AUDIOPHONICS LPA-S400ET Class D Stereo Amplifier Purifi 2x400W 4 Ohm

Two PURIFI 1ET400A modules

Each channel of the amplifier circuit uses its own PURIFI 1ET400A module. These high-performance Class D amplifier circuits each offer a very comfortable 200W at 8 Ohm while benefiting from the high efficiency of Class D amplifiers.

The 1ET400A modules embody a high gain loop greater than 75dB over the entire frequency band, providing high performance over the entire spectrum, surpassing any amplifier of any class.

Highly efficient in terms of Intermodulation Distortion Mode (IMD), these modules enable the LPA-S400ET to deliver a stereophonic image with high accuracy across the entire spectrum, providing even greater clarity during even the most complex musical works.

Harmonic distortion (THD) is kept extremely low at all power levels. This results in a lack of sound signature and the ability to reproduce all types of music without coloration.

The output noise is negligible, which allows deep silences and promotes the appearance of detail when listening at low volume levels.

The circuit benefits from a high rejection level (PSRR) that minimizes the impact of the power supply on audio performance.

The load-independent frequency response makes it possible to enjoy all the qualities of this amplification technology, even with the most difficult to drive speakers.

Low power consumption at rest and electromagnetic radiation (EMI). The high gain loop significantly relieves the workload of MOSFETs and allows them to operate under optimal operating conditions, reducing losses and EMI emissions.

The LPA-S400ET has its amplifier modules connected with a specially developed interface card for optimal integration.

Hypex Power Supply Module SMPS1200A400

The SMPS1200 switched-mode power supply is a very high efficiency model capable of developing a rated power of 1200 Watts in an extremely small footprint. It has been specifically designed and developed by Hypex to provide the 2x64V voltage required to operate the most demanding amplifier modules.

This low-noise quality power supply meets the power requirements of the amplifier modules in every respect. In addition, the amplifier modules themselves have an excellent ability to reject supply noise. This makes the LPA-S400ET extremely insensitive to mains imperfections and voltage/current fluctuations that can cause interference noise.

Audiophonics interface board

The 2 modules are driven in phase opposition, to cancel the "Power-Supply Pumping" effect. This allows a greater stability of the power supply, distributing alternately on each rail the calls of current and thus increasing its capacities.

We have opted for a 2-level voltage regulation, to optimise the power supply to the OPAs and the auxiliary voltage supplied to the modules.

One Texas Instrument LM4562 OPA per channel is used. These are very low distortion OPAs offering the highest transparency with a very low THD. They are mounted on a DIP8 socket, allowing their replacement if needed.

Gain of +7.2dB, i.e. a total of 20dB (default) - Maximum power reached with a signal of -4.2V RMS.

Gain of +12.5dB, i.e. a total of 25.3dB - Maximum power reached with a signal of -2.25V RMS.

Bypass: In this case, the signal passes directly from the inputs to the modules, allowing the lowest possible gain of 12.8dB. This mode can be interesting when using a strong preamplifier, capable of driving a 2 to 4K Ohm load and reaching a voltage of -10V RMS.

Connectivity

Designed for easy integration, the LPA-S400ET has a balanced (XLR) and unbalanced (RCA) stereo input. Bipolar switches allow easy switching between input sources and even allow independent channel control.

On the output side, BP-207 carbon / 24k Ø5.5mm gold / carbon insulated terminals provide an excellent connection to the loudspeakers.

Specifications
Product type	Power amplifier
Power	227W @ 8Ω, 1%THD 425W @ 4Ω, 1%THD 450W @ 2Ω, 1%THD
THD+N	0.0007% @ PO=1W, f=1kHz 0.00026% @ PO=10W, f=1kHz 0.00015% @ PO=100W, f=1kHz 0.0007% @ PO=1W, f=20Hz-20kHz 0.00029% @ PO=10W, f=20Hz-20kHz 0.00017% @ PO=100W, f=20Hz-20kHz
IMD (CCIF)	0.00025% @ PO=1W, f=18kHz+19kHz 0.00022% @ PO=10W, f=18kHz+19kHz 0.00027% @ PO=100W, f=18kHz+19kHz
IMD (DIM)	0.002% @ PO=1W, DIM30 0.002% @ PO=10W, DIM30 0.002% @ PO=100W, DIM30
Quiescent noise	11.5µV (A-Weighted)
Dynamic range	131dB @ 4Ω (A-Weighted)
SNR	131dB @ 4Ω (A-Weighted)
Frequency response	20Hz - 20kHz ±0.01dB @ RL=8Ω 20Hz - 20kHz ±0.01dB @ RL=4Ω 20Hz - 20kHz ±0.01dB @ RL=2Ω
Output impedance	Iout = 1A @ 0.07mΩ, 1kHz Iout = 1A @ < 0.65mΩ, 20Hz-20kHz
Input impedance	RCA : 47kΩ / XLR : 100kΩ Bypass : 2.2kΩ / 4.4kΩ

