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Audiophonics HPA-S400ET Review (Stereo Amplifier)

Rate this amplifier:

  • 1. Poor (headless panther)

    Votes: 0 0.0%
  • 2. Not terrible (postman panther)

    Votes: 3 0.8%
  • 3. Fine (happy panther)

    Votes: 29 7.5%
  • 4. Great (golfing panther)

    Votes: 353 91.7%

  • Total voters
    385

Dlomb11

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I also quote Purifi's very kind reply:

The online 1ET400 datasheet describes the supply pumping effect that exist with single ended class-d amplifiers like the 1ET400. See section 4.1.1.


Some power supplies have active rectifiers and do not have issues with supply pumping, like the HYPEX SMPS1200A400, where as the SMPS3KA400 can have issues.
We use the SMPS1200A400 in our demo amp, and do not invert the phase on one channel.

With other power supplies that do not have active rectifiers the phase inversion is highly recommended.
 

Rottmannash

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index.php

And the 252MP

index.php

Now look at 8 ohm.
index.php


This amp:

index.php

At 4 ohms they appear similar in power but not sure of the distortion on the 252MP amp. Into 8 ohms the Purifi produces 144 vs 105 watts. They are similar but I believe the incredibly low distortion numbers for the Purifi are the real difference when considering these amps. I have one of each and they are similar but the Purifi drives my F208's with more authority at high volumes than the 252 MP.
 

PeteL

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index.php

And the 252MP

index.php

Now look at 8 ohm.
index.php


This amp:

index.php

At 4 ohms they appear similar in power but not sure of the distortion on the 252MP amp. Into 8 ohms the Purifi produces 144 vs 105 watts. They are similar but I believe the incredibly low distortion numbers for the Purifi are the real difference when considering these amps. I have one of each and they are similar but the Purifi drives my F208's with more authority at high volumes than the 252 MP.
I hear you, the Ion that I linked develop a bit more than the Buckeye, for reasons that I ignore because these modules each have their own power supply, even tough there is multi channels here. That said I have no doubt that Purifi is better, has less distortion and yes in the end, even in the clipping zone in effect, it will stay cleaner for higher volumes even with some transient clipping, more distortion is more distortion, wheter it's due to overload or not. But I think you get my point tough. ET400A, despite it's "name" is more of a 250W amp module that has been so optimized that you can clip it and still have audibly clean signal for a good few dBs more margin. That's what it really mean, The NCore 500 give more power.
 

Rottmannash

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I hear you, the Ion that I linked develop a bit more than the Buckeye, for reasons that I ignore because these modules each have their own power supply, even tough there is multi channels here. That said I have no doubt that Purifi is better, has less distortion and yes in the end, even in the clipping zone in effect, it will stay cleaner for higher volumes even with some transient clipping, more distortion is more distortion, wheter it's due to overload or not. But I think you get my point tough. ET400A, despite it's "name" is more of a 250W amp module that has been so optimized that you can clip it and still have audibly clean signal for a good few dBs more margin. That's what it really mean, The NCore 500 give more power.
Agreed.
 

theREALdotnet

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The 1ET400A module, as used in this Audiophonic amp, has differential inputs, with no reference to ground. So does the 1Eval buffer board. You can simply swap the + and - leads on the input and undo the change by swapping the speaker terminals, if that’s what you want to try.

If you use a different buffer board that has RCA inputs you would need to know how that is implemented, before trying the same.
 

Waxx

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Most audiophonics products are well build, even the boards they sell seperatly. So i'm not surprised they did this amp well and it ends up in the topsection of your ranking.

But Purifi is class D so not my favorites in general, but it's that good that even for a non-fan of class d amps it's still enjoyable. For monitoring purpose it's not even questioned, it's the best. But for enjoying music i prefer a bit more harmonic distortion...
 

Vincentponcet

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Most audiophonics products are well build, even the boards they sell seperatly. So i'm not surprised they did this amp well and it ends up in the topsection of your ranking.

But Purifi is class D so not my favorites in general, but it's that good that even for a non-fan of class d amps it's still enjoyable. For monitoring purpose it's not even questioned, it's the best. But for enjoying music i prefer a bit more harmonic distortion...
Use a VST plugin with a tube emulation
Or that purifi with a tube input buffer.
 

timtt

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Has anyone brought anything from Audiophonics (in Canada)? How much is total cost? Price+shipping+tax?
 
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bobitto

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Has anyone brought anything from Audiophonics (in Canada)? How much is total cost? Price+shipping+tax?
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.
 

Mehdiem

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I am contemplating returning my newly purchased NAD C298 (due to an auto-shutoff defect). Currently, I have two alternatives in mind (Audiophonic and VTV). I’m from Canada, and I purchased the C298 for about $1,850 USD (before tax).

I am not concerned about the price difference between these alternatives, but rather care more about the quality and reliability of the amp. A good residual value would be a bonus. Which amp do you recommend? Or should I keep my NAD (and exchange it to get it fixed?).

If you recommend VTV, what input buffer would you recommend and how does it compare to NAD and Audiophonics?

I understand that the gain control in Audiophonic is not accessible from outside. What is the benefit of having gain control? My pre-amp is RME ADI2
 

amper42

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I am contemplating returning my newly purchased NAD C298 (due to an auto-shutoff defect). Currently, I have two alternatives in mind (Audiophonic and VTV). I’m from Canada, and I purchased the C298 for about $1,850 USD (before tax).

