Introduction

Thermaltake has something interesting for us today, it's their take on the entry level modular cable PSU. Assuming you're willing to call a 750w PSU entry level anyway. The idea is a nice one, but the real question is: Can this unit do battle with the king of cheap/functional units? We'll find out!

We've seen quite a few different products from Thermaltake here at Funky Kit, ranging from meh all the way through AWESOME! Before we go further, let's give Thermaltake a block of text to play with. (From their About Us page)

Sounds good to me! It doesn't answer the question of this power supply though, so let's focus on that for the time being.

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<hrdata-mce-alt="Features and Specifications" class="system-pagebreak" title="Features and Specifications" />

Features and Specifications

Direct from Thermaltake's product page for the Smart-M 750w power supply.

There's a fair bit of good stuff here! 750w continuous at 40c is nice to see, as is 80+ Bronze and at least one Japanese capacitor. More than one would be ideal of course! Double-forward switching used to be the top of the heap, when 80+ bronze was the top of the heap. Now it's functional and effective, but nothing to write home about. DC-DC regulators for the 5V and 3.3V rails is nice, Active-PFC I love, flat cables are my favorites. If a 750w PSU doesn't support multiple graphics cards, don't even think about buying it. Lastly, I'm all for protections!

80 Plus Certified

SMART Modular Bronze series saves energy through its high energy efficiency of up to 85% and is 80 PLUS® Bronze certified. •ErP Ready: New SMART Series fulfils the EU guideline for ErP (Energy-Related Products) implemented in 2010 • Supports Energy Star 5.0* energy standard: SMART Modular Bronze Series is suitable for use in Energy Star-compatible computers. •Supports Intel Deep Power Down C6 Status: SMART Modular Bronze Series helps your PC system operate more power efficiently. • Corresponds to the EU directives on WEEE and RoHS: Thermaltake considers its full impact on the environment during manufacturing and maintains green facilities to ensure SMART Modular series meets WEEE & RoHS requirements.

ErP is another thing I like, it roughly translates to using little to no power when the unit is turned off. This assumes of course that you don't have anything charging off USB. You can't blame the PSU if it's you drawing power!

Connector wise we have a good selection, six Molexs, nine SATA and four PCIe. Plus Motherboard and CPU of course!

The output chart looks great, part of why I'm a big fan of DC-DC units is their ability to put out almost their entire wattage on the 12V rail(s). Some can't, but it's rare.

The protection points for OVP/UVP aren't great, I'll be curious to see what IC this is. Most modern protections ICs are tighter than that.

900w peak is a lot, but I don't test (or look for) peak watts. They're best ignored in my opinion. Let's check the box out.

<hrdata-mce-alt="Photos: The Packaging & Contents" class="system-pagebreak" title="Photos: The Packaging & Contents" />

Photos: The Packaging & Contents

This is a pretty nice looking box, really. Like it says itself, no gimmicks.

The rear has more on it, including a picture of an IC that isn't overly related to the caption in function (it sort of is, it's the brains for 5V / 3.3V DC-DC conversion, so it does have some of those protections it in for those rails). Other than the pictures and the fan/efficiency charts, we just finished reading through this information.

On one end we have a picture, on the other we have the basic features in 13 languages. That seems slightly excessive, but I certainly won't dock points for it.

Opening the box, we find... Pamphlets, mostly. The PSU is in the bubblewrap, there are some modular cables to the left.

It's not the world's best packaging, but it's quite decent. I rate it "good enough".

The modular cables come inside this sack, it closes with hook+loop fasteners (the common name of which is trademarked...).

Inside the sack we have a sack. Very meta. Or perhaps it's Sackception now. We used to call it meta. I feel old now.

We do indeed have four 6+2P PCIe power plugs, this is good. We also have the six Molex plugs on two cables and nine SATA plugs on three cables. Those with decent math skills will note that the above adds up to five Molex/SATA cables. Those who scroll up will note that there are four plugs. Looks like you'll have to choose between nine SATA and six Molex and decide which is more important for you. I find this a bit odd, really. We also get a Molex-FDD adapter.

We also get a power cable, four screws and some one-use cable ties (yup, another patent). The power cable isn't exactly beefy, but it's rated for more than enough amps.

