Audiophonics HPA-S400ET Review (Stereo Amplifier)

[usa_satriani]

Hello,

Do you think bypass low gain mode can be a problem for impedance matching with a rme fireface (from manual 60 or 30 ohm) and cause bandwidth limit?
I will use it to drive compression drivers so low gain low power low noise is the goal but of course optimum performance.

Regards Greg.

What is output impedance of device used for the test ?

 

[mocenigo]

Hello,

Do you think bypass low gain mode can be a problem for impedance matching with a rme fireface (from manual 60 or 30 ohm) and cause bandwidth limit?
I will use it to drive compression drivers so low gain low power low noise is the goal but of course optimum performance.

Regards Greg.

What is output impedance of device used for the test ?

30 to 60 ohm into 2.5 to 5Kohm is absolutely fine.

 

[usa_satriani]

Thanks.
It is true that the 30 ohm unbalanced TRS output is also an headphone output which drives my Neumann ndh30 pretty well. So why not the amp.

Regards Greg

 

[BR52]

I drive the purfiy in bypass mode with a
100 Ohms output impedance DAC absolutely perfect.

 

[Chester]

I didn’t even think to check but I’ve driven it in bypass with a Chord TT2 and an RME ADI-Pro 2 and it sounded very good. I wasn’t listening for anything specific though.

 

[usa_satriani]

I think I will order LPA-S400ET this week.
I think it is the same procedure to change the gain and set to bypass mode.
Should be great with compression drivers, It is supposed to be quitter and more revelling than my parasound a23...

 

[Overseas]

Who wants a 'quitter' amp!?

 

[usa_satriani]

I mean no ground noise

 

[BR52]

I think I will order LPA-S400ET this week.
I think it is the same procedure to change the gain and set to bypass mode.
Should be great with compression drivers, It is supposed to be quitter and more revelling than my parasound a23...

I drive my horn speakers with it, no noise they’re dead quiet with no signal and amplifier on.

 

[usa_satriani]

I got this response from Purifi

Hello Gregory



With a 75ohm output impedance you can drive the eval1 in bypass mode with no problem.

You can also consider to add series resistors to you compression driver, so you current drive your speakers – often this lowers the motor distortions.

We have several customers that have done this with good effect.

I got the same kind of reply from audiophonics and ordered LPA-S400ET.

Looking forward to hearing it !

It is great to have access to this kind of equipment these days !

 

[usa_satriani]

LPA-S400ET received from audiophonics, bypass mode selected as asked.

I use rew to calibrate gain and replace existing parasound a23. My calculations were correct, I just needed 2db adjustment.
Highs audiophonics lpa-s400et with faital hf108r.(gain 16db)
Mids audiophonics MPA-S125NC on PHL 16cm plus JBL midhorn (gain 26db-6db)
Lows BMS 15s330 on mc2 t1000
Filters dac preamp, rme fireface with asio.

The purifi has very little ground noise on the compression drivers, it is ultra transparent and you can't tell which class of amplification it is. Sweep measurements with rew are the same in terms of frequency response.

The advantage is the low gain low noise low heat compared to the parasound.

It is like having a mojo2 driving compression drivers, it is breathtaking.

 

[cmarion]

Thank you to everyone who contributes to the site! If possible, could someone please explain how superior a pair of Revel M106s would sound powered by the Audiophonics S250 compared to the HPA-S400ET? Also would the 250 be able to power the pair properly with the added load of say a Rythmik subwoofer?

 

[usa_satriani]

The s250 is on paper not as good as hpa and hpa is definitely more powerful.
The lpa is now insanely cheap at 1150€.
What is good is that you can choose what type of buffer you want to use.
Why don't you use an active subwoofer?
The s250 must be powerful enough to run the bookshelves but the purifi is supposed to go further in terms of definition and stereo image.

 

[YSDR]

Highs audiophonics lpa-s400et with faital hf108r.(gain 16db)

Just out of curiosity, what horn/waveguide you use for the highs?

