Audiophonics HPA-S400ET Review (Stereo Amplifier)

[anphex]

I heard about coil whine on graphics cards due to high modulating frequencies, but in a capacitor...? I've read that it could be due to a tiny gas leak causing whistling, maybe vibrations.
Since ALL caps seem to be the cause this is unlikely. Maybe a very weird ground loop or a faulty grounding in your house?

 

[tmtomh]

I heard about coil whine on graphics cards due to high modulating frequencies, but in a capacitor...? I've read that it could be due to a tiny gas leak causing whistling, maybe vibrations.
Since ALL caps seem to be the cause this is unlikely. Maybe a very weird ground loop or a faulty grounding in your house?

I've not heard of capacitors making noise either, but I just checked Wikipedia for "coil whine," and there is a subsection on capacitors:

Electromagnetically induced acoustic noise - Wikipedia

en.wikipedia.org

Normally my first suspicion would be a ground loop too, as I've found they can create a lot more kinds of noise than just hum. However, ground loops don't produce mechanical hum with the power amp completely off in my experience. I've heard the effects of a ground loop with source components/preamp off, but in my experience the power amp - the device at the end of the signal chain of components - had to be on, and that was because what I was hearing came through the speakers, not directly from the components.

For component mechanical noise, there's also the issue of DC in the AC feed, which is very common. But again, I would not expect that to be the issue here because DC-induced mechanical noise usually comes from large linear PSUs rather than the small switching ones in these amps.

Very strange indeed.

 

[fourdogslong]

I'm new to the forum, glad I found this!

Does anybody know if the monoblock version of this Audiophonics purifi amp is as good as the stereo version reviewed here?

From the pictures on their website it looks more cramped inside with power cables flowing over the amp. Not sure if that can affect it or not.

 

[Daka]

I'm new to the forum, glad I found this!

Does anybody know if the monoblock version of this Audiophonics purifi amp is as good as the stereo version reviewed here?

From the pictures on their website it looks more cramped inside with power cables flowing over the amp. Not sure if that can affect it or not.

I have mono block and it’s flawless.
Actually thinking of replacing those two monos for one triple from them - to save space. If anyone from UK interested please ping me.

 

[fourdogslong]

I have mono block and it’s flawless.
Actually thinking of replacing those two monos for one triple from them - to save space. If anyone from UK interested please ping me.

That's good to know, thank you!

 

[delgesu]

Ordered a mono pair of this amp today. Not sure whether they have this gain setting too ... If so, what gain would be your recommendation for my setting for topping pre90 / DAC90SE (balanced)?
Thanks!

 

[Streamc]

Ordered a mono pair of this amp today. Not sure whether they have this gain setting too ... If so, what gain would be your recommendation for my setting for topping pre90 / DAC90SE (balanced)?
Thanks!

Minimal. I use my eval 1 with input buffer turned off, bypassed. It depends of output impedance of DAC, pre and input impedance of amp with buffer or not. Second must be bigger. With buffer turned on input impedance is bigger. Listen or not? Depends on your choice. Gain would be enough.
I used it even with buffer turned on. But I do not need such a gain.
Also I ve questioned this to Bruno Putzeys by asking him how to use it wit smsl MK2 with buffer or not. I receive answer from him.

Actually the simplest solution is to try and compare by ear. On my system, the amp sounds best without buffer because my DAC can handle low impedance loads. But I have heard DACs that did not like the low impedance and in that case it sounded better with the buffer. It’s difficult to predict without knowing the exact output circuit of the DAC. So just try and hear what sounds best to you.

 

[nemesis.ie]

@delgesu

The specs for the mono one doesn't seem to include the 3 gain settings like they do on the other Purifi-based models. It's jumpers on the buffer boards (designed by Audiphonics themselves), so it would likely be easier to have all of them come with the jumper pins in place (or all done during part prep).

The description does mention it though:

I'm hoping my 4 channel one ships out this week.

 

[hiphop_odc]

There are gain settings on the monoblocks

 

[kenshone]

Ordered a mono pair of this amp today. Not sure whether they have this gain setting too ... If so, what gain would be your recommendation for my setting for topping pre90 / DAC90SE (balanced)?
Thanks!

There are indeed gain settings on the monos. The chip layout is a bit different than the pictures they show for their stereo Purifi amp. You can find the input sensitivity at each gain level in this review or probably on the Audiophonics site.

All you would do is lookup the output voltage from the D90SE and match that to the right gain level in terms of input sensitivity. That way you're using the smallest possible gain (and hence lowest possible added distortion) while still being able to drive the amp to max power with your D90SE.

 

[Streamc]

There are indeed gain settings on the monos. The chip layout is a bit different than the pictures they show for their stereo Purifi amp. You can find the input sensitivity at each gain level in this review or probably on the Audiophonics site.

All you would do is lookup the output voltage from the D90SE and match that to the right gain level in terms of input sensitivity. That way you're using the smallest possible gain (and hence lowest possible added distortion) while still being able to drive the amp to max power with your D90SE.

also check input output impedance. The output impedance stays rock solid at 100 Ohms on both outputs. from https://soundnews.net/sources/dacs/topping-d90se-dac-review/
So it is very good. Even for using with input buffer bypassed.

 

[nemesis.ie]

Great. I will probably be using bypassed as my processor has high output voltage.

 

[fourdogslong]

Ordered a mono pair of this amp today. Not sure whether they have this gain setting too ... If so, what gain would be your recommendation for my setting for topping pre90 / DAC90SE (balanced)?
Thanks!

