Enermax NAXN ADV 650 W Power Supply Review

Previously we looked at a massive (1500 W) Enermax unit, today’s unit is a rather more reasonable 650 W. It also has something interesting, flat cables. Not just flat cables for some connectors, but flat cables for all the connectors! Even the ATX24P connector! Everything! That’s a rather interesting idea if you ask me. Beyond that we also get 80+ Bronze and a sub-$100 price tag, putting this unit straight into what is arguably the toughest price bracket. How will it match up with the competition? We’ll find out!

Features

Direct from Enermax’s product page for the NAXN ADV (not to be confused with a mere NAXN, mind you), we have the features list! My thoughts are in grey italics.

Efficiency

• 80 PLUS® Bronze
  84 to 88 percent efficiency at 230V and 20 to 100 percent load. 80 PLUS® Bronze certified.
• ErP Lot 6 2013 ready!
  Help systems to meet the latest EU eco-design directive ErP Lot 6 2013 (< 0.5W in standby mode*) due to an improved, high-efficient 5V standby (+5Vsb) circuitry.
  *only in combination with an ErP Lot 6 2013 ready mainboard
• ENERGY STAR 5.0 ready!
  Support computer systems to meet ENERGY STAR 5.0 standard.

Included in the delivery

• NAXN 82+ Advanced power supply
• AC cord
• Cable ties
• 4 screws
• User Manual

Pretty specific list there. We’ll check that stuff out in the Cables section. Before we get to that though, we have specifications.

Specifications

600 W of 12 V on a 650 W unit implies a classic layout rather than the bleeding edge DC-DC bits. Not surprising considering the price and market. No word on how long the peak power can be sustained.

Cables & Connectors

		ETL450AWT	ETL550AWT	ETL650AWT
ATX12V 20+4 Pin		1x (55cm)	1x (55cm)	1x (55cm)
CPU 4+4 Pin		1x (60cm)	1x (60cm)	1x (60cm)
PCI-E 2.0 6+2 (8)Pin		2x (50cm)	2x (50cm)	4x (50cm)
SATA		7x	7x	7x
4P Molex		3x	3x	3x
FDD		1x	1x	1x

Pretty good connector selection, I’d like another Molex or two personally but I suspect most people won’t care.

Enough with the text, it’s picture time!

Photos Part One: The Box

The box is a fairly unassuming and fairly small affair, not a whole lot going on. The rear does mention a Japanese Capacitor (no s), making me a bit concerned about the specs page and its “Japanese Capacitors” bragging point. The box is fairly informative however, which gains it points in its favor.

Photos Part Two: The PSU

The box is a minimalist affair inside, a couple partitions and a foamed bubble-bag are about all we get.

The PSU arrived looking happy enough though, so the box is apparently good enough.

Of note on the PSU itself are the fan grill (aerodynamically perfect and patented, mind you), the crackle/matte black/grey finish (looks good, feels good), and the flat cables. Peeking through the exhaust grill didn’t get me very far manufacturer wise, but it did point out that it’s a group regulated PSU. Also note the little loops under the wall power plug, that’s where the cord retainer clips on.

Photos Part Three: The Cables

The cables really are all ribbon style cabling. To keep the ATX24P cable from getting out of hand Enermax used four sections of six pin ribbon, this gives it far greater flexibility than a single 24-pin ribbon or two 12-pin ribbons. Everything else is ribbon cable as well of course! The accessory pack is a bit limited, consisting of four paint gouging silver screws, one power cord (long!) and a power cord retention clip. One thing to note about the power cord is that it is a very tight fit in the PSU. This is excellent, but make sure you’ve gotten it all the way in. Being a tight fit makes the retainer of dubious use, but your mileage may vary on tightness and having the retainer is a nice touch. Usually you only see that on server class PSUs.

Load Testing Part One: Regulation

A decent load test of a PSU requires a decent load. Contrary to what some may believe, that means you need a known load that can fully stress the PSU. Computer hardware does not cut it. Worse, if the PSU fails during testing it might take out the computer hardware anyway. Commercial load testers cost a lot of money. I do not have a lot of money, so I built my own with juicy power resistors and a Toyota cylinder head. It works great. I’ll be using it to load this thing down fairly severely and will check voltages and ripple (more on that later) at various points. The down side to my tester is that the loads it can put on PSUs are fairly coarse, they go in increments of 48 W for 12 V, 50 W for 5 V and 22 W for 3.3V. Those wattages assume the PSU is putting out exactly the official rail voltage, a PSU putting out 12.24 V rather than 12 V will be at 49.9 W per step rather than 48 W. I file that under the “tough beans” category as I figure if a percent or two of load makes that much of a difference, the PSU manufacturer should have hit the voltage regulation more squarely. It does make calculating efficiency difficult at best.  However, given that the input power is read via a Kill-a-Watt, the efficiency numbers are dubious to begin with. Kill-a-Watts are not known for extreme accuracy on things with automatic power factor correction. For this reason, I am not listing the efficiency.

