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.
Dual PURIFI 1ET400A module
Both channel of the amplification circuit uses its own PURIFI 1ET400A module. These high performance Class D amplifier circuits each offer a very comfortable power of 200W (@ 8Ω) while making the most of Class D amplifiers high efficiency rating.
The 1ET400A modules has a >75dB high gain loop over the entire frequency band, providing high performance across the whole spectrum and surpassing any amplifier regardless of its class.
Thanks to hyper-low intermodulation distorsion (IMD) the HPA-S400ET achieves incredible precision on its stereophonic image over the whole spectrum, unmatched by audio amplifiers of any technology or operating class.
THD remains extremely low at any frequency and any power level right until clipping. This translates into a total lack of sonic signature, and an ability to reproduce any type of music without preference for genre or production style.
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.
Power Module Hypex SMPS1200A400
The SMPS1200 switching power supply is a model with very high maximum output power of 1200 Watts. It has been specifically designed and developed by Hypex to provide 2 x 64V voltage required for operation of the most demanding amplifier modules.
This low noise high quality Power supply, meets every energy needs of the amplification modules.
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 regulation with two voltage levels in order to optimize the power supply to the PDOs and the auxiliary voltage supplied to the modules. This allows the OPAs to be powered with a high voltage (18V) for better overall performance, and allows them in turn to provide the voltage needed to reach the amplifier's maximum output level. While still maintaining the auxiliary voltage required by the modules.
Each channel uses its own Analog Devices OP275 AOP. they are based on a hybrid Bipolar / JFET technology. bringing precision and musicality. They are mounted on a socket allowing their possible replacement.
To suit all uses we opted for 3 gain settings, adjustable by jumper on the interface card:
Gain of + 7.2dB, for a total of 20dB (default) - Maximum power reached with a signal of ~ 4.2V RMS
Gain of + 12.5dB, for a total of 25.3dB - Maximum power reached with a signal of ~ 2.2V 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 powerful preamplifier, capable of driving a load of 2 to 4kOhm and reaching a voltage of ~ 10V RMS
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.
RL= 8Ω, f= 20-20kHz ±0.01 dB RL= 4Ω, f= 20-20kHz ±0.01 dB RL= 2Ω, f= 20-20kHz ±0.01 dB
1kHz, Iout=1A 0.07 mΩ 20-20kHz, Iout=1A <0.65 mΩ
RCA: 47kΩ / XLR: 94kΩ Bypass: 2.2kΩ / 4.4 kΩ
413 x 322 x 60mm
Accepts Banana Plugs
Class D / T
Total Power (W)
Input voltage (V)
We deliver all of France, and internationally. To discover the amount of the shipping costs, you just have to go in your shopping cart once the desired products added. To discover our different services and delivery options, click on the following logos: