Audiophonics HPA-S400ET Review (Stereo Amplifier)

[pogo]

All of them use the same module and therefore should perform the same.

This is not quite correct. I don't know any other implementation that provides such power at 2 ohms as the M23 or M33 (not bridged): Link

 

[Satyadhara]

Yesterday I noticed by chance that the amp emits a relatively low-level, but still audible (when putting my ear right next to the amp) high-pitched "whining" noise when switched off. When I turn the amp on, this noise stops and is replaced by a lower-frequency noise, again not very high in level. Nothing major, but I was wondering what's going on there and if there is any way to get rid of it altogether?

 

[Vincentponcet]

This is not quite correct. I don't know any other implementation that provides such power at 2 ohms as the M23 or M33 (not bridged): Link

It sounds like NAD added more caps on the power supply input board. But didn't change the amp itself.

 

[pogo]

There is more than that, see also here: Link

 

[Vincentponcet]

There is more than that, see also here: Link

I was saying this about this.
The green one is like the purifi amp board, except the PCB is green instead of blue for the standard OEM one, and the brand of the cap is different.
But their input board has a lot of caps on the power rail, to support more sustained peak power, and might help for lower impedance speakers.

NAD M28 7 Channel Purifi Amplifier Teardown

I recently reviewed the NAD M28 multichannel amplifier based on Purifi modules. As promised, this is a tear down of the unit with kind permission of the owner. The amp was a delight to open with beautiful screws holding the attractive top down. Once removed, we are greeted to a nice and...

www.audiosciencereview.com

There is also the large heatsinks on the back of the modules.

Purifi says

The supply should be designed such that each rail has enough thermal headroom to drive full peak power for a minimum of one half-period of the lowest desired audio frequency or as otherwise required for continuous power delivery as determined by the system integrator. The 1ET400A design limits power delivery only if OCP or OTP events are triggered and in practice, especially in multichannel applications, the power supply often is the limiting factor for sustained power delivery.

https://purifi-audio.com/wp-content/uploads/2020/01/1ET400A-Data-Sheet-1.00.pd#page=12

7.2 Thermal Requirements
While 1ET400A has very low idle losses and high overall efficiency, adequate cooling is essential for sustained power delivery. Careful considerations must be given to design of the thermal system in order to achieve desired output power specifications. It is recommended to mount the module on a heatsink, e.g., an adequately design aluminum chassis.

https://purifi-audio.com/wp-content/uploads/2020/01/1ET400A-Data-Sheet-1.00.pd#page=23



So NAD did their job on the input + amp boards to support low impedance, sustained high power.
Sadly, they didn't do the job on preserving the SINAD of the amp module.

 

[nemesis.ie]

Yesterday I noticed by chance that the amp emits a relatively low-level, but still audible (when putting my ear right next to the amp) high-pitched "whining" noise when switched off. When I turn the amp on, this noise stops and is replaced by a lower-frequency noise, again not very high in level. Nothing major, but I was wondering what's going on there and if there is any way to get rid of it altogether?

SMPS idle whine probably. A lot of phone chargers are really bad for that so I can't have them in the bedroom, but the Audiophonics seem to be at a very low level in this respect and I usually have them on when in the cinema room.

I also have them powering off physically when not in use via triggers so it's never an issue.

 

[LugsyTL47]

I was going to order to ON, but since they only use the UPS, I went with Buckeye amps. Previously, UPS/Fedex charged me an enormous additional fees for customs clearance on top of 13%HST.

I’m considering Buckeye NC252. What approx customs fees to ON could I expect?

 

[bobitto]

I’m considering Buckeye NC252. What approx customs fees to ON could I expect?

Dylan sends it using regular postage or UPS. So via USPS and Canada Post I paid only about $200 CAD duties as he valued the amps a bit cheaper. I’m saying “only” because I ordered 8ch 252 and 6ch 502. Good luck

 

[Axel Endriss]

because it might be helpful for others who are thinking about this amp:
I recently got Audiophonics' HPA-S400ET. It replaces Allo's Volt+ D in my chain with Allo's Piano 2.1/Kali, Linn Wakonda as preamp, and a pair of Focal Temptation. Finding #1 is that it actually sounds audibly better to me with Audiophonics' HPA-S400ET, even though the sound with the Volt+ D was really great before (would say 99.x now when it was 95 out of 100 before). Finding #2 is that a TV plugged into a different outlet in the same room creates a hum that I didn't have before. The hum is gone as soon as I unplug the cable from the TV. The amazing thing is that this is completely independent of whether I have anything connected to the amplifier input or not. I.e. even without any input signal I have a hum on the speakers as soon as the TV is connected to the cable connection. Interestingly (for me) this is only true when I set the amplifier input to RCA. On balanced it is as quiet as a mouse, as it should be.

