Audiophonics HPA-S400ET Review (Stereo Amplifier)

[JensenW]

Just received my HPA S-400 amplifier. I found there is noise coming from all the capacitors of the amplifier, i.e. on both the Purifi modules and the Hypex Power Module, when I put my ear close to the case. It is soft enough to be inaudible at about 30cm distance from the machine. It occurs when connected to power (with the power button turned off) while being connected to nothing else. It does not cease with the use of an isolation transfomer. The amp is the only thing that is plugged into this wall plug.

I noticed it because my XLR cable got stuck in the amp's input and I am unable to get my cable out. The release spring-push button seems not springy, perhaps broken inside. Not a very smooth start though I must say, the sound coming out from it was very transparent, which is something I need.

Do other Audiophonics amp owners get this capacitor noise issue/ quality control problems too?

 

[HansHolland]

Just received my HPA S-400 amplifier. I found there is noise coming from all the capacitors of the amplifier, i.e. on both the Purifi modules and the Hypex Power Module, when I put my ear close to the case. It is soft enough to be inaudible at about 30cm distance from the machine. It occurs when connected to power (with the power button turned off) while being connected to nothing else. It does not cease with the use of an isolation transfomer. The amp is the only thing that is plugged into this wall plug.

I noticed it because my XLR cable got stuck in the amp's input and I am unable to get my cable out. The release spring-push button seems not springy, perhaps broken inside. Not a very smooth start though I must say, the sound coming out from it was very transparent, which is something I need.

Do other Audiophonics amp owners get this capacitor noise issue/ quality control problems too?

inductor?

Can't answer your question, have no Audiophonics/Hypex/Purifi

 

[amarsicola]

Just received my HPA S-400 amplifier. I found there is noise coming from all the capacitors of the amplifier, i.e. on both the Purifi modules and the Hypex Power Module, when I put my ear close to the case. It is soft enough to be inaudible at about 30cm distance from the machine. It occurs when connected to power (with the power button turned off) while being connected to nothing else. It does not cease with the use of an isolation transfomer. The amp is the only thing that is plugged into this wall plug.

I noticed it because my XLR cable got stuck in the amp's input and I am unable to get my cable out. The release spring-push button seems not springy, perhaps broken inside. Not a very smooth start though I must say, the sound coming out from it was very transparent, which is something I need.

Do other Audiophonics amp owners get this capacitor noise issue/ quality control problems too?

You should be able to return it for free within 2 weeks from purchase date. I wouldn't insist with repairing what is born weird. I am sorry you were unlucky.
Then you can give Audiophonics another try, go for a better manufactured Boxem amp, or wait few weeks for the new NCOREx DYI kit that on paper is even better than purify.
If two weeks are over, Audiophonics is known to have a good customer service anyway, and they take care for their reputation in this forum

 

[ex audiophile]

Just received my HPA S-400 amplifier. I found there is noise coming from all the capacitors of the amplifier, i.e. on both the Purifi modules and the Hypex Power Module, when I put my ear close to the case. It is soft enough to be inaudible at about 30cm distance from the machine. It occurs when connected to power (with the power button turned off) while being connected to nothing else. It does not cease with the use of an isolation transfomer. The amp is the only thing that is plugged into this wall plug.

I noticed it because my XLR cable got stuck in the amp's input and I am unable to get my cable out. The release spring-push button seems not springy, perhaps broken inside. Not a very smooth start though I must say, the sound coming out from it was very transparent, which is something I need.

Do other Audiophonics amp owners get this capacitor noise issue/ quality control problems too?

I have one on order and will report back if there's an issue. Almost cancelled and ordered Boxem but the latter is a couple hundred more, no power cable included (weird).

 

[JensenW]

You should be able to return it for free within 2 weeks from purchase date. I wouldn't insist with repairing what is born weird. I am sorry you were unlucky.
Then you can give Audiophonics another try, go for a better manufactured Boxem amp, or wait few weeks for the new NCOREx DYI kit that on paper is even better than purify.
If two weeks are over, Audiophonics is known to have a good customer service anyway, and they take care for their reputation in this forum

When I purchased it, it was out of stock. It was back in stock on day 10 and I received it finally on Day 13 (today) from my purchase date. It's not fair to start counting the 14 days from the purchase date in this case, when they have a good customer who was willing to pay first and put trust in the company. I have to work it out with Audiophonics if I decide to return and refund. I have heard of their good reputation.