The ATX spec says that voltage regulation must be within 5% of the rail’s official designation, regardless of load. It doesn’t actually mention that the PSU shouldn’t explode, though I expect they figured it was implied. Exploding is a failure in my book regardless.

It is also worth knowing that I will be testing this PSU at both outdoor ambient temperatures (typically between 10 °C and 20 °C here this time of year) as well as in the Enclosure of Unreasonable Warmth. TEUW is a precision engineered enclosure that I use to route the exhaust air from the PSU right back into the intake fan, it is adjustable to hold the intake air temperature at (almost) any level I want it. This way I can test the PSU’s response to hot conditions as well as cold conditions. For the hot testing I will be running the intake temp as close to the unit’s maximum rated temperature as possible. TEUW, in case you’re curious, is a cardboard box. Sometimes a Styrofoam medical supply shipment cooler, if the unit is too efficient for the cardboard box.

Definitely group regulated, but it did a decent job of things. On the 12 V side we have 3.68% regulation. While not epic that’s well inside the +/-5%, also well within the 5% total deviation I want to see. The 5 V rail has a rather impressive 0.6% regulation, making me wonder a bit about what the builders of this unit had in mind when they put this unit together. The 3.3 V rail runs a middle of the road 2.1%. Combined that gives us an average of 2.1%, not bad for a group regulated unit. Not epic either, but totally functional.

The fan makes a bit of noise at idle, at full load it definitely makes it presence known. The idle noise is a combination of airflow noise and ball bearing noise (not offensive in my opinion), at full load it’s almost entirely airflow.

Load Testing Part Two: Ripple

Ripple is fluctuation of the PSU’s output voltage caused by a variety of factors. It is pretty much impossible to have zero ripple in a SMPS computer power supply because of how a SMPS works, so the question is how much ripple is there? In the regulation testing phase we found out how the PSU does at keeping the average voltage at a set level, now we’re going to see what that voltage is doing on really short time frames. The ATX spec says that the 12 V rail cannot have more than 120 mV peak to peak ripple, the 5 V and 3.3 V rails need to stay under 50 mV.

If that isn’t complicated enough for you, there are three forms of ripple to keep track of as well. Long-term ripple from the PSU’s controller adjusting the output voltage and over/undershooting, correcting, overshooting, etc. Medium-term ripple from the voltage controller charging and discharging the inductor(s) and capacitor(s) that make up the VRM, and very short-term ripple caused by the switching itself. The first and second forms are the most important, if they are out of spec it can cause instability at best or damage in extreme situations. The very short-term (I call it transient ripple) flavor is less crucial, excessive amounts can still cause issues though it takes more of it to do so. The ATX spec does not differentiate, as far as the spec goes 121 mV of transient ripple is just as much of a failure as 121 mV of medium or long term ripple.

I test ripple in a few difference ways, first I test it during the cold load testing. It is tested at zero load and maximum load first. During the hot load testing I test the ripple at maximum load again. I have recently started testing ripple at fairly random loads with the unit still hot, it’s a bit unorthodox (a bit? maybe a lot) but has found issues in the past that did not show up with other test methods.

Zero load first, with cold ambients, all scope shots are at 10mV / 5ms.

Not much to see here! The 5 V is weird looking, but everything is well within spec.

Full load, cold ambients:

Well within spec on all counts, the 12 V is a bit over half the maximum allowed while  5V and 3.3V are a bit under half. Good all the way around.

Lastly, full load and 39 °C ambients:

When hot the 3.3 V rail picks up some transient spikes, but it’s still well within spec.

No issues in this section at all, though nothing amazing either. It looks like a pretty standard, properly designed, group regulated PSU. Solid ripple control.

Dissection

Disclaimer: Power supplies can have dangerous voltages inside them even after being unplugged, DO NOT OPEN POWER SUPPLIES. It’s just not a good idea. Opening a power supply and poking around inside could very well kill you. Don’t try this at home. Don’t try this at work. Just don’t do it.

Which is to say, do as I say, not as I do.

After scratching my head for a while trying to drag the name of this platform out of the depths of my brain I asked some fellow reviewers, CWT is the company of the moment for this unit. From this angle it looks like Teapo caps on the secondary and a Nippon Chemi-con on the primary. You’d be partially correct in that guess, the primary cap is indeed a Japanese Nippon Chemi-Con. The secondary side gets a mix of CapXon and Aishi, while the miscellaneous caps are Jun Fu. That’s one (1) Japanese capacitor, so much for the specs and features page. The box got it right though, so that’s something.

The transient filter has two X caps, four Y caps, three inductors, a fuse, and a TVS Diode. That’s one inductor beyond the minimum for a complete filter, so no issues here, I approve.