<hrdata-mce-alt="Photos: The PSU itself" class="system-pagebreak" title="Photos: The PSU itself" />

Photos: The PSU itself

Inside the bubble wrap sack ... we find the PSU to look something like the box. I like it.

Don't squeeze the grill, the downside to this grill is that it can be bent if you squeze it. The upside is that it'll keep dropped screws (and cables) out. I've seen people drop screws in on accident a couple times, it's a real day ruiner. The warranty sticker is rather excessive in my opinion, it could be smaller.

That shiny sticker is courtesy of Ultra, the company that came up with the modular cable concept. They patented it, and forced companies to buy the right to the patent and put that sticker on. Annoying. Amusingly, Ultra had their modular patent rejected in 2011, Thermaltake likely didn't need to pay them for the annoyingly shiny sticker.

On the modular output side we have six plugs and fairly clear lables, works for me. As a note, for hardwired cables we have only the motherboard 20+4P connector and the CPU 4+4P connector! Perfect! Thank you, Thermaltake. It does make me wonder how we're supposed to plug five peripheral cables into four plugs though.

I spy a CWT unit. Most likely anyway, we'll see for sure when it gets ripped apart. I find this to be promising, CWT has some very nice designs out there.

Now that we've seen it, let's test it!

<hrdata-mce-alt="Load Testing" class="system-pagebreak" title="Load Testing" />

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.

The 12 V rail managed 1.07% regulation, just the tiniest hair over the magical 1% lin. 5 V came in at 1.2%, while 3.3 V only managed 1.8%. All told we get an average of 1.36% regulation, very good for the price range. Up till recently it would have been fantastic for most any price range! How things change.

The fan slowly ramped up with the load, at low and mid loads it is very quiet. At full load it sounds like a fan, no real surprises there. The unit can do full load and ~40c intake temperatures without any issues, it seems to be a solid piece. Let's check out the ripple.

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

We'll start with zero load, 12V then 5V then 3.3V. In all three shots the scope is set to 10 mV/div and 10 microseconds/div.

12 V:

Right about 20 mV. Nice.

5 V:

22mV here. Not bad at all.

3.3 V:

Roughly 28mV here. A bit more than I'd like to see, but well within spec.

Full Load

Next up, full load! Same 10mV/10microsecond scope settings. Same cold intake air.

12 V:

~52mV of ripple. Very good.

5 V:

64mV, that's 14mV over spec. Not good. Will it cause issues? Probably not. Am I going to let it slide? Not really. Is it enough for me to sack the unit? No.

3.3 V:

36mV on the 3,3V rail. That's perfectly acceptable.

Full Load +

Into The Enclosure of Unreasonable Warmth it goes! The following shots are with the unit at full load and suffering through 40-41c intake air temperatures. The scope is set to 20 mV/div and 10 microseconds/div. Note that this is twice the vertical scale of the previous results!

12 V:

~60mV of ripple here. Not perfect but far from bad. Pretty good, really.

5 V:

72mV here, 22mV over the max allowed spec. Blegh. Will it kill things? No. Will it cause instability? Doubt it. Will I score against the unit for this? Yes.

3.3 V:

46 mV here, that's a pass. Only by 4 mV, but a pass is a pass, it's just 5 V that has issues.

Let's take this thing apart and see if there are any obvious issues inside.

<hrdata-mce-alt="Dissection - Part 1" class="system-pagebreak" title="Dissection - Part 1" />

Dissection - Part 1

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 can kill you. Don’t try this at home. Don’t try this at work. Just don’t do it.

With the top removed we can see the fan hub:

Despite the Thermaltake label, this is a Yate Loon fan. It has ball bearings, so it'll last a very long time indeed.

An overview of this unit screams "CWT!". It's roughly the same platform as the Corsair TX750M, and from looking through the grill perhaps the CX750M as well. The main difference between this and the TX750M is in the secondary section, which we'll get to soon enough.

First up is the transient filter:

Photographing the transient filter rarely works this well, we can see everything in a single photo! Four Y caps, two X caps, two inductors, one TVS Diode, one fuse, one EMI shield. This is a good looking transient filter.

Next up, the APFC bits.

The APFC brain is a CM6800TX, a very common and effective (if not wildly efficient) PCF/PWM controller. It runs both the APFC bits and the PWM bits.

For rectifiers we have a pair of GBU606 (6a, 600v) units.

