We are proud to present AUDIOPHONICS HPA-S400ET, a class D stereo power amplifier based on two PURIFI 1ET400A modules. This ready-to-use version is designed for audiophiles needing a foolproof amplification solution, with a considerable power reserve as well as impeccable linearity. The PURIFI modules are indeed among the most rigorous Class D amplification solutions on the market, with simply exceptional measured performance.

This device offers high level sound reproduction which will be suitable to drive demanding speakers, to sonorize large listening rooms or for studio applications requiring a considerable headroom without compromising on the precision and richness of the audio message.

All of the components are integrated in a sober and robust 100% Aluminum housing with openings and heatsinks to help heat dissipation. Its design also allows it to block signal interference.

• The output noise is negligible, which allows deep silences and prevents losing details when listening at low volume.
• The circuit benefits from a high level of rejection (PSRR) which minimizes the impact of power supply on audio performance.
• Load-invariant frequency response and negligible output impedance enables the HPA-S400ET to drive the most demanding speakers with ease.
• Very low idle losses and reduced electromagnetic interference (EMI). The High loop gain allows relaxed timing of the power MOSFETs without degrading audio performance.
• The HPA-S400ET uses these amplifier modules with an interface card specially developed for optimal integration.

Audiophonics Interface Card

Both modules are driven in opposite phase, to cancel out the «Power-Supply Pumping» effect. This allows greater stability in the power supply by alternately distributing current draws on each rail, thus increasing its overall capacities.

We opted for a two stage voltage regulation in order to optimize the power supply to the OPAs and the auxiliary voltage supplied to the modules. 

A Texas Instrument LM4562 OPA per channel is used, these are very low distortion AOPs offering the greatest transparency with a very low THD. They are mounted on socket allowing their replacement if necessary

To suit all uses we opted for 3 gain settings, adjustable by jumper on the interface board.

Connectivity

Designed for easy integration, the HPA-S400ET has a balanced stereo (XLR) and unbalanced (RCA) input. Bipolar selectors make it easy to change the input source and even allow independent channel control.

On output side, BP-207 Carbon / Gold 24K Ø5.5mm speaker terminals ensure excellent connection with the speakers.

A trigger module allows the amplifier to be switched on automatically from a distance. This is compatible with voltages from 5 to 12V.

THD+N

Frequency response

THD vs Freq

Test du Audiophonics HPA-S400ET par Audio Science Review (Amir)

" The Audiophonics HPA-S400ET comes in a beautiful package with super performance to match its good looks. Yes, it builds on Purifi's excellent platform but they managed to add value without messing with its performance. The gain settings are well thought through. The whole thing is so well executed and must be a delight to our European members who can buy it locally. Having been built in France, it is also a feather in the cap of our French members. I am happy to give my strongest recommendation to Audiophonics HPA-S400ET. You have a lot of power with superb fidelity and transparency. "