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Antec TrueControl 550 PSU

Dec 8, 2002 -- by Mike Chin

Product Antec TrueControl 550
Manufacturer Antec Inc.
MSP ~US$160; TBA

Antec hardly needs any introduction. Over the past few years, the Silicon Valley based company has grown into the biggest PC case and power supply seller in the U.S. That growth is fueled by canny marketing and distribution, aggressive expansion into a variety of product lines, and, of course, good solid products that combine performance and cosmetic appeal for enthusiasts and system builders. The multicolored LED fan, for example, is one of those clever products that was first launched by Antec -- a top seller move that attracted droves of imitators. Yet, despite its gimmicky appeal, their 80mm multicolor LED fan is not a bad fan and has actually been mentioned as a pretty quiet fan in SPCR's demanding forums.

Power supplies remain at the core of their business, however, and the Antec TruePower PSU series has achieved great success since its introduction earlier this year. The dual-fan TruePower series is differentiated from Antec's others as their most advanced PSUs. The key features cited:

  • Dedicated output circuits for 3.3V, 5V, and 12V lines. This means each voltage line can perform up to the specified maximum, without interaction with the loads on the other lines, until the full capacity of the power supply itself is reached.
  • Voltage feedback detection, and tighter performance tolerances. The power circuitry monitors its own output voltages at the ATX connector and adjust its output to compensate for any drop off, including for the resistance found in the wires This feature allows Antec to tighten up their voltage regulation from Intel’s specified ±5% allowable variance to a tighter ±3%.
  • Antec Low Noise Technology, similar to that employed by Seasonic, Zalman, and Nexus, which increases fan speed in an exponential curve so that low noise operation is maintained to middle power levels yet the full cooling power of the fans is brought on line when need at maximum power dissipation.
  • Fan-only output provides other fans in the PC with the same thermally controlled voltage received by the PSU, keeping fan noise to a minimum until cooling is really needed. This is a very useful feature for quiet computing, especially as the nominal voltage supplied stays at a low 5V all the way up to ~100W!
  • Double-ball-bearing fans
  • Gold-plated power connectors
  • Protective nylon sleeving on main power cables

The model under review is a variant of the TruePower line, called the TrueControl 550. Yes, it's a whopper, all right! How is it different from the TruePower? Well, to the above list of features, add:

  • Front panel manual fine control over the +12, +5 and+3.3 voltage lines
  • Front panel manual fan speed control
  • "Convenience" 4-pin Molex power output connector on external back panel for peripheral or convenience use

It is the ultimate control-freak enthusiast modder-hacker power supply. The retail release date for the TrueControl series is set for the New Year, 2003.

These photos are fairly self explanatory. The one above shows the control panel which only occupies one corner of the 5.25" bay bracket. So you don't lose the use of the drive bay completely, the metal chassis is set up to accept a 3.5" hard drive.

In the left photo above, the little knob with the white dot on the right corner of the panel is the fan speed controller. Turn it fully counterclockwise, and the fan speeds are controlled entirely by the thermistor inside the PSU. Turn it clockwise, and the fan speed rises above the default of the thermistor-fed voltage to the maximum of 11V at fully clockwise. The three holes above the knobs are variable trim pots for fine tuning the +12, +5 and +3.3V lines. They are recessed so they can't be casually or accidentally changed.

A screw tool is supplied. That's the other black thing which looks like another knob. It isn't. It is a miniature screwdriver for the voltage line trim pots, as shown in the left photo below. The picture on the right above shows the removable connector on a foot long cable that comes from the PSU and c[plugs into the back of the control panel. Finally the right photo below shows the handy 4-pin Molex +12/5V feed in case you need to power up something on the outside of the case.

These various features mark the TrueControl 550 as one of the most feature-laden PC power supplies ever made. Who would have thought a power supply would push and shove its way to the PC's front panel!

Connectors

There are seven 4-pin Molex connectors and two floppy drive power connectors on three sets of cables, the longest of which is 33" long. That is probably long enough to reach to the farthest hard drive in the tallest case. The main ATX cable, which has a nice patterned mesh cover to keep it tidy, and P4 12V cable are on ~18" cables. There is also the ~2' control panel cable mentioned earlier, two fan-only connectors on ~ 16" cable, and a fan RPM sensing cable for connection to a motherboard chassis fan header in case you want to monitor the PSU fans.