After that comes a pair of K20J60U (20a, 600v) MOSFETs (note the green thermister poking into the picture, it's part of the APFC too, in charge of inrush protection).

They're followed by this QH08TZ600 (8a, 600v) diode.

The primary capacitor is a nice big Panasonic piece, very Japanese.

After that come the primary switches, a pair of P18N50C MOSFETs. I can't find a datasheet for them, but if they follow the general naming conventions theyre 18 amps and 500 volts.

5VSB gets a single HFS3N80 (3a@25c, 1.9a@100c, 800v), I can't find the brains in charge of 5VSB operation.

On the secondary side we have six 6x AP9990GH-HF-3(100a@25c, 70a@100c, 60v) MOSFETs wired for synchronous rectification.

The TX750M uses schottky diodes, chalk up a victory for Thermaltake on that one. On the left is a black wire leading to the fan control thermistor.

<hrdata-mce-alt="Dissection - Part 2" class="system-pagebreak" title="Dissection - Part 2" />

Dissection - Part 2

This being a DC-DC unit, the 5 V and 3.3 V rails are generated off the 12 V rail, this is done on the modular output board by a APW7159. Each rail gets three AP72T03GH (62a@25c, 44a@100c, 30v) MOSFETs.

The 5VSB rail gets a single 1040CTP Schottky rated at 10 amps and 40 volts, no heatsink on it though so don't start thinking you can get 10a out of the 5VSB line, you won't.

Protections are care of a WT7502V IC. The protection trip points are somewhat nicer than what Thermaltake said. Still not the tightest control in the world, but I've seen worse.

The modular board looks thusly:

Those two polymer caps (per rail) are all the 5 V and 3.3 V rail get, clearly it's not quite enough for the 5 V rail. Polymers are nice, but there is something to be said for the raw bulk energy storage of electrolytics. Of course, I didn't put a 20 amp load on the 3.3 V rail (only 6.67 A) and it was still right at the limit. This may just be a noisy DC-DC setup.

Just in front of the two inductors on the inside of the case there is a strip of copper EMI shielding.

Soldering overall is good, there are only a couple issues.

Bit close there in my opinion.

When your soldering has miniature troll caves in it, you have issues. Note the pulled up trace too! Before you get too far up in arms, remember that this unit passed testing and both ends of the trace are still glued to the board. Still, disappointing.

The PCB UL number (it has one!) is E206420, which traces to "DONG GUAN NEW ENERGY PRINTED CIRCUIT BOARD CO LTD" whoever that is. The case's UL number is E161451, which belongs to Channel Well Technology, aka CWT. No real surprises there.

That does it for the guts, things look pretty good in here other than the troll cave.

<hrdata-mce-alt="Verdict and Conclusion" class="system-pagebreak" title="Verdict and Conclusion" />

Verdict and Conclusion

All told, I'm fairly impressed. This is a solid PSU at a good price point. Let me elaborate:

The connector selection is good, though you'll have to chose between 9 SATA and 6 Molex plugs and decide which you'd rather have. Only 12 plugs worth of peripheral cables can be plugged in at once. You do get four PCIe 6+2P plugs though, this is good.

Regulation is very good indeed.

Ripple control on the 12 V rail is good, ripple control on the 5 V rail fails by 22mV, almost 50% over the limit. The 3.3 V rail stays within spec, barely. This is unfortunate, though not a total dealbreaker.

The fan isn't bad at all, and it's a ball bearing unit that should last a very long time.

I like how the unit looks, it appeals to me. I also like that it has a grating keeping dropped screws and cables out of the PSU.

The soldering is good overall, but there are a couple issues. One small and easy to ignore, the other somewhat larger and uglier.

This unit is priced quite well, there aren't any units currently available in this performance/efficiency bracket (~$90) that are cheaper. There is one unit the same price, but the Smart-M has a $20 mail in rebate on it and the other doesn't. Everything else costs more.

All told there are pros:

• Modular cables.
• Good price.
• Looks nice.
• Fan grill keeps screws and cables out.
• Very good regulation.

There are some cons too:

• Soldering could be better.
• 5 V rail has 22mV of ripple over the spec.

Final Words: All-in-all, Thermaltake Smart-M 750W Modular Power Supply is a very good unit with only a few minor issues. I give it an overall rating of 8/10. If you need 750w of Bronze power with modular cables, this is a solid choice.

SCORE
8/10

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