Audiophonics HPA-S400ET Review (Stereo Amplifier)

[Vhond]

But Audiophonics and Apollon also use Nilai (Apollon versus Audiophonics)??

As far as I know Nilai is distributed for DIY only and (still) not OEM.

 

[Salt]

Hypex did the same when introducing N-Core: first DIY (maybe for Beta -Testing?) and then OEM.
Audiophonics is a parts distributor and thus DIY products are available for them.
In the course of time there will be more Nilai products in the market as is with N-Cores.

 

[Vhond]

Hypex did the same when introducing N-Core: first DIY (maybe for Beta -Testing?) and then OEM.
Audiophonics is a parts distributor and thus DIY products are available for them.
In the course of time there will be more Nilai products in the market as is with N-Cores.

What do you mean with 'in the course of time'? Nilai is available since the end of 2022 and I can't imagine Nord Acoustics isn't aware of that? I know a new implementation/design is not developed in a few weeks, but after more than a year?

 

[SonicSleuth]

How can they justifiably charge so much for an empty box, it's gotta be £100 at most. I personally see absolutely no value in it. Can't fix it when it inevitably dies.

 

[Bob101]

How can they justifiably charge so much for an empty box, it's gotta be £100 at most. I personally see absolutely no value in it. Can't fix it when it inevitably dies.

I use ducktape to fix empty boxes

 

[maruko]

Hi, I need some help.

I use a Topping A90 as a preamp connected via XLR to the Audiophonics HPAS400ET.

I use the “M” gain setting on the Topping (+6dB).

Since my DAC is a Topping D90 connected via XLR (4V out) to the A90, so the output voltage to the Audiophonics amp should be 8V.

The Audiophonics gain buffer is set to off, so with this setting the amp has 10V input sensivity.

Since I perceive a loss of low frequencies energy (I feel it like “weakness”) and a predominance of medium-high frequencies with this setting (compared to the configuration with input buffer ON And even more compared to other AB class amplifiers I had such as the Pass X150 and Gamut D200), I wonder if it is only my subjective impression or if indeed, it may depend on the fact that the input impedance of the amplifier with the deactivated buffer is “only” 4k Ohm, instead of the 96K Ohm with the active buffer.

Since the output impedance of the Topping A90 is only 40 Ohms, should be sufficiently low compared to the input impedance of the amplifier with the input buffer set to off (ratio of 1:100, 10 times greater the 1:10 rule of thumb).

My speakers are B&W 702S2 with 87dB sensivity and work at 6 Ohm most of the time with 3 Ohm peaks.

Solved!

I changed my old speaker cable with new Canare 4S11 and now all is ok. Low frequencies are now present and powerful. I don’t feel any lack anymore. Especially if I go up in volume, but also at lower volumes.
So I use M gain on Topping A90 and buffer bypass on the Audiophonics. It is a delightful sound.

I don’t know if the old cable can be the problem, since it was oxidated and unused for a long time. Or maybe its electrical characteristics. Or simply maybe I’m in a good mood or changed something in my room acoustic.

 

[maruko]

But I have another question.

I’m not an expert but I’m curious and since I’m studying and discovering audio science world little by little tanks to this forum, in the Audio Precision literature I read about parameters like “slew rate” or/and “rise time” and, If I got it right, It has to do with dynamics (fast attack and transients) of an amplifier. Right?

I came across it while I was searching the internet about why Spectral amplifications were wide bandwidth. And what was it for. Thus discovering that it would be the only way to reach high levels of slew rate.

So I’m wondering if this is an important measurement still today, also in class D amplifier, since can’t find it in Amir review of this amp.
Any documentation about slew rate of Purifi modules?

 

[Bob101]

But I have another question.

I’m not an expert but I’m curious and since I’m studying and discovering audio science world little by little tanks to this forum, in the Audio Precision literature I read about parameters like “slew rate” or/and “rise time” and, If I got it right, It has to do with dynamics (fast attack and transients) of an amplifier. Right?

I came across it while I was searching the internet about why Spectral amplifications were wide bandwidth. And what was it for. Thus discovering that it would be the only way to reach high levels of slew rate.

So I’m wondering if this is an important measurement still today, also in class D amplifier, since can’t find it in Amir review of this amp.
Any documentation about slew rate of Purifi modules?

'Slew rate' is a characteristic that, by their nature, does not apply to Purifi amps. I think class D amps in general. There is an interview with Bruno Putzeys, the developing engineer behind Purifi, where he specifically adresses this. It has something to do with the bandwith-limited nature of class D. I'll try to track the interview down and post a link if I can.
As I understand and remeber it (please correct when I'm wrong):
There was a period where high amplifier bandwidth (far beyond the audible frequency region) was marketed as a measure of quality. Because of the way slew rates were measured, higher bandwidth amps had a faster slew rate by default. As marketing goes, high bandwidth amplifiers weren't necessarily actually 'faster' where and when it mattered, it just meant the measurements looked more favourable.

