axis and also measured 10 degrees or 20 degrees off-axis... this is where the frequency response must fall off EVENLY slightly.

6% Bass quality (linearity, depth, cleanliness and speed of the bass)

6% other characteristics of the loudspeaker:
a) Dynamics
b) freedom from distortion (especially in the mid-range)
c) “speed” of the loudspeaker (transient behavior, mechanical losses of the most important drivers (whereby the non-linear components of the mechanical losses are particularly important - uniformly somewhat higher mechanical losses are not so bad))
d) Phase linearity and group delay


2% quality of the equipment (except loudspeakers!)

these are subdivided as follows:

1.8% non-digital sources, such as tape recorders and turntables, tonearms and cartridges as well as tonearm cables, RCA cables and speaker cables

0.2 % digital sources to enhance the quality of non digital sources (AD/DA Converters, Digital parametric Room Equalizers, Convolvers etc.), RCA cables, speaker cables to connect them with the non-digital stuff.


If only digital sources are used:

0.2 % digital sources, Digital parametric Room Equalizers, Convolvers etc., RCA cables, speaker cables

(The remaining 1.8% would then have to be added to the above 45%; 35% and 18%).

I firmly believe in this classification of relevance if you want to do something about your hearing!


thw

I do agree on a lot of what you are saying, but I might be opening a can of worms here: your amp comes third and is a lot more influntetial than we like to admit, and I give it 10 %. I own the Audiophonics, use it every almost every day, except when I switch to some old AB's from time to time. Because they have a 'sound'. I switch speakers too After being in the hifi-hobby (that's what i call it for myself) for over 25 years now I learned mainly one thing: perfect reproduction is something most people don't really desire, understand and some even dislike. I sort of remember the sound of my 90's boombox at full volume. The distortion was off the scales, but it was FUN and we didn't care. I've got a pretty nice setup here now, but not many people are actually that impressed when they hear familiar music trough it, especially at first. Because they are used to radio and streaming, mainly in their cars ot trough bluetooth speakers. The DSP going on between source and ears in those situations can be mild to mindboggling. Because most people just want the artificial punch of their radio station or their speakers. It is what they conceive as 'normal', and what they think music should sound like.

 

[mike70]

I do agree on a lot of what you are saying, but I might be opening a can of worms here: your amp comes third and is a lot more influntetial than we like to admit, and I give it 10 %. I own the Audiophonics, use it every almost every day, except when I switch to some old AB's from time to time. Because they have a 'sound'. I switch speakers too After being in the hifi-hobby (that's what i call it for myself) for over 25 years now I learned mainly one thing: perfect reproduction is something most people don't really desire, understand and some even dislike. I sort of remember the sound of my 90's boombox at full volume. The distortion was off the scales, but it was FUN and we didn't care. I've got a pretty nice setup here now, but not many people are actually that impressed when they hear familiar music trough it, especially at first. Because they are used to radio and streaming, mainly in their cars ot trough bluetooth speakers. The DSP going on between source and ears in those situations can be mild to mindboggling. Because most people just want the artificial punch of their radio station or their speakers is what they conceive as 'normal', and what they think musicc shuld sound like.

you're right, but generally we're talking about "hifi" ... i mean, fidelity to the source, to what the artist and audio engineers made in the recording.
So, the opinion of people that wants "fun with lots of distortion" goes on another way (i don't talk about importance or worth / worthless).

I understand perfectly what you said (i had those experiences with "people") ... is only that we're on a niche, not on a mainstream hobby.

 

[totti1965]

I do agree on a lot of what you are saying, but I might be opening a can of worms here: your amp comes third and is a lot more influntetial than we like to admit, and I give it 10 %. I own the Audiophonics, use it every almost every day, except when I switch to some old AB's from time to time. Because they have a 'sound'. I switch speakers too After being in the hifi-hobby (that's what i call it for myself) for over 25 years now I learned mainly one thing: perfect reproduction is something most people don't really desire, understand and some even dislike. I sort of remember the sound of my 90's boombox at full volume. The distortion was off the scales, but it was FUN and we didn't care. I've got a pretty nice setup here now, but not many people are actually that impressed when they hear familiar music trough it, especially at first. Because they are used to radio and streaming, mainly in their cars ot trough bluetooth speakers. The DSP going on between source and ears in those situations can be mild to mindboggling. Because most people just want the artificial punch of their radio station or their speakers. It is what they conceive as 'normal', and what they think music should sound like.

The amps- 10 % influence? Na, meh! Only 2 % at most……
Says the man who purchased the Topping B100 50 Watts Monos yesterday at Shenzhenaudio.com because he could not resist at only EUR 470,— for a pair of the best measuring amp ever……. (Black Friday/Cyber Monday)

Our hobby is not so rational all the time….