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Audiophonics HPA-S400ET Review (Stereo Amplifier)

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Caliban

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FWIW, in standby mode, my Kilowatt is showing an idle power consumption of 16.8 Watts for my Audiophonics amp.
boXem have done a better job in that aspect with their counterpart 4215/E2, they state a standby consumption below 0.5 Watts.
Something to think about now when the price for electricity is rising incredibly (at least in Europe)
 

Caliban

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KMO

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"FWIW, in standby mode"..
"idle power consumption"

How to confuse people...

And I immediately assumed we're talking idle, not standby, because 16.8 watts is a bit on the high side even for idle. If that's supposed to be standby, I'd say it's faulty.
 

nemesis.ie

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Indeed, my mix of 4ch, 2ch and 1ch all pull around 8W in *IDLE* per channel - so a 2ch one is indeed around 16W. i.e. powered on with no signal - in standby it's massively less.
Per their web site the trigger modules use 0.36W ... not sure if that is when energised (quite likely) or not. So when the unit is "untriggered" it could be even less. "operating current" says 33mA which is under 0.5W ...

So no @Caliban I don't see evidence of Boxem having done better here. I also use an Audiphonics trigger modules to control a strip with 5 amp channels connected (2000W max (which never happens) and is under the strip's rating) so that's <1/2W standby for 5 channels.

The OP's comment has to be read more carfully "standby in idle" i.e. on but without a signal "standing by for a signal" rather than "powered down standby".

For context an Emotiva A/B amp pulls 30W/ch in idle with a linear PSU and 20W for their SMPS models (monoblocks).


I suspect this actually used 0 at standby. ;)
 
Last edited:

Redwine

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Why should I choose

Audiophonics HPA-S400ET or Boxem among others​

instead of a NAD C 298?

are there any good arguments apart from case design and price difference?
 

nemesis.ie

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Price and case are both good reasons and the choice comes down to you. I like the neater cases of the Audiphonics and saving money.

Other than that, you need to look at the measurements and see if there are differnces there that are pertinent to you.

Externally switchable gain may be of interest too, although usually once it's set, that's it for many years.
 

Redwine

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Price and case are both good reasons and the choice comes down to you. I like the neater cases of the Audiphonics and saving money.

Other than that, you need to look at the measurements and see if there are differnces there that are pertinent to you.

Externally switchable gain may be of interest too, although usually once it's set, that's it for many years.
So in terms of sound quality, they should be the same?
 

nemesis.ie

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If the measurements are similar/noise etc. below the threshold of hearing, probably.

I've 0 regrets with the Audiphonics and could not have justified 2x+ the price for the 16 channels I have. You can buy a LOT of GREAT subwoofers for the saved money. ;)
 

TheWalkman

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"idle power consumption"

How to confuse people...

And I immediately assumed we're talking idle, not standby, because 16.8 watts is a bit on the high side even for idle. If that's supposed to be standby, I'd say it's faulty.
Idle mode.

(Forgive me for my transgressions.)
 

Caliban

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Idle mode.

(Forgive me for my transgressions.)
Aha, ok, do you have the possibility to measure its current consumption with trigger input off ? Provided your amplifier version has a trigger input that is.
No need for a measurement if you are using an external trigger device like the one @nemesis.ie are talking about.
 
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TheWalkman

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Aha, ok, do you have the possibility to measure its current consumption with trigger input off ? Provided your amplifier version has a trigger input that is.
No need for a measurement if you are using an external trigger device like the one @nemesis.ie are talking about.
Unfortunately, I’m not triggering the amp externally so I won’t be able to measure this. Perhaps someone else can.
 

Caliban

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Unfortunately, I’m not triggering the amp externally so I won’t be able to measure this. Perhaps someone else can.
It is not deadly important, I was just a bit surprised by what I thought was a high standby power consumption.
>17 Watts powered on and in idle does not sound unreasonable to me (too lazy to check data sheet..)
 
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nemesis.ie

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It is indeed reasonable or idle, as mentioned compared to e.g. class AB/linear PSUs.

Two channels of an AB might be pulling 60W idle power ...

I might have a chance to do some measurements next week, I have 3 different models.
 

KMO

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It is not deadly important, I was just a bit surprised by what I thought was a high standby power consumption.
>17 Watts powered on and in idle does not sound unreasonable to me (too lazy to check data sheet..)
It's a tad high from the specs, but I guess it's about right.

Power supply loss is specced at 9W typical, and each 1ET400A module should be 1.7W, plus 0.4W for the trigger module, so that's 12.8W.

So that's 4 watts left over for input buffers and LEDs.
 

Lagerfeldt

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Buying experience
I ordered the Audiophonics HPA-S400ET Sparkos Edition a couple of weeks ago. It was out of stock at the time of order, but I was promised a 15 day lead time.

