Antec Earthwatts EA 750W green Review

1. Introduction2. Antec Earthwatts EA 750W (External)3. Antec EarthWatts EA 750W (Internal)4. Testing Methodology and Results5. Closing Thoughts6. View All Pages

Antec have been releasing some great products lately, many of which have been reviewed on these very pages. I personally really like their latest Kuhler 620 and 920 liquid coolers and the Rockus speakers certainly hit the spot. They are updating their mainstream ‘high value for money' power supplies and today we are looking at their latest 750W unit.

The Earthwatts EA 750W is supplied without a power cable, a move which won't appeal to everyone. Antec are aiming these models as ‘upgrade' units. I spoke to them when they sent over the 650W and 750W units and they felt that many people already have several power cables and that another could be deemed as an unnecessary extra. As I said before, there is certainly a tinge of helping ‘mother earth' to the whole concept but it bewilders me. Best to just get into the review.

So whats new with this latest model? Antec are still using Delta as their OEM partner, but the latest range is 80 Plus Bronze Certified. The new units are ‘green' and they have received some performance improvements. The 750W we are reviewing today is also equipped with a larger fan, always a good sign.

EarthWatts 750W overview:

• 750 Watts of continuous power
• Nvidia SLI certified, ATI CrossFireX certified
• 80 Plus Bronze Certified – up to 88% efficient
• Four +12V rails
• Up to 100% power available on +12V rails
• Quiet 135mm fan
• ATX 12V version 2.3 and EPS12V version 2.91 compliant
• Active PFC with PF: 0.99
• MTBF: 100,000 hours
• Meets 2010 EUP requirement: 5Vsb < 1W
• Safety: cUL, TUV, CE, CB, FCC, C-TICK, CCC, BSMI, Gost-R

The Antec EarthWatts 750W arrives in a traditionally styled Antec package.

The bundle is rather spartan with a manual and some screws supplied. The PSU is protected in a bag with a cardboard piece on each side. As you can probably tell from the picture, it isn't a modular design.

We like the design of the new power supply. The army style camouflage green looks very nice and is a vast improvement when compared to the older ‘plain grey' design.

The rear of the unit is vented to allow for maximum airflow, there is a power switch above the connector port.

The fan on this specific model gets an upgrade, to a new 135mm unit. It is plain black to maintain a simple two tone appearance.

Antec EarthWatts 750W Power Supply
DC Output	+3.3V	+5V	+12V1	+12V2	+12V3	+12V4	-12V	+5Vsb
Max Output	25A	25A	40A	40A	40A	40A	0.5A	3A

This design has four +12V rails, each of which offer 40A.

Cable	Amount
MB 20+4 pin	x1
CPU 4+4 pin	x1
PCI E 8 pin (6 pin +2)	x4
Sata power connectors	x9
Peripheral 4 pin (molex)	x6
Floppy connector	x1

This model gets a fan upgrade, and very nice it is too. They have included an ADDA ADN512UB-A90 which has also been used in some of the recent XFX power supply designs. This 135mm fan has nine blades and is a ball bearing design which runs off 0.44A. It is rated to produce a maximum of 82CFM.

The Delta design is very clean and well laid out, positioning several heatsinks to help with component cooling.

The supply uses two primary Nippon Chemi Con capacitors – 270uf 420V and rated to 85C. The design is Active PFC and offers over current, over voltage, short circuit, over power and over temperature protection. The cables are sleeved, tied together and then routed into the chassis, helping to stop fraying against the metal body.

Additional technical assistance: Peter McFarland and Jeremy Price.

Correctly testing power supplies is a complex procedure and KitGuru have configured a test bench which can deliver up to a 2,000 watt DC load. Over the coming months this configuration is likely to be adjusted further and fine tuned. Due to public requests we have changed our temperature settings recently – previously we rated with ambient temperatures at 25C, we have increased ambient temperatures by 10c (to 35c) in our environment to greater reflect warmer internal chassis conditions.

We use combinations of the following hardware:
•  SunMoon SM-268
•  CSI3710A Programmable DC load (+3.3V and +5V outputs)
•  CSI3711A Programmable DC load (+12V1, +12V2, +12V3, and +12V4)
• Extech Power Analyzer
• Extech MultiMaster MM570 digital multimeter
• Extech digital sound level meter
• Digital oscilloscope (20M S/s with 12 Bit ADC)
• Variable Autotransformer, 1.4 KVA

We are combining 12V output into a single result.

DC Output Load Regulation
Combined DC Load	+3.3V		+5V		+12V		+5VSB		-12V
	A	V	A	V	A	V	A	V	A	V
75W	1.22	3.35	1.19	5.12	4.90	12.06	0.50	5.03	0.20	-12.05
150W	2.18	3.34	2.80	5.09	10.00	12.04	1.00	5.02	0.30	-12.04
375W	6.15	3.32	6.00	5.06	26.10	12.03	1.50	5.01	0.50	-12.04
565W	10.30	3.30	10.87	5.03	38.34	12.00	2.00	4.99	0.60	-12.04
750W	10.74	3.28	13.86	5.01	53.51	11.98	3.00	4.98	0.80	-12.03

The EarthWatts shows to have good load regulation. These are great results and the +3.3V and 5V rails remained firmly within +/-2% of the nominal voltage instead of the recommended +/-5% and the +12V rail held within +/- 1%, even when it was forced to deliver over 53 Amps.

