We are proud to offer you the Audiophonics LPA-S400ET, a Class D stereo power amplifier based on two Purifi 1ET400A modules. Similar electronically to the HPA-S400ET, this version is mounted in a more compact box making it easier to use in an environment where space is limited, its architecture also limits the length of the internal connections.

This ready-built and ready-to-use version is for audiophiles who want to equip themselves with a foolproof amplification solution, with a considerable power reserve as well as a perfect definition. PURIFI modules are among the most rigorous Class D amplification solutions on the market, with simply outstanding measured performance.

The package offers a high level of sound reproduction suitable for use with demanding loudspeakers, for large listening rooms or for studio applications requiring a large headroom without compromising on the accuracy and richness of the audio message.

All the components are integrated in a 100% Aluminium housing that is sober, robust, design and compact. This one has openings in order to facilitate heat dissipation. Its design also allows it to limit the impact of interference on the signal.

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 Audiophonics OPA1656 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.

To suit all applications, we have opted for 5 gain settings, switchable via jumper on the underside of the unit :

• Gain of +7.2dB, i.e. a total of 20dB - Maximum power reached with a 4.19V RMS signal.
• Gain of +12.5dB, i.e. a total of 26dB (default) - Maximum power reached with a signal of 2.07V RMS.
• Total gain of 32dB - Maximum power reached with a signal of 1.05Vrms
• Total gain of 34dB - Maximum power reached with a signal of 0.83Vrms
• Bypass (buffer deactivated): In this case, the signal passes directly from the inputs to the modules, allowing the lowest possible gain of 12.5dB. This mode can be interesting when using a powerful preamplifier, capable of driving a load of 2 to 4K Ohm 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.

THD+N

Frequency response

THD vs Freq