Just read the measurements of the Boxem amp on ASR, apparently the Boxem measures significantly less well than the Audiophonics implementation. I was attracted towards the Audiophonics because of its really excellent measurements.

BTW, any Audiophonics amp owners could kindly put their ears to the machine and share if you hear any capacitor noise when power is connected? Thanks!

 

[darkless]

In EU you have 14 days to return an item from the day you received it.

 

[JensenW]

In EU you have 14 days to return an item from the day you received it.

Thanks for the clarification. I'm a few thousand miles from Europe. But I believe the EU vendor/ sales regulations should apply when the vendor is in EU regardless of where the customer resides?

 

[hiphop_odc]

I have the monoblocks and they are silent.

 

[RandomEar]

When I purchased it, it was out of stock. It was back in stock on day 10 and I received it finally on Day 13 (today) from my purchase date. It's not fair to start counting the 14 days from the purchase date in this case, when they have a good customer who was willing to pay first and put trust in the company. I have to work it out with Audiophonics if I decide to return and refund. I have heard of their good reputation.

Just read the measurements of the Boxem amp on ASR, apparently the Boxem measures significantly less well than the Audiophonics implementation. I was attracted towards the Audiophonics because of its really excellent measurements.

BTW, any Audiophonics amp owners could kindly put their ears to the machine and share if you hear any capacitor noise when power is connected? Thanks!

The Boxem unit tested here is of a totally different design than the HPA-S400ET. Therefore, it's not really fair to say that it measures worse - the Boxem Purifi amp will most likely be on par with the Audiophonics one. Concerning the buzzing, it is a rare but known issue with Hypex all-in-one modules:

Do NCore have buzzing noise?

Hi, On Audiophonics, on the page for the PA-250NC, there are two customer comments (in french) about a buzzing noise coming from the module, even when it is off: https://www.audiophonics.fr/fr/ampl...-13545.html One customer thinks it's a bit annoying, another writes it is faint and only...

www.audiosciencereview.com

It's probably coming from the SMPS section, so it doesn't surprise me that the Audiophonics Purifi units with Hypex SMPS can be affected, too.

 

[EdW]

Just read the measurements of the Boxem amp on ASR, apparently the Boxem measures significantly less well than the Audiophonics implementation. I was attracted towards the Audiophonics because of its really excellent measurements.

The ASR measurements I found were for the much less expensive and lower powered BoXem ARTHUR 2408/N2 with Hypex NC122MP stereo amp module. The fair comparison would be with the ARTHUR 3215/E2 Purifi based stereo amp for which there is no ASR review. It should be broadly comparable to the Audiophonics Purifi implementation, but also includes auto on/off and clip indicator. I’d like to see the 4215/E2 reviewed as BoXem build quality looks superb.

EDIT. Just noticed that @RandomEar made a similar observation a minute or two before me!

 

[JensenW]

Concerning the buzzing, it is a rare but known issue with Hypex all-in-one modules:

Do NCore have buzzing noise?

Hi, On Audiophonics, on the page for the PA-250NC, there are two customer comments (in french) about a buzzing noise coming from the module, even when it is off: https://www.audiophonics.fr/fr/ampl...-13545.html One customer thinks it's a bit annoying, another writes it is faint and only...

www.audiosciencereview.com

It's probably coming from the SMPS section, so it doesn't surprise me that the Audiophonics Purifi units with Hypex SMPS can be affected, too.

Seems that quite a lot of people noticed the noise. But some units could be completely silent. Someone mentioned that DC offset has no effect on the modules, so a DC blocker will not be useful, and thus running it through my isolation transformer had no effect at all.

The ASR measurements I found were for the much less expensive and lower powered BoXem ARTHUR 2408/N2 with Hypex NC122MP stereo amp module. The fair comparison would be with the ARTHUR 3215/E2 Purifi based stereo amp for which there is no ASR review. It should be broadly comparable to the Audiophonics Purifi implementation, but also includes auto on/off and clip indicator. I’d like to see the 4215/E2 reviewed as BoXem build quality looks superb.

EDIT. Just noticed that @RandomEar made a similar observation a minute or two before me!

I wonder if any Boxem users found their units making electrical noise like the Audiophonics ones?

 

[EdW]

I wonder if any Boxem users found their units making electrical noise like the Audiophonics ones?

you would think so unless BoXem checks for noisy modules and exchanges any that are audible.
Interestingly March audio are not using Hypex SMPS In their Purifi amps. Their SMPS is universal 100-240V without a jumper so is probably stabilised against mains fluctuations.