Specifications

Product type

Power amplifier

Power

227W @ 8Ω, 1%THD
425W @ 4Ω, 1%THD
450W @ 2Ω, 1%THD

THD+N

0.0007% @ PO=1W, f=1kHz
0.00026% @ PO=10W, f=1kHz
0.00015% @ PO=100W, f=1kHz
0.0007% @ PO=1W, f=20Hz-20kHz
0.00029% @ PO=10W, f=20Hz-20kHz
0.00017% @ PO=100W, f=20Hz-20kHz

IMD (CCIF)

0.00025% @ PO=1W, f=18kHz+19kHz
0.00022% @ PO=10W, f=18kHz+19kHz
0.00027% @ PO=100W, f=18kHz+19kHz

IMD (DIM)

0.002% @ PO=1W, DIM30
0.002% @ PO=10W, DIM30
0.002% @ PO=100W, DIM30

Quiescent noise

11.5µV (A-Weighted)

Dynamic range

131dB @ 4Ω (A-Weighted)

SNR

131dB @ 4Ω (A-Weighted)

Frequency response

20Hz - 20kHz ±0.01dB @ RL=8Ω
20Hz - 20kHz ±0.01dB @ RL=4Ω
20Hz - 20kHz ±0.01dB @ RL=2Ω

Output impedance

Iout = 1A @ 0.07mΩ, 1kHz
Iout = 1A @ < 0.65mΩ, 20Hz-20kHz

Input impedance

RCA : 47kΩ / XLR : 100kΩ
Bypass : 2.2kΩ / 4.4kΩ

General
Power supply	230V (110V on demand)
Dimensions (without connectors)	19 x 35.9 x 7.8cm
Weight	3.17kg
Housing material	Aluminium
Color	Black

General

Power supply

230V (110V on demand)

Dimensions (without connectors)

19 x 35.9 x 7.8cm

Weight

3.17kg

Housing material

Aluminium

Color

Black

Input	RCA
Input	XLR
Output	Speaker terminal
Color	Black
Channel	Dual Mono
Light symbol	Yes
Class	Class D / T
Fuse holder	Yes
Amplifier chip	Purifi 1ET400A
Power (W)	400.0

Excellent Performance in Small Box
I have purchased HPA-S400ET to compare with Ncore amps(NC400 and NC250MP both dual mono).
This is one of the best power amplifiers.
- Smaller size than HPA-series box
- Easy to change preferable gain
- Easy to change interface OP amps
I have checked with
(a) default ( 20dB Gain and OP amp = LM4562NA)
At first it came to us, it sounded somewhat shiny than NC400.And details was decreasing from Ncore400.
After burn-in several hours, it changed to smoother and little shiny, to better normal hi-end quality.
It may require some burn-in hours for (maybe) large power supply(SMPS1200A400).

(b) OP amp JRC MUSES 8920 and setup gain 25.3dB
After burn-in I have tried to change gain and OP amps.

I was very surprized at upgraded sound when I changed to 25.3dB and MUSES8920.
I strongly recomend to try to change OP amps and change gain to fit to your audio system characteristics.
You will find the best matching combination with gain and OP amps.

With Size , sound characteristics and adjustable functions (gain and OP amps) , I am very satisfied with LPA-S400ET.