I am not concerned about the price difference between these alternatives, but rather care more about the quality and reliability of the amp. A good residual value would be a bonus. Which amp do you recommend? Or should I keep my NAD (and exchange it to get it fixed?).

If you recommend VTV, what input buffer would you recommend and how does it compare to NAD and Audiophonics?

I understand that the gain control in Audiophonic is not accessible from outside. What is the benefit of having gain control? My pre-amp is RME ADI2

You set the gain and forget it. No need to be switchable. I would get the Audiophonics or the Buckeye Purifi. As far as I'm concerned the NAD has too much crap on it. I would also recommend the March Audio P452 but it's more expensive ($1700) and I don't see any real value in paying more. Personally, I would stay away from VTV as I believe the build quality isn't as nice as Audiophonics or Buckeye. When you buy a Purifi amp the modules are pre assembled and the power supply is specified with the Eigentakt design. Once the builder starts adding a different power supply and various opamps it deviates from the original design and can easily measure worse. If you can get the Audiophonics HPA-S400ET, it would be a great option.
 
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ENG

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I bought NAD C 298 recently. There's no problem with auto shot/off at all. And subjectively the sound is very clean. I admit that NAD do produces items with very different quality.
 

KMO

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When you buy a Purifi design the modules are pre assembled and the power supply is specified with it.
Just to nit-pick, Purifi don't specify any particular power supply, just the requirements. And the Hypex supplies usually used aren't a perfect fit - they're a bit lower voltage than ideal for the 1ET400A (63V rather than 65V), so there is scope for improvement on power supply at least, giving a tad more headroom. And Hypex supplies are even less of a good fit for the nearly-here 1ET7040SA. But yes, there's plenty of scope to screw up by doing something unconventional in power supplies or buffer boards too.

I believe NAD have fitted power supplies and heatsinking rendering their Purifi designs capable of longer-sustained peak power operation than some of the other vendors, but that's not going to be a real-world gain for most.
 

daniboun

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Nice review, thanks Amir )

The HPA-S400ET seems to perform a bit better than the EVAL1 Purifi.
The buffers come with some LM4562 op amps.(DIP8 socket)

Amir, it wouldn't hurt to test with other op amps: OPA1656, OPA2210 and 1612 for example. Just to let us know if the op-amps affect the measurements slightly ? thanks.
 

KMO

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Amir, it wouldn't hurt to test with other op amps: OPA1656, OPA2210 and 1612 for example. Just to let us know if the op-amps affect the measurements slightly ? thanks.
A lot of the tests were shown with the op-amps and buffers totally bypassed, which strikes me as unhelpful - they're going to be one of the main potential sources of difference between Purifi implementations, and most people will be using them, so for the tests to be useful for comparisons, you want to keep them in-circuit throughout. Otherwise you're just re-testing the bare Purifi modules, almost. (But I guess you learn a bit about the wiring.)
 

daniboun

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A lot of the tests were shown with the op-amps and buffers totally bypassed, which strikes me as unhelpful - they're going to be one of the main potential sources of difference between Purifi implementations, and most people will be using them, so for the tests to be useful for comparisons, you want to keep them in-circuit throughout. Otherwise you're just re-testing the bare Purifi modules, almost. (But I guess you learn a bit about the wiring.)


I'm not saying the opposite but it wouldn't take much to confirm it via a simple test, especially since they are DIP8 and therefore very easy to update. This would confirm or disprove the myth of OP amps.
Besides, I think it's no coincidence that Neurochrome uses these same LM4562 in their Purifi Buffer...
 

KMO

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Amir did test one amp with two different discrete op-amps:

VTV Purifi Amplifier With SIL 994EnH-Ticha Pro Buffer Review
VTV Purifi Amplifier Review with Weiss Buffer

Both performed worse than the OPA1612-based reference, but can't necessarily pin it on the op-amps themselves.

Oh, and another:

Discrete OpAmp Review: Sonic Imagery vs Sparkos

Don't think IC opamps have been compared though.

A bit of Googling suggests that the OPA1612 from the reference is marginally higher-spec than the LM4562, but significantly more expensive. But they're both very highly rated. (Lots of people saying the OPA1612 is not worth the extra price, cos the LM4562 is already very good)
 

daniboun

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Amir did test one amp with two different discrete op-amps:

VTV Purifi Amplifier With SIL 994EnH-Ticha Pro Buffer Review
VTV Purifi Amplifier Review with Weiss Buffer

Both performed worse than the OPA1612-based reference, but can't necessarily pin it on the op-amps themselves.

Oh, and another:

Discrete OpAmp Review: Sonic Imagery vs Sparkos

Don't think IC opamps have been compared though.

A bit of Googling suggests that the OPA1612 from the reference is marginally higher-spec than the LM4562, but significantly more expensive. But they're both very highly rated. (Lots of people saying the OPA1612 is not worth the extra price, cos the LM4562 is already very good)

Hence my reaction) the OPA1612 on paper is better than the LM4562 but in fact, the HPA-S400ET / LM4562 does better than the EVAL1 / OPA1612... so an OP amps test to help us dispel any doubts!

Jlester demonstrated that on his Sylph-D200 module, the OP amps had a definite influence on the measurements(I imagine it is also applicable for the Purifi) ... That's why he offers two different OP amps for sale...

I prefer a good test from Amir rather than speculation) Amir, can you give us your verdict since you have the components in stock)
 
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