 

[pogo]

What kind of TV is this (plasma, ...)?
Wow, are your Temptations still running in their original condition?
I replaced mine 30 years ago, but I still remember it well

 

[Audiophonics]

Here's a fresh video review from Mike audio

 

[Sokel]

because it might be helpful for others who are thinking about this amp:
I recently got Audiophonics' HPA-S400ET. It replaces Allo's Volt+ D in my chain with Allo's Piano 2.1/Kali, Linn Wakonda as preamp, and a pair of Focal Temptation. Finding #1 is that it actually sounds audibly better to me with Audiophonics' HPA-S400ET, even though the sound with the Volt+ D was really great before (would say 99.x now when it was 95 out of 100 before). Finding #2 is that a TV plugged into a different outlet in the same room creates a hum that I didn't have before. The hum is gone as soon as I unplug the cable from the TV. The amazing thing is that this is completely independent of whether I have anything connected to the amplifier input or not. I.e. even without any input signal I have a hum on the speakers as soon as the TV is connected to the cable connection. Interestingly (for me) this is only true when I set the amplifier input to RCA. On balanced it is as quiet as a mouse, as it should be.

If in europe try plug it to the outlet in the opposite way too and see if that fixes it.

 

[Axel Endriss]

What kind of TV is this (plasma, ...)?
Wow, are your Temptations still running in their original condition?
I replaced mine 30 years ago, but I still remember it well

TV is nothing special, it's a normal LCD TV from Samsung (~6 years old). Also it doesn't matter whether it's switched on or not. The hum is there when the tv is connected to the tv cable. What I don't understand is that the hum is there even there's nothing connected to the input of the amp. So somehow the ground loop at the tv "talks" via AC power grid of the house and the amo doesn't like it (?).

My Temptations received new beading on the bass speakers and tweeters 6 years ago and thus sound like the first day again. I like the speakers a lot and would probably have to dig deep into my pocket to get comparable speakers today. I have compared them to other speakers several times over the years, but always gave my old ones the edge.

 

[Caliban]

TV is nothing special, it's a normal LCD TV from Samsung (~6 years old). Also it doesn't matter whether it's switched on or not. The hum is there when the tv is connected to the tv cable. What I don't understand is that the hum is there even there's nothing connected to the input of the amp. So somehow the ground loop at the tv "talks" via AC power grid of the house and the amo doesn't like it (?).

My Temptations received new beading on the bass speakers and tweeters 6 years ago and thus sound like the first day again. I like the speakers a lot and would probably have to dig deep into my pocket to get comparable speakers today. I have compared them to other speakers several times over the years, but always gave my old ones the edge.

You need something like this :

Cable antenna ground isolator | MadBoy Premium Karaoke Systems | Webshop

Erottaa television maan antenniverkon maasta. Ilman maaerotinta antennin ja karaokelaitteiden maiden potentiaalierot voivat aiheuttaa kaiuttimiin hurinaa.

www.madboy-audio.com

 

[Axel Endriss]

You need something like this :

Cable antenna ground isolator | MadBoy Premium Karaoke Systems | Webshop

Erottaa television maan antenniverkon maasta. Ilman maaerotinta antennin ja karaokelaitteiden maiden potentiaalierot voivat aiheuttaa kaiuttimiin hurinaa.

www.madboy-audio.com

Thx Caliban, this is a good hint!

 

[Axel Endriss]

Another question related to the HPA-S400ET: Have you tried the different gain settings and could you hear a difference?

 

[tmtomh]

Another question related to the HPA-S400ET: Have you tried the different gain settings and could you hear a difference?

I've tried medium and high gain. Zero difference (except the gain level of course!)

 

[nemesis.ie]

As mentioned previously, bypass got rid of my tweeter hiss.

 

[Snoopy]

Just saw audiophonics has integrated amps now. Ncore + ESS9038Q2.

What's the opinion on this ?

AUDIOPHONICS DAW-S250NC Class D Integrated Amplifier NCore DAC ES9038Q2M WiFi Bluetooth 5.0 2x250W 4 Ohm 32bit 768kHz DSD256 - Audiophonics

Versatile and powerful, we offer you with the DAW-S250NC a real integrated and connected amplifier to which you can add speakers to enjoy your music in the best possible way...

www.audiophonics.fr

 

[Bleib]

Just saw audiophonics has integrated amps now. Ncore + ESS9038Q2.

What's the opinion on this ?

AUDIOPHONICS DAW-S250NC Class D Integrated Amplifier NCore DAC ES9038Q2M WiFi Bluetooth 5.0 2x250W 4 Ohm 32bit 768kHz DSD256 - Audiophonics

Versatile and powerful, we offer you with the DAW-S250NC a real integrated and connected amplifier to which you can add speakers to enjoy your music in the best possible way...

www.audiophonics.fr

That it would be great to see measurements