My buying experience with Audiophonics was very good: detailed and instant replies to my questions, and updates on the shipment (1 day UPS shipping from France to Denmark). I was able to purchase B2B with my VAT no.

Setup
B&W 802 Diamond speakers, [insert amp here], Trinnov ST2 Pro correction hardware, Imperium monitor controlller, Lynx HiLo DAC.

Current Classé CA-2300 Delta
My current amp was a Classé CA-2300 Delta, Class A/B. Purchased for approx. 52.000 DKK (EUR €7.000 / USD $7,000) in 2013. The left side blew something recently and I had to get it serviced for a whopping €/$1,345.

The Classé sounds great, lots of power, very clean. It uses quite a bit of electricity in idle mode and has a quiet fan that rarely gets to spin up. I don't put my amps into standby as I use them every day in the studio at random times.

Loaner NAD C298
I got a brand new NAD C298 on loan, but it didn't sound right to me.

Most likely it's simply me being used to different (Class A/B) amp for many years. The low end felt lower and less solid with the C298, the midrange (perhaps as an indrect result) more pronounced compared to the Classé.

Another explanation for my dislike could be a technical mismatch, namely that the still active Trinnov ST2 Pro profile was based on the Classé and it not matching the C298. Or it could be psychoacoustical: the C298 might be more precise; but cleaner also means less perceived sub frequencies due to lower harmonic distortion than what I was used to.

The C298 pulled up a very low level hiss even when turning down the gain to the minimum setting or when using the fixed setting - I wasn't able to find a way to remove the hiss.

The annoying auto-sense can be shut off, fortunately, but I didn't bother for the two weeks I had it on loan.

New HPA-S400 ET Sparkos Edition
With the HPA I was able to set the jumpers to bypass the gain. To match the bypass setting, I changed the jumpers in my Lynx HiLo DAC on the isolated monitor output from -11 dBu to -24 dBu to ramp up the voltage. This allowed me to reduce the hiss to an inaudible level and have plenty of power.

Nice case and neatly done inside. Everything looked stellar. All torques screws had equal pressure, which satisfied my OCD.

Unlike the C298 the HPA-S400 ET sounded right in the low end, which contradicted my inital assumption that the Trinnov profile could be the culprit. Since the HPA-S400ET measures even better than the C298 then psychoacoustics aren't to blame either. So either it's good old placebo or confirmation bias, or the C298 I have on loan is a bit off from the factory.

I decided to hire the same external consultant I used in 2015 to help me make a new Trinnov measurement for the HPA. Same room, same speakers, same monitor controller, same studio console, same measurement mic, same guy(s). The Trinnov 3D measurement mic was placed using a gyro laser level. This allowed us to get the same placement ± a few mm in the sweet spot.

The differences in the measurements between the Classé and the HPA were small or inconclusive, but then again an acoustical measurement is a different beast since there are many variables. The largest difference was around 10 kHz where there was a ±1.25 dB between the two amps in the same setup, withe HPA having more energy there. Obviously I can't tell which is "correct" - only that there's a difference.

We did several additional measurements between 0 and 40 cms on the Z-axis and they all confirmed a variation in this frequency area, so it's not acoustical, i.e. not due to a difference in mic placement between the two amps. It will make the HPA sound a bit more sparkly compared to the Classé or vice versa, if you will.

I'm saving on electricty with the HPA, about €/$399 a year (Danish energy prices are crazy), so I'm probably buying another HPA (non-Sparkos) to replace another old Class A/B amp. That's a big bonus you can tell yourself (or your wife) when switching out ye olde Class A/B for a brand new Class D.

One criticism is that the HPA doesn't come with any kind of manual or even a piece of instruction paper, but that's what Google is for. Also, the heat sinks on the sides of the unit can resonate at high frequencies. I'm not sure if that's a real life issue at 3 meters listening distance, but I'm thinking about dampening them somehow. Last thing: the power on LED is quite bright and can't easily be dimmed.
 
Last edited:

Caliban

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Buying experience
I ordered the Audiophonics HPA-S400ET Sparkos Edition a couple of weeks ago. It was out of stock at the time of order, but I was promised a 15 day lead time.

My buying experience with Audiophonics was very good: detailed and instant replies to my questions, and updates on the shipment (1 day UPS shipping from France to Denmark). I was able to purchase B2B with my VAT no.

Setup
B&W 802 Diamond speakers, [insert amp here], Trinnov ST2 Pro correction hardware, Imperium monitor controlller, Lynx HiLo DAC.

Current Classé CA-2300 Delta
My current amp was a Classé CA-2300 Delta, Class A/B. Purchased for approx. 52.000 DKK (EUR €7.000 / USD $7,000) in 2013. The left side blew something recently and I had to get it serviced for a whopping €/$1,345.