 

[Rantenti]

I have the monoblocks and they are silent.

May I ask which model are your monoblocks?

 

[hiphop_odc]

May I ask which model are your monoblocks?

MPA-M400ET
FAB-9644-001
I just unplugged one of them and took to another room.
Plugged it in there and when I press my ear to the vent holes, I can hear a little bit humming. But a inch away I can't hear it.

 

[Rantenti]

MPA-M400ET
FAB-9644-001
I just unplugged one of them and took to another room.
Plugged it in there and when I press my ear to the vent holes, I can hear a little bit humming. But a inch away I can't hear it.

Ah, then it seems it is not a rare or isolated scenario that there is acoustic noise from the machines.

Some manufacturers claim their amps are completely silent, and not "having a very low acoustic noise level".

While the amount of noise does not impair listening experience at an 8 feet distance, but it may pose problems in near field listening in a dead silent room.

I enjoyed the power and transparency of the amp, I just wonder what is causing the noise in their implementation, while other Purifi amp manufacturers claim theirs are completely silent.

 

[tmtomh]

Could it possibly be a particular batch of components in the psu or something? My Audiophonics amp from May 2020 is electrically and mechanically silent, and I haven’t heard about mechanical noise from any Purifi-based amp until now.

 

[kenshone]

Ah, then it seems it is not a rare or isolated scenario that there is acoustic noise from the machines.

Some manufacturers claim their amps are completely silent, and not "having a very low acoustic noise level".

While the amount of noise does not impair listening experience at an 8 feet distance, but it may pose problems in near field listening in a dead silent room.

I enjoyed the power and transparency of the amp, I just wonder what is causing the noise in their implementation, while other Purifi amp manufacturers claim theirs are completely silent.

I would use a decent pair of active studio monitors, or a Topping amplifier if my use case was near-field listening.

That being said, there's no excuse for a buzzing noise on some amps. Hopefully they fix this for you.

 

[nemesis.ie]

I think low amplifier gain is a good trade off as it is easier to build a lower noise DAC and all upstream noise will be multiplied by the amplifier so better to keep the amplifier gain low as practicable.

Personally I wish manufacturers used lower gains especially on equipment with balanced inputs. 20 dB of gain (medium gain setting here) is perfect for 4 V input, can drive to full power with a little room to spare.

I think part of the resistance to using lower gain is that to an uneducated consumer it does not sound as loud with the same input which they attribute to being less powerful.

Michael

Agreed, My (very nice and silent until then) Emotiva amps now produce horrible tweeter hiss when paired with an Altitude 32. I used some 20dB (10 or 15 barely helped) attenuators which helped a bit but the hiss is still there and some speakers are a bit close.

Variable gain (even two options) on all amps would be nice or indeed if the preamp makers made it an option too. Then we could all dial in the optimum settings for our needs.

I'm getting in a 4 channel Audiophonics Purifi unit to see if it fixes it - my back will also thank me I think.

 

[JensenW]

I would use a decent pair of active studio monitors, or a Topping amplifier if my use case was near-field listening.

That being said, there's no excuse for a buzzing noise on some amps. Hopefully they fix this for you.

Yes, I am in contact with Audiophonics now. Here's a photo showing the setup completely not attached to anything. The circled areas are the areas where the sounds are coming from.

1. Power cable UNplugged: no noise of course.
2. Power cable plugged in + power button OFF: noise +ve nearly immediately after power cable plugged in
3. Power cable plugged in + power button pressed ON: noise +ve (same)

The noise is a series of soft approx 50Hz buzzing with intermittent electrical "cracking" sounds, which are also very soft (audible within 10 cm of the capacitors). I have a recording of the sound to make sure I am not imagining things and a technician friend noted the "electrical"-sounding noise and said it shouldn't normally occur.

The capacitor noise stops after about 10 seconds after the unit is unplugged.

Audiophonics said it was impossible for the capacitors to create noise when the power button is off but yet I was there, and I heard it. I repeated the test a few times, the results were reproducible 100%. I leave this puzzle to the collective minds of our ASR friends who may suggest a possible explanation.

I have other amps at my place and they were completely silent, no matter plugged in, switched off, switched on, or working.

 

[bkdc]

Probably a bad batch of components. There is nothing in the build or wiring that should cause a noise.