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Surprenant !!
Je me décide à changer de configuration et après plus de 15 ans de bons et loyaux services je remplace mon ampli Linn AV5125... choix très difficile de remplacement, il était épaulé par un dac Naim V1, j'ai opté pour un Nad Master m32, mais sans vouloir exploiter la partie amplification car en deça de mes attentes. sur les conseils avisés d'Audiophonics je me suis tourné vers cet ampli, septique, très septique même, mon premier choix s'était orienté vers de l'AudioGD, mais j'ai suivi ce précieux conseil. j'ai demandé à ce que soient installés les AOP sparkos, et que l'ampli soit réglé en config 2... 3 jours après ma commande, la réception ! J'ai lu dans d'autres commentaires que l'emballage était sommaire et je m'attendais donc à recevoir un ampli avec un emballage sommaire il n'en n'a rien été car l'ampli est parfaitement emballé je dirais même doublement emballé est parfaitement protégé j'apprécie toujours les envoie soignés et je ne suis pas déçu... Place à l'installation... et première écoute.... Mon angoisse monte, le son est étouffé, pas de spacialisation...je me dit attendons le rodage sans trop écouter pour ne pas s'habituer à un son de m...après deux jours durant lesquels il a tourné en moyenne 10h, là ce n'est pas une claque mais un hypercut !!! je trouvais mon association Linn/naim excellente et aujourd'hui j'en viens à me dire que j'avais une écoute basique... aujourd'hui tout est défini parfaitement en place, mes enceintes, des Tannoy dc8t, exprimant tout leur potentiel dînas les aigus, les graves sont détaillés, précis non baveux et d'une pureté déconcertante... je suis stupéfait de la qualité d'écoute. mes câbles de liaisons et d'alimentation sont les même qu'avant... Merci Audiophonics pour cette réalisation !!

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Ampli voie grave
Ampli reçu en 48h très bien emballé comme d'habitude avec Audiophonics.

Il est installé sur la voie grave de mon système 3 voies avec filtre actif, branché en XLR. Il drive deux 38 cm Supravox en charge Jenssen et remplace un Micromega PW400.

J'ai rapidement changé l'AOP par un Sparkos Labs et paramétré l'ampli en configuration 2 (Gain +) via des jumpers commandés en plus. L'ouverture est simple et l'intérieur montre un ampli bien construit et a priori robuste. Le format "slim" est particulièrement agréable.

A l'écoute, après avoir ajusté le niveau des voies, le son est puissant, rapide, clair et "dégraissé". Les textures me paraissent plus naturelles et les attaques plus percutantes. J'ai redécouvert les lignes de basse des mes pistes favorites.

Je pense remplacé l'ampli de la voie aigue par le même modèle avec les mêmes compléments.

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a Game changer
I've been a fan of Bruno Putyz and his designs for many years and consider him a pioneer of Class D. Hypex, N-core have been adopted by so many high end manufacturers NAD, Bel Canto etc etc. I was very excited when Purifi announced eigentakt. Even more so when audiophonics packaged it so attractively and affordably for the enthusiast with the well proven Hypex SMPS power supply. An immediate buy. I love building but dont have the machinery or time for nice casework.
Comments. Excellent build quality in and out. If you want pretty spend another 5k.
initially disappointed with sound compared to Nord n core monblocks with hardy discrete amps.
Immediately looked at lm4652 (see other reviews) and replaced with sparkos discrete dual opamps. A revelation. up there with the very best. This is super audiophile at bargain basement prices.
Tres bien. Merci beaucoup.
NM

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AUDIOPHONICS LPA-S400ET
I split my review into three chapter, 1, product and service, 2, sound quality, 3 power rating
1, I have ordered the amp. on a weekend, received the following Friday. At other sources you should calculate minimum 2-4 weeks lead times! So, the speed of delivery was absolute fantastic! Well done! Thank you! Everybody mentioning of the packaging, because there is no special hard paper box, but we get double box with filling material, which is safe enough. The product itself is very solid, nicely built and looks even better in reality than on pictures. Well done! Thanks a lot!
2, I had to wait with this review a week, because I had to find the right cabling. I made the change for this amp from an Emotiva XPA Gen2. When I simple changed them and used the same cables I have got quite week sound. So I started the big changing /fine tuning/ process. Making the long story short, I have changed each cable, selected them out from many alternatives, creating a formerly not used combo from the power cord trough out the USB cable, the RCA digital signal cable, the XLR analog cable and finally the speaker cable. By this process I finally arrived to a very capable, decent, detailed, extreme clean sound which I did not hear from my system so far. Thanks a lot for this!
3, Regarding the power level. The Emotiva papered 500 wpc at 4 ohms. The Purifi rated 425 wpc at 4 ohms. In real life that should not be felt so differently. But if I want to reach the same feeling of sound pressure with the Purifi like with the Emotiva, I need to turn up the DAC/Preamp volume controller from 50% to 75% and at the same time the Windows volume controller from 40% to 50%. ( the Tidal volume controller than can stand on the same place) . So according to my subjective feeling the wpc different is rather around 150 watt instead of 75 watt, which can mean that either the Emotiva delivers more or the Purifi less. ( or both at the same time )
Anyhow, this amplifier absolutely worth the money! Well done, thanks again!

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