The Classé sounds great, lots of power, very clean. It uses quite a bit of electricity in idle mode and has a quiet fan that rarely gets to spin up. I don't put my amps into standby as I use them every day in the studio at random times.

Loaner NAD C298
I got a brand new NAD C298 on loan, but it didn't sound right to me.

Perhaps it's simply me being used to different (Class A/B) amp for many years. The low end felt lower and less solid with the C298, the midrange (perhaps as an indrect result) more pronounced compared to the Classé.

I figured it was either due to a technical mismatch, namely that the still active Trinnov ST2 Pro profile was based on the Classé and it not matching the C298 or it could also be purely psychoacoustical: the C298 might be more precise; but cleaner also means less perceived sub frequencies due to lower harmonic distortion.

The C298 pulled up a very low level hiss even when turning down the gain to the minimum setting or when using the fixed setting - I wasn't able to find a way to remove the hiss.

The annoying auto-sense can be shut off, fortunately, but I didn't bother for the two weeks I had it on loan.

New HPA-S400 ET Sparkos Edition
With the HPA I was able to set the jumpers to bypass the gain. To match the bypass setting, I changed the jumpers in my Lynx HiLo DAC on the isolated monitor output from -11 dBu to -24 dBu to ramp up the voltage. This allowed me to reduce the hiss to an inaudible level and have plenty of power.

Nice case and neatly done inside. Everything looked stellar.

Unlike the C298 the HPA-S400 ET sounded right in the low end, which contradicted my inital assumption that the Trinnov profile could be the culprit. Since the HPA-S400ET measures even better than the C298 then psychoacoustics aren't to blame either. So either it's placebo or confirmation bias, or the C298 I have on loan is a bit off from the factory.

I decided to hire the same external consultant I used in 2015 to help me make a new Trinnov measurement for the HPA. Same room, same speakers, same monitor controller, same studio console, same measurement mic, same guy(s). The Trinnov measurement mic was placed using a gyro laser level. This allowed us to get the same placement ± a few mm in the sweet spot.

The differences in the measurements between the Classé and the HPA were small, but then again an acoustical measurement is a different beast as there are many variables. The biggest difference was around 10 kHz where the Classé was less pronounced/the HPA more pronounced. ±1.25 dB between the two amps in the same setup. Obviously I can't tell which is "correct" - only that there's a difference.

We did several additional measurements between 0 and 40 cms on the Z-axis and they all confirmed a difference in this frequency area, so it's not acoustical, i.e. not due to a difference in mic placement between the two amps. It will make the HPA sound a bit more sparkly compared to the Classé or vice versa, if you will.

I'm saving on electricty with the HPA, about €/$399 a year (Danish energy prices are crazy), so I'm probably buying another HPA (non-Sparkos) to replace another old Class A/B amp. That's a big bonus you can tell yourself (or your wife) when switching out ye olde Class A/B for a brand new Class D.

One criticism is that it doesn't come with any kind of manual or even a piece of paper, but that's what Google is for. Also, the heat sinks on the sides of the unit can resonate at high frequencies. I'm not sure if that's a real life issue, but I'm thinking about dampening them somehow. Last thing: the power on LED is quite bright and can't easily be dimmed.

Great read, NAD C298 is off the list then...I will certainly hear the hiss too, having my speakers close to me, no need to even try it..
Nice to see a Hilo user, are you satisfied with it ?
 

Lagerfeldt

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Thanks! I asked Purifi about the C298 and they told me that the NAD M23 measures better than the C298 and the M33, but I don't see the argument for an M23 over the HPA-S400ET in any case.

Yes, as a mastering grade sound card/ADC/2 x DAC with extensive internal routing options the HiLo has been a market leader for years. I think it was or is still around $3,500 or $3,000 + Thunderbolt card in my case.

If I didn't need the AD and dual DAC and routing options I'd get a Topping D90SE or an RME ADI-2 DAC FS, but the latter is missing an AES/EBU XLR input.
 

Matias

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Thanks! I asked Purifi about the C298 and they told me that the NAD M23 measures better than the C298 and the M33, but I don't see the argument for an M23 over the HPA-S400ET in any case.

Yes, as a mastering grade sound card/ADC/2 x DAC with extensive internal routing options the HiLo has been a market leader for years. I think it was or is still around $3,500 or $3,000 + Thunderbolt card in my case.

If I didn't need the AD and dual DAC and routing options I'd get a Topping D90SE or an RME ADI-2 DAC FS, but the latter is missing an AES/EBU XLR input.
The new ADI-2/4 Pro may fit your needs. It has AES-EBU XLR I/O via its breakout cable, top AD conversion, AutoRef volume control for maximum SINAD over wide range, etc.

 
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