Introduction:::...

In a warm, dark corner of your PC sits a mysterious little box of tricks. Underestimated and misunderstood, it provides the very lifeblood that your PC needs to function......power.

Of course if you visit any enthusiast site or forum you'll hear talk about the importance of an ample supply of clean power and just how valuable a high quality PSU is for the stability of your PC, but with even the sub-£30 budget cases boasting 300 watt or bigger units fitted as standard just how can you tell the good from the bad?

In truth that's a pretty tough question to answer. The modern power supply is both a very simple yet and extremely complicated device. The theory behind its operation isn't rocket science, but the way in which it has been tweaked, timed and developed makes accurate testing just about impossible for sites who don't have access to specialist equipment.

But all isn't lost. We may not be able to delve into the psychology of a power supply but that doesn't mean we can't get a feel for its personality. There are some telltale signs that almost always identify a power supply as being a high quality unit and it's those we'll be looking for. And it's not all about the number of Watts on offer either!

Today's candidate is from a company I'm told is quite well known in Europe, though I can't pretend I'd ever had any dealings with them in the UK. Tagan, according to their site, was created by a bunch of guys who were bitching one day that they couldn't find an off-the-shelf power supply that met their high standards. So, to cut a long story short, they starting building some! The result is a German company captained by a team of international personnel who want to rule the world. Okay, I made the last part up, but they do want to rule the power supply world, and are making some bold moves to get there.

On the bench today I have the TG480-U01, a large, black 480 watt unit with some impressive specs and innovative features. Here's the tale of the tape:

If that didn't mean a whole lot to you let's pick through it and see what's important:

Gold Plated Connectors: Hardly an essential feature but a nice one all the same. Gold is an excellent conductor and plating the conductors in gold will help but it's not quite as essential a feature as it would be on an audio connector for example.

Twisted Wires: Not really my field of expertise but I do know that twisting the cables can reduce EMI quite significantly. The tightness of the twists can be pretty critical in how effective this method works so I'll just have to trust that the guys have done their homework. What I can say for certain is that twisted cables do look neater.

Ground Wire: Power supplies very often ground through their casing which screws to the chassis anyway so I'm not certain what the benefits of a separate ground wire are if any. Tagan state it improves stability so unless you can enlighten me otherwise I'll have to assume they're right.

Rubber Switch Protection: This is an interesting one, and one that has me a bit baffled. I don't imagine it's to keep dust out as this would most likely ingress from inside anyway if it's going to. Nor do I envisage too many instances where I'll be operating the switch with wet hands. I guess I'll have to go with the premise that any protection beats none, though I wish I'd remembered that before my first was born!

Black Anodized Heat Sink: Black surfaces radiate and absorb heat better according to Stefan-Boltzmann and thus a black heat sink should be more efficient at cooling the internal components. In actual practice, black is probably only more efficient under low airflow situations which, in the case of a thermally or load controlled fan, will be more often than would normally be the case otherwise. Anodizing is considered more effective than painting as the original surface material is retained and thus the actual surface treatment can't retain heat as an undesirable side effect.

Wide Range Input: Some power supplies require you to throw a selector switch based on the voltage used in your country. Others accept voltages in a couple of ranges, usually around 90 to 130V then 190 to 265V. In the Tagan's case the input voltage can be absolutely any value between 95 and 250 volt and the power supply will operate normally.

Active PFC: Let's keep this one simple. When a power supply consumes power, not all of it is being used productively, some of it is simply wasted. The more efficiently your power supply makes use of the power it draws the higher its efficiency and the lower the waste, and thus the lower your electricity bills.

PFC, or Power Factor Correction, is used to fine tune the timings of the circuit so that working power and total power consumed are as closely matches as possible. In a perfect circuit the PF would be 1.0 (100%). An average power supply with the less efficient passive PFC would have a PF value of about 0.75 (75%) while equipment with no PFC would score about 0.5 (50%).

The T480-U01 uses active-PFC and rates at up to 0.99 (99%).

OCP, OVP, SCP, ESD: The "deadly 4". The T480-U01 provides inbuilt protection against over-current, over-voltage and short-circuit damage. It also shrugs off electro static discharges up to 3000V.

Lifetime (MTBF): The MTBF or Mean Time Before Failure is a pretty meaningless number due the lack of consistency in testing methods but I think it's fair to assume this as an average "minimum" lifespan, with the emphasis being on the word average.

Noise Control: Most power supplies these days come with some kind of thermal fan control to help minimise noise. Tagan use what they call "TSCT" or Tagan Silence Control technology, which it's claimed offers an operational volume of only 22dBA at up to 50% load rising to a mere 33dBA when flat out.

DC Output: It's a lot easier to make a power supply and its price tag look good by offering fairly tame DC outputs. That's clearly not the case with the Tagan as, although you can find slightly higher +3.3V outputs if you look hard enough, the 48A available on the +5V line is bordering on scary.

Perhaps one of the obvious competitors to the Tagan is Antec's excellent True Power range. Just for the hell of it, here's a few spec comparisons between the Tagan and the True 480, both 480 watt units:

Nip and tuck in most cases but the Tagan has the higher outputs and higher efficiency rating. The Tagan also has a higher quoted MTBF, for what it's worth, and a better hold-up time. It comes second best in terms of its load regulation.

Time to take a closer look at the unit itself.

In The Box