EarthWatts 750W Green	Maximum Load
	803W

We managed to reach around 803W before the unit would shut down gracefully, after the protection kicked in.

Next we want to try Cross Loading. This basically means loads which are not balanced. If a PC for instance needs 500W on the +12V outputs but something like 30W via the combined 3.3V and +5V outputs then the voltage regulation can fluctuate badly.

Cross Load Testing	+3.3V		+5V		+12V		-12V		+5VSB
	A	V	A	V	A	V	A	V	A	V
734W	1.0	3.32	1.0	5.04	60.0	11.95	0.2	-12.03	0.50	5.01
154W	15.0	3.29	15.0	4.98	2.0	12.01	0.2	-12.04	0.50	5.00

Much like the 650W model, the fluctuation is held safely within the rated parameters, even when we load the 12V line with 60A.

We then used an oscilloscope to measure AC ripple and noise present on the DC outputs. We set the oscilloscope time base to check for AC ripple at both high and low ends of the spectrum.

ATX12V V2.2 specification for DC output ripple and noise is defined in the ATX 12V power supply design guide.

ATX12V Ver 2.2 Noise/Ripple Tolerance
Output	Ripple (mV p-p)
+3.3V	50
+5V	50
+12V1	120
+12V2	120
-12V	120
+5VSB	50

Obviously when measuring AC noise and ripple on the DC outputs the cleaner (less recorded) means we have a better end result. We measured this AC signal amplitude to see how closely the Antec unit complied with the ATX standard.

AC Ripple (mV p-p)
DC Load	+3.3V	+5V	+12V	5VSB
75W	5	5	15	5
150W	10	10	25	10
375W	15	10	30	15
565W	20	15	40	15
750W	25	15	50	20

Ripple results are very impressive, across the board. The 12V rail registered around 50 mV at full load with our equipment, which is well within the Tolerance guidelines.

Efficiency (%)
75W	83.87
150W	87.65
375W	88.19
565W	87.21
750W	83.65

For a 80 Plus Bronze specified unit, these results are very strong, peaking at just over 88 percent at 50 percent load. At full load the efficiency drops to just under 84 percent.

We take the issue of noise very seriously at KitGuru and this is why we have built a special home brew system as a reference point when we test noise levels of various components. Why do this? Well this means we can eliminate secondary noise pollution in the test room and concentrate on components we are testing. It also brings us slightly closer to industry standards, such as DIN 45635.

Today to test the power supply we have taken it into our acoustics room environment and have set our Digital Sound Level Noise Decibel Meter Style 2 one meter away from the unit. We have no other fans running so we can effectively measure just the noise from the unit itself.

As this can be a little confusing for people, here are various dBa ratings in with real world situations to help describe the various levels.

KitGuru noise guide
10dBA – Normal Breathing/Rustling Leaves
20-25dBA – Whisper
30dBA – High Quality Computer fan
40dBA – A Bubbling Brook, or a Refridgerator
50dBA – Normal Conversation
60dBA – Laughter
70dBA – Vacuum Cleaner or Hairdryer
80dBA – City Traffic or a Garbage Disposal
90dBA – Motorcycle or Lawnmower
100dBA – MP3 Player at maximum output
110dBA – Orchestra
120dBA – Front row rock concert/Jet Engine
130dBA – Threshold of Pain
140dBA – Military Jet takeoff/Gunshot (close range)
160dBA – Instant Perforation of eardrum

Noise (dBA)
75W	27.9
150W	28.3
375W	29.8
565W	33.4
750W	34.2

Noise levels are quite low, with the system only becoming audible in the final 25% of output. Under 400W load it would be hard to know the unit was actually on.

Temperature (c)
	Intake	Exhaust
75W	36	38
150W	36	40
375W	39	46
565W	42	51
750W	44	54

Exhaust temperatures are good, rising to a 10c above ambient result at full load. The 135mm manages to combine a reasonably low level of noise with high airflow.

Maximum load	Efficiency
803W	82.3

For those interested, we measured efficiency when stressing the unit to breaking point. 82.3 percent efficiency at 803W … hardly practical, but interesting regardless.

This range is strictly aimed at a value oriented market and as such it is a success. The overhauled Delta design is very capable, stable and effective, delivering solid load regulation and high levels of efficiency for an 80 Plus Bronze Certified product.

Ripple and noise suppression are also good with this particular unit peaking around 50mV on the +12v output under full load, well within the rated specifications. We never tested the older model for a direct comparison but externally we like the new appearance. Not everyone will warm to the camouflage green paint, but we feel that it really stands out in such a crowded marketplace.

Negatively, we would like to see a semi modular design, especially since this unit would otherwise be attractive to the performance oriented media PC audience. That said, the price point and target market have to factored into the final conclusion. Additionally, the cables are unsleeved, which is slightly disappointing considering that other models we have reviewed before in a similar price bracket have been fully sheathed.

This product should hit retail at around £70-£80 including vat, meaning it is a relatively low cost option for a new system upgrade.

Pros:

• solid all round performance
• efficiency is very good for 80 Plus Bronze
• green paint enhances appearance compared to older ‘grey'
• price point is competitive

Cons:

• cables are not sleeved
• non modular design means it can get messy
• AC power cable seems a strange omission, regardless of what Antec may claim.

KitGuru says: a very solid performer, at a decent price.

Edit: 25 May 2011: Antec informed us that retail models of this particular unit will come with a power cable.

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