 

[cmarion]

The s250 is on paper not as good as hpa and hpa is definitely more powerful.
The lpa is now insanely cheap at 1150€.
What is good is that you can choose what type of buffer you want to use.
Why don't you use an active subwoofer?
The s250 must be powerful enough to run the bookshelves but the purifi is supposed to go further in terms of definition and stereo image.

Thank you! If I did go with the S400, is there a buffer you would recommend? Also, how would I connect an active subwoofer? Do you take the signal from the amp/buffer directly to the subwoofer, then from the subwoofer to the Revels?

 

[usa_satriani]

Just out of curiosity, what horn/waveguide you use for the highs?

Faital hf108r and faital sth100 horn.
Fantastic, zero harshness yet dynamics and micro details.

Test Bench: Faital Pro HF108R Compression Driver

A Test Bench characterization of the HF108R compression driver, coupled with a LTH102 60° × 50° horn, from Faital Pro.

audioxpress.com

 

[usa_satriani]

Thank you! If I did go with the S400, is there a buffer you would recommend? Also, how would I connect an active subwoofer? Do you take the signal from the amp/buffer directly to the subwoofer, then from the subwoofer to the Revels?

The buffer depends on the gain and taste you need. I went with bypass because I run directly compression drivers. This is a great option for my usage.
Adding a subwoofer means adding a filter and a time alignment and this is a very simple and very complicated question.
Do you have a dac already? A subwoofer already?
Simplest way would be to split the line signal between s400 and active subwoofer. I worry going from the subwoofer to the power amp would not send the best signal to the main speakers.
Best way would be to implement fir filters and delay in a box like mini DSP/ pro sound card...

Svs sb2000, 3000 Can be a nice thing to look at.

 

[cmarion]

The buffer depends on the gain and taste you need. I went with bypass because I run directly compression drivers. This is a great option for my usage.
Adding a subwoofer means adding a filter and a time alignment and this is a very simple and very complicated question.
Do you have a dac already? A subwoofer already?
Simplest way would be to split the line signal between s400 and active subwoofer. I worry going from the subwoofer to the power amp would not send the best signal to the main speakers.
Best way would be to implement fir filters and delay in a box like mini DSP/ pro sound card...

Svs sb2000, 3000 Can be a nice thing to look at.

I have a dac, preamp, and the main speakers. I’m still deciding on the amp. Also trying to decide on whether I should buy a subwoofer. The revels have a non-compression tweeter.

You’re suggesting that the subwoofer built in frequency crossing hardware would be inferior to dedicated crossing equipment from another party? That is what worries me. I’m hoping to find a music amp that outputs for mains and a sub (2.1 or 2.2) and includes frequency crossover capability that would not degrade the signal. Would simplify things.

Those svs subs are a great recommendation. I would likely end up going with one of them.

 

[usa_satriani]

The thing is that if you implement a subwoofer properly with the right crossover for the subs AND for the speakers you would have better bass and better mids as the main speakers would be clear of the low frequencies which will result in less excursion, less distortion and better low mids and mids...
Now the question is how to achieve that.
I don't know if the subwoofer mentioned here from svs filters the response for the mains speakers.
A basic DSP would do the trick.
Or you can look at a basic crown CTS or Yamaha pro amp. They offer a built in DSP.
I think you would have better results if you bought a basic mini DSP and a audiophonics ncore at 400-500€.
I am quite sure the one I have performs better than a parasound a23 it replaced.
That gives you money for the DSP.
With that you can perfectly filter and align the sub and the speakers with sharp filters.

 

[cmarion]

Thank you! To clarify, you’re recommending a mono amp powering a passive subwoofer? That’s a great idea considering the sub amp could be manufactured by the same company powering the main speakers.

As for the dsp, I understand its purpose. However, my dac and preamp only support stereo signals. I’m having trouble understanding how I could digitally separate frequency bands without using a second dac and second preamp for the sub.