 

[TNT]

does not apply to Purifi amps

Of course it "applies" but as the class D amps are not so wideband they will not compare favorly. So its a smart move to say that its "not applicable"... one can very well measure it for the Purifi amp.

Rise time is not interesting at all as long as the power bandwidth is say double hearing range.... 40-50kHz.,,, which it is here...

//

 

[Nxt0206]

Hello new here on the forum,

I would like to get advice on whether my intended setup will work.

I currently own a pair of Kef R500 with an Arendal 1723 1S subwoofer

I would like to control this with a wiim ultra (pre/dac/streamer) and as a poweramp this audiophonics purifi.

the space is in an 80s average Dutch living/dining room. 45m2
speakers are on the long wall, 2.5m apart and I sit about 2.5m from the TV (in the middle) I don't listen extremely loud (baby) so I like that the speakers are still at low volume sound good. My source is Tidal & spotify connect.

I am in favor of what something measures well but also sounds good. From this forum I learned that the purifi is excellent. My only question is, will it match with wiim ultra as pre? Reason for asking is that i have 0 technical knowledge about where to look to match a pre amp with poweramp. Because ive read in the hifi world people match for “synergy” .. if that is real

I have quite a tight budget and prefer to get a bang for the buck. Maybe the purify is even overkill?

I look forward to your responses!

 

[magchiel]

I am in favor of what something measures well but also sounds good. From this forum I learned that the purifi is excellent. My only question is, will it match with wiim ultra as pre? Reason for asking is that i have 0 technical knowledge about where to look to match a pre amp with poweramp. Because ive read in the hifi world people match for “synergy” .. if that is real

The only matching that I consider real is that of impedance matching and with well engineered products such as the Audiophonics HPA/LPA-S400ET and the WiiM (couldn't find any impedance measurements that quickly but they may be out there) I wouldn't consider this an issue. Assuming the Ultra will measure at least as well as the Pro Plus, both will be inaudibly neutral and with the PEQ in the WiiM you can room correct and dial in your preferences, rather than embark on esotheric matching of imperfect components that may provide an optimum synergy by cancelling eachother out. Or something to that effect.

the space is in an 80s average Dutch living/dining room. 45m2
speakers are on the long wall, 2.5m apart and I sit about 2.5m from the TV (in the middle) I don't listen extremely loud (baby) so I like that the speakers are still at low volume sound good

I'm running the LPA-S400ET at a similar distance with 90dB/W/m sensitivity (yours are 88dB/W/m) and have never increased the volume on my ADI-2 beyond -17dB (and that is on mostly older tracks that have low mastering levels - something that can also be fixed through library normalising). At lower volumes you'll find some equal loudness contours coming into play. Again you can EQ that in to taste with the WiiM if you always run at those lower levels and you're missing oomph.

I have quite a tight budget and prefer to get a bang for the buck. Maybe the purify is even overkill?

You could save quite a few bucks going for the HPC-S250NC (or the IOM Ncore that argubualy has nicer esthetics stacked with the WiiM), that will give you roughly half (~= -3dB) of the max output of the Purifi and at of course slightly worse measurements. If you would howewer notice any decrease in performance, especially at lower volumes, even in a double blind test, I seriously doubt. And since you have a sub to do the heavy lifting for the (power hungry) subbass frequencies, you'll use even less of that amp power. The question if you can lay that difference in measurements and headroom to rest in your mind. I couldn't .

 

[Nxt0206]

The only matching that I consider real is that of impedance matching and with well engineered products such as the Audiophonics HPA/LPA-S400ET and the WiiM (couldn't find any impedance measurements that quickly but they may be out there) I wouldn't consider this an issue. Assuming the Ultra will measure at least as well as the Pro Plus, both will be inaudibly neutral and with the PEQ in the WiiM you can room correct and dial in your preferences, rather than embark on esotheric matching of imperfect components that may provide an optimum synergy by cancelling eachother out. Or something to that effect.



I'm running the LPA-S400ET at a similar distance with 90dB/W/m sensitivity (yours are 88dB/W/m) and have never increased the volume on my ADI-2 beyond -17dB (and that is on mostly older tracks that have low mastering levels - something that can also be fixed through library normalising). At lower volumes you'll find some equal loudness contours coming into play. Again you can EQ that in to taste with the WiiM if you always run at those lower levels and you're missing oomph.



You could save quite a few bucks going for the HPC-S250NC (or the IOM Ncore that argubualy has nicer esthetics stacked with the WiiM), that will give you roughly half (~= -3dB) of the max output of the Purifi and at of course slightly worse measurements. If you would howewer notice any decrease in performance, especially at lower volumes, even in a double blind test, I seriously doubt. And since you have a sub to do the heavy lifting for the (power hungry) subbass frequencies, you'll use even less of that amp power. The question if you can lay that difference in measurements and headroom to rest in your mind. I couldn't .

