The next remarkable thing is the output diode packs. A majority of PSUs employ packs like Mospec S30D40C in large TO-247 cases. This model uses Fairchild YM3045N (MBRP3045N ) diode packs in TO-220 cases, but there are as many as twelve packs here, six on each side of the heatsink:

At first, before checking the marking, I thought the engineers used a synchronous rectifier. For people who are not well versed in electronics, a synchronous rectifier is a circuit in which MOSFETs replace diodes and are controlled in such a way that one transistor opens on arrival of a positive half-wave and the other opens on the arrival of a negative one. Thus, the transistors imitate the operation of ordinary diodes but feature a higher efficiency – the voltage drop on a diode is constant (about 0.7V for a silicon diode and about 0.5V for a Schottky diode), while the voltage drop on a transistor depends on its type. So, transistors with a minimal resistance in the open state make it possible to reduce the voltage drop considerably and, accordingly, to increase the rectifier’s efficiency.

The Zen, however, uses ordinary diode packs (each rated for an up to 30amp current, 45V voltage and 150°C temperature of the die) which are connected in parallel in twos to ensure the required load currents at high temperatures.

And the last interesting feature of this PSU model is the abundance of toroid-core throttles on the output which are a sign of independent regulation of the output voltages. As I wrote in my previous reviews, in the classic PSU design the +3.3V voltage has a dedicated auxiliary regulator on a magnetic amplifier (of which a choke coil is the main component), but the +5V and +12V voltages are regulated together with a so-called group-regulation choke. This solution helps to make the power supply cheaper and simpler, but the result isn’t quite perfect. For example, if there’s a high load on the +5V rail and this voltage “bottoms out”, the +12V voltage grows up above the norm as a consequence of the group regulation. In power supplies with dedicated voltage regulation the main regulator is only watching over the +12V rail, while the +5V is served with an auxiliary regulator like the one installed on the +3.3V rail. As a result, the +12V and +5V voltages of the PSU become in fact independent of each other. You can tell such a PSU visually by noticing not two but three large choke coils on the output (by the way, there can even be only one – group regulation – choke in some cheap power supplies).

The power supply offers the following cables and connectors:

• A 38cm cable with a 20+4-pin mainboard’s connector (the 4-pin part can be detached from the main section of the connector)
  
  
  
• A 38cm ATX12V cable with a 4-pin connector
• Two cables with Molex connectors (38cm from the PSU to the first connector and 14cm more to the second one). These connectors have two “lobes” on the sides for easy unplugging
  
  
  
• A cable with two Molex connectors and one floppy mini-plug (38cm+14cm+14cm)
• A cable with two SATA power connectors (39cm+14cm)