Let us know how they sound once you get them!
I'm considering replacing my Anaview AMS-1000 stereo amp with those, mostly because my speakers are far apart and I want to keep cables short.

 

[kenshone]

Let us know how they sound once you get them!
I'm considering replacing my Anaview AMS-1000 stereo amp with those, mostly because my speakers are far apart and I want to keep cables short.

If you're used to big, heavy amplifiers for big power, you'll be surprised at how small this amplifier is for the SPL it can produce. I have some monos and they sound as good as advertised.

 

[fourdogslong]

If you're used to big, heavy amplifiers for big power, you'll be surprised at how small this amplifier is for the SPL it can produce. I have some monos and they sound as good as advertised.

The Anaview amp I have is already Class D, it is 500 watt per channel into 2 ohm but 300 watt into 4 ohm. The module is pretty small already!
The purifi looks more powerful and cleaner which is interesting.

 

[anphex]

My babys arrived yesterday!

I just had to open them while still at work to check if everything was in order and to see if my preferred gain setting was considered. I was surprised as the build quality is top notch. The wiring is flawless and they meticulously took care of the heat management with pads and offset placing of the vents so the air passes from the bottom front to top back. Remember: the DIY kit of the Hypex just left the parts in there without real connection to the case. My module ran pretty hot compared to the case itself when I checked it

They are pretty long compared to Hypex NC400 DIY amps which are wider and shorter.

As for the first hours of listening, my (maybe full placebo) verdict: they are noticable more transparent than the Hypex amps, "smoother" as I call it. The reason for this might also just be that I can drive my SMLS SU-9N far louder (at level 80) and getting SINAD for free due to the reduced gain.
The SMSL DAC with the max Vrms of 4,8 is more than enough to even drive my inefficient Nubert speakers (85dB/1W) to huge levels, including a bass boost/loudness curve.

For now, I can wholeheartedly recommend these bad boys. It's endgame amp wise. Though I don't like the bright light at the front of the amps when they are turned on. I might put black tape over it sooner or later haha. Here are some pics.

Edit: Oh, an no coil or capacitor noise whatsever. Also no noise in the signal itself. It's absolutely silent and clean.

 

[fourdogslong]

My babys arrived yesterday!

I just had to open them while still at work to check if everything was in order and to see if my preferred gain setting was considered. I was surprised as the build quality is top notch. The wiring is flawless and they meticulously took care of the heat management with pads and offset placing of the vents so the air passes from the bottom front to top back. Remember: the DIY kit of the Hypex just left the parts in there without real connection to the case. My module ran pretty hot compared to the case itself when I checked it

They are pretty long compared to Hypex NC400 DIY amps which are wider and shorter.

As for the first hours of listening, my (maybe full placebo) verdict: they are noticable more transparent than the Hypex amps, "smoother" as I call it. The reason for this might also just be that I can drive my SMLS SU-9N far louder (at level 80) and getting SINAD for free due to the reduced gain.
The SMSL DAC with the max Vrms of 4,8 is more than enough to even drive my inefficient Nubert speakers (85dB/1W) to huge levels, including a bass boost/loudness curve.

For now, I can wholeheartedly recommend these bad boys. It's endgame amp wise. Though I don't like the bright light at the front of the amps when they are turned on. I might put black tape over it sooner or later haha. Here are some pics.

Edit: Oh, an no coil or capacitor noise whatsever. Also no noise in the signal itself. It's absolutely silent and clean.

Nice!
The wiring job looks better than what they show on the website, that's good news.
Maybe you could ask audiophonics if there's a hack to dim the front led, maybe put a resistor in there or something...

Thanks for sharing.

 

[anphex]

I am 100 % sure they are reading this here and maybe they'll share something so the whole community can benefit.
If they were reddish or orange I wouldn't mind but it just HAD to be this bright blue led light that gets really annoying in the evening and night when it's dark.

 

[delgesu]

can´t wait to get mine .... can´t wait to get mine ....
they really look far better inside than the pictures on their homepage.

 

[mglobe]

My babys arrived yesterday!

I just had to open them while still at work to check if everything was in order and to see if my preferred gain setting was considered. I was surprised as the build quality is top notch. The wiring is flawless and they meticulously took care of the heat management with pads and offset placing of the vents so the air passes from the bottom front to top back. Remember: the DIY kit of the Hypex just left the parts in there without real connection to the case. My module ran pretty hot compared to the case itself when I checked it

They are pretty long compared to Hypex NC400 DIY amps which are wider and shorter.

As for the first hours of listening, my (maybe full placebo) verdict: they are noticable more transparent than the Hypex amps, "smoother" as I call it. The reason for this might also just be that I can drive my SMLS SU-9N far louder (at level 80) and getting SINAD for free due to the reduced gain.
The SMSL DAC with the max Vrms of 4,8 is more than enough to even drive my inefficient Nubert speakers (85dB/1W) to huge levels, including a bass boost/loudness curve.

For now, I can wholeheartedly recommend these bad boys. It's endgame amp wise. Though I don't like the bright light at the front of the amps when they are turned on. I might put black tape over it sooner or later haha. Here are some pics.

Edit: Oh, an no coil or capacitor noise whatsever. Also no noise in the signal itself. It's absolutely silent and clean.

Mine are supposed to arrive tomorrow, though I think UPS is optimistic.