The APFC is headed by a CM6800TX APFC/PWM controller. No big surprise here as the CM6800 line being is most common by far in Bronze PSUs that I’ve seen. There are a pair of 20N60 (20Av 600V) MOSFETs doing the APFC switching and a 8S2TH06L (8A, 600V) diode to keep things going in the proper direction. Plus of course the NCC primary cap. Rounding things out is a thermistor for inrush protection. So far, this looks like a solid entry level unit.

The 12 V rail gets four 40V60CT (40A, 60V) schottkys, 5 V gets a single 30L45CT (30A, 45V), 3.3 V gets a single STPS60L30CW (60A, 30V). For those of you keeping track at home, both 5 V and 3.3 V rails are rated at 20 amps, which makes the huge difference in ratings a bit odd but not a problem by any means. Somewhat more concerning are the CapXon and Aishi capacitors, including some CapXons in Teapo colors. The Jun Fu caps are all on minor stuff, which is good as they’re not good caps. CapXon is about as low in the capacitor pile as I’m willing to go, Aishi I can’t find much information on. All three brands are Chinese. The protections IC only supports OVP/UVP, leaving the unit to rely on the CM6800TX for SCP, OCP, and SIP. It looks like SCP and OCP are essentially the same thing as far as the CM6800 is concerned. What SIP is I still don’t know.

Lastly, the soldering:

Main PCB soldering is quite good, no meaningful issues. The receptacle soldering is a different story however.

Flaked off solder mask in the lower left, incomplete heating/soldering on the lower right. That’s disappointing. The IC there discharges the capacitors when AC input is removed, it replaces the classic bleed resistors, gaining some efficiency.

Final Words and Conclusion

The basic premise offered by the NAXN ADV is good. The execution I find a bit frustrating.

The ribbon cables are great, they slot through small spaces easily and hide behind the motherboard tray quite easily. The ATX24P connector being ribbon cable is a New and Different thing that I like a lot. Having a standard cable for that and ribbon for everything else has always looked weird to my eye. Being all ribbon cables elevates the cable management capabilities of this PSU into the realm of modular units.

The price however is also in the realm of modular units. At the current price of $99 it costs about $20 more than most other 80+ Bronze 650 W non-modular PSUs. For that matter it’s about $10 more expensive than some 80+ Bronze modular PSUs. That puts the price for having ribbon type cables fairly high. Also important to note, some of those modular and non-modular units use Japanese capacitors throughout, rather than the mid to low bin Chinese capacitors in the NAXN ADV. $20 and capacitor quality is a bit much to give up for ribbons I think.

The looks are fantastic, I really like the finish, I really like the logos on the sides, I really like the ribbon cables, the fan guard looks cool too.

Other than the capacitors, the component choices are odd at times (massive 3.3 V rectifier!) but solid. The capacitors range from OK-ish through Jun Fu, which is another word for junk. To be fair the Jun Fu caps are scattered around the primary side doing relatively light duty, but Jun Fu is Jun Fu, and that’s still another word for “Junk Capacitor”. The CapXons on the secondary side are more reasonable, but a decent Chinese capacitor is still well short of a decent Taiwanese capacitor (Teapo, for instance), and well short of  Japanese capacitors. The Aishi caps I know little about, I’m unceremoniously lumping them in the same bin as the CapXons. Lastly (for caps, anyway) I find it mildly frightening that CapXon is imitating Teapo’s colors, usually companies aim a bit higher than that.

Regulation is best described as “good”. It’s not epic, it’s not bad, it’s not really worth spending much time talking about in either direction.

Ripple control is good as well, pretty much the same deal as the regulation.

The soldering on the main PCB is excellent. The soldering on the receptacle is not. It’s rather bad, really. The unit functioned like that, but I’m disappointed in Enermax and CWT.

The fan is typical for Yate Loon ball bearing bits, it has bearing noise at low speed (not a lot) and isn’t exactly quiet at full speed. Very typical of a unit in this general range.

The connector selection is good overall, four 6+2P PCIe plugs means you can run dual high end GPUs and the PSU can back that up with enough wattage as well. I’d like a couple more Molexes for my purposes.

Let’s summarize a bit and squeeze all the above into a few easy to digest bullet points!
There are pros:

• All cables are ribbon cables!
• Looks great.
• Solid connector selection.
• Ripple control and regulation well within spec.

There are cons too though:

• Price is at least $20 too high for performance and capacitor selection.
• Soldering issues on the receptacle.
• Capacitors range from “vaguely decent” through “junk”.

At the bottom line, Enermax needs to either swap the caps out for Teapos (or better) or cut the price $20-$30 to make this a Really Good Buy. As it is you’re paying for those ribbon cables with both dubious capacitors and a significantly higher price than the competition. If the cables are worth it to you, it’s a perfectly functional PSU, but I’d wait for it to go on sale or for Enermax to kick the capacitor quality up a couple notches.

Despite absolutely loving the looks and the ribbon cables (even the main motherboard connector!), I feel that the cons are too hefty for an Approved badge. I don’t like paying an extra $20 for significantly lower quality capacitors, so today we have a meh.

For more about what exactly it means, click the meh.

—Bobnova