Wow thank you for this insightful response ill have a look at the alternatives to save some buck

 

[bricesan]

I'm using this configuration (bypass, A90 medium gain) and IMHO is the best.

i am also using the audiophonics purifi in bypass buffer mode and it is the better solution to my hears.
less noise, more neutrality, a lot of dynamics !
i use a lynx aurora (n), output 10v volt and 100 ohm like a d90 and i really don't miss bass.

 

[Joel G]

i am also using the audiophonics purifi in bypass buffer mode and it is the better solution to my hears.
less noise, more neutrality, a lot of dynamics !
i use a lynx aurora (n), output 10v volt and 100 ohm like a d90 and i really don't miss bass.

Interesting. I am considering getting the Topping A70 pro since i would love to be able to hear music with headphones at times, and I like the 20k input impedance ohms it offers, for my Ares 12. I might try again the bypass mode of the power amp when I get it. After reading some of the comments i think that my feeling of “less energy” might be attributed to not being used to play the pre90 to higher volume levels, and the subjective feeling of not “getting the power” I was used to (seeing different numbers on the screen affecting subjectively my listening). But I don’t have my Pre90 anymore, only a passive pre, so I look forward to trying it again some time soon with an A70

 

[Rick Sykora]

As far as I know Nilai is distributed for DIY only and (still) not OEM.

Hypex discounts Nilai for their OEMs. However, a Nilai amplifier module costs substantially more than the NCx500 module does. Given a marginal difference in performance, a Nilai implementation is difficult to justify charging a premium for an OEM to offer. So, while Nilai is not exclusively DIY, its cost prices it out of consideration for OEMs.

 

[bricesan]

Interesting. I am considering getting the Topping A70 pro since i would love to be able to hear music with headphones at times, and I like the 20k input impedance ohms it offers, for my Ares 12. I might try again the bypass mode of the power amp when I get it. After reading some of the comments i think that my feeling of “less energy” might be attributed to not being used to play the pre90 to higher volume levels, and the subjective feeling of not “getting the power” I was used to (seeing different numbers on the screen affecting subjectively my listening). But I don’t have my Pre90 anymore, only a passive pre, so I look forward to trying it again some time soon with an A70

indeed numbers on the screen should not be considered
just use your ears
the revelant numbers you could use with your eyes are the db pressure in the room to match the level with or without the buffer.
use a db meter to match the volume, even a free app like db volume would do the job and try to hear the difference at the exact same level of listening.
at same acoustic pressure in the room (around 75-80db weighting C in slow response) the buffer bypass is clearly a way better sounding solution to me.

 

[mike70]

indeed numbers on the screen should not be considered
just use your ears
the revelant numbers you could use with your eyes are the db pressure in the room to match the level with or without the buffer.
use a db meter to match the volume, even a free app like db volume would do the job and try to hear the difference at the exact same level of listening.
at same acoustic pressure in the room (around 75-80db weighting C in slow response) the buffer bypass is clearly a way better sounding solution to me.

Well, you're using much more than only your ears ... "only your ears" usually is the mantra of the "audiophile crew".

 

[Bob101]

I don't have devices that put out 10+ Volts, so I have no opinion on the sonic experience bypassing the buffer board.

Bruno Putzeys himself said in an interview that the unbuffered input of a Purifi module can be 'not a very friendly' host to an audio source. And that even if you don't strictly need the gain, a buffer board is in his opinion advisable anyway.

 

[bricesan]

I don't have devices that put out 10+ Volts, so I have no opinion on the sonic experience bypassing the buffer board.

Bruno Putzeys himself said in an interview that the unbuffered input of a Purifi module can be 'not a very friendly' host to an audio source. And that even if you don't strictly need the gain, a buffer board is in his opinion advisable anyway.

intersting could you source this itw ?

in a discussion on Michael Andrew's youtube channel he admit he personally use it without buffer stage.

i think the question is not if your source put out 10v
but do you miss sound pressure in your room (volume) ? at full output of your source or pre.
if yes, use the buffer stage.
that'a how i think.
to my hears the buffer stage of the audiophonics (with stock opamp) reduce the dynamics, everthing is compressed in the first plan.
wich could be pleasefull and seem more detailed but i prefer full depth and nuances.

 

[JohnnyNG]

Bruno Putzeys himself said in an interview that the unbuffered input of a Purifi module can be 'not a very friendly' host to an audio source. And that even if you don't strictly need the gain, a buffer board is in his opinion advisable anyway.

Even though my Topping Pre90 can ostensibly deliver 10+ volts I do prefer my Audiophonics MPA-M400ET monos with buffer in place.