Hifistatement: The HYPSOS combines the technology of a switched-mode power supply with that of a linear power supply. How do these two types work together in HYPSOS and what are the advantages of a hybrid power supply unit?
Max: We decided on a hybrid design for the HYPSOS because we wanted to keep the residual ripple and noise at the output low, but still wanted to have a large output voltage range. A linear regulator is the best to keep the noise down, but with the HYPSOS output voltage range the heat sink would be the size of the moon so we had to find another way. That's why we decided to keep the linear regulator but put an efficient stage with a switching regulator in front of our discrete low-drop-out voltage regulator (LDO), which keeps the voltage at the LDO constant and minimizes power dissipation. This allowed us to keep the power loss low, but the residual ripple at the output is greatly reduced because we are still using a linear regulator. As I said, it suppresses the residual ripple. Besides, we use a two-stage LC filter after the switching converter to further suppress the noise to smooth the voltage at the output of the regulator. All in all, we have succeeded in developing a power supply unit that has a lower power loss than a linear regulator. But we still have a fast transient response in switching current, low noise, and low ripple, as is the case with the linear regulator. This wouldn't be possible if we were just using a switching regulator.

Hifistatement: 4T Sensing Design and Spread Spectrum Mode are two special functions of the power supply. Please briefly explain to our readers how they work and tthe resulting effect on audio reproduction.
Max: 4 Terminal Sensing Design (4TSD) is a feature that greatly reduces the influence of the cable resistance on the voltage at the output of the cable. Most external power supplies measure their output voltage directly at their output, but not at the load, at the end of the cable. Therefore, the current supplied by the power supply is what causes the voltage drop across resistance of the cable. So, if the current supplied by the power supply is high, the voltage seen by the load may be lower than the voltage at the output of the power supply. For this reason, the HYPSOS is equipped with 4TSD, which measures the voltage directly at the output of the cable and not at the output of the power supply, so that the effect of the voltage drop on the cable is minimized. We use a 4-wire cable, with two wires for the power supply and the other two wires for voltage measurement. In this way, the high current only flows through the two wires that are intended for the power supply. Almost no current flows in the cores that are intended for voltage measurement so that there is no voltage drop in these measuring cables and the influence of the cable resistance is reduced to a minimum. This is very important as changing the supply current has much less impact on the output voltage and causes much less distortion when the 4TSD is activated. The spread spectrum mode is a possibility to reduce the high-frequency emission caused by the switching regulator. It modulates the switching frequency of the controller, which lowers the level of the main switching frequency ripple and its harmonics. As a result, there is less noise from the power supply that some amplifiers might modulate back into the audible range.