Under the Hood

The heatsinks are decent size, but don't appear to have as much surface area as those used in several other PSUs we've reviewed -- the Zalman, Nexus and Q-Technology. But this unit does have two fans, and the push-pull configuration does provide higher airflow through a high impedance like the innards of this PSU, which is fairly densely packed. Note that the intake grill opposite the 80mm fan is small. I believe this is deliberate, as most of the inflow will come from the 92mm fan. The small size of the intake vents (which are also only as tall as the heatsinks) is to ensure that the air blown in by the 92mm fan does not blow out that way, but rather, is sucked out of the PSU and case.

The 80mm back exhaust fan and the 92mm intake fan are Top Motor brand, which is made by Dynaeon Industrial of Taiwan. Data about these fans from Dynaeon's web site:

Fan
CFM
RPM
Current
DF1208BA 80x25 mm
39.0
34
2900
0.20A
DF1209BA 92x25 mm
57.1
35.8
3000
0.25A

The CFM numbers are a bit difficult to believe, given the current and noise ratings. Neither fan is particularly quiet at 12V.

Published Specifications

Maximum Power

550 Watts

Switches

ATX Logic on-off additional power rocker switch (115/230 Volt selector switch)

Special Connectors

AUX Power

ATX12V

3-pin Fan Sensor

Fan Only

Transient Response

+5V,+12V outputs return to within 5% in less than 1ms for 20% load change.

P. G. Signal

100-500ms

Over Voltage Protection

recycle AC to reset

+5V trip point
+3.3V trip point
+12V trip point

Overload Protection

Latching Protection

+5V @
+3.3V @
+12V @

Leakage Current

Input Voltage

115 VAC / 230VAC

Input Frequency Range

47Hz to 63Hz

Input Surge Current

60A @ 115VAC

Input Current

10.0A for 115VAC

6.0A for 230VAC

Hold-up Time

> 17ms at Full Load

Efficiency

>68%

EMI/RFI

FCC Class B CISPR22 Class

OUTPUT

+5V

-5V

+12V

-12V

+3.3V

+5VSB

Max. Load

40A*

0.5A

24A

1.0A

32A*

2A

Min. Load

0A

0A

0.8A

0A

0A

0A

Load Reg.

±3%

±5%

±3%

±5%

±3%

±5%

Ripple V(p-p)

50mV

50mV

120mV

120mV

50mV

50mV

* +5V, +3.3V & +12V maximum output 530 Watts max.

TEST METHODOLOGY

Parameters Tools
DC load on PSU DBS-2100 PSU load tester
Ambient temperature
Any number of thermometers
Fan voltages / Voltage regulation
Heath / Zenith SM-2320 multimeter
AC power
Kill-A-Watt Power Meter
Noise
Heath AD-1308 Real Time Spectrum Analyzer

The core PSU test tool on SilentPCReview's test bench is the DBS-2100 load tester, made (in Taiwan by D-RAM Computer Company) specifically for testing computer power supplies. The machine consists of a large bank of high power precision resistors along with an extensive selection of switches on the front panel calibrated in Amps (current) and grouped into the 5 voltage lines: +5, +12, -12V, +3.3, -5, +5SR. Leads from the PSU connect into the front panel. It is shown above with leads from a PSU plugged in.

To ensure safe current delivery, the DC output connector closest to the PSU on each set of leads is hooked up to the load tester. This ensures that the current delivered is distributed to as many short leads as possible. When pushing a PSU to its rated output, the heat generated in the wires can be an issue.

The PSU is tested at 4 DC output power levels:

  1. 22.5W: The total of the minimum load that can be applied on each voltage line.
  2. 90W: Established previously as a typical max power draw of a mid-range desktop PC.
  3. 150W: For higher power machines.
  4. Maximum: The rated maximum power of the PSU.

Care is taken to ensure that the load on each of the voltage lines exceed the ratings for the tested unit. The PSU is left running at least 10 minutes at each power level before measurements are made.

The DBS-2100 is equipped with 2 individually fused AC outlets and 4 exhaust fans on the back panel. A bypass switch toggles the fans on / off so that noise measurements can be made. The resistors get very hot under high loads.

Kill-A-Watt AC Power Meter is plugged into the AC outlet on the side of the DBS-2100 in the above picture. The AC power draw of the PSU is measured at each of the 4 power loads. The efficiency of the PSU at each power level is calculated thus: divide DC power output by AC power consumption. It always varies with load, and also temperature. PSUs seem to run more efficiently when warmer, up to a point.

The Heath / Zenith SM-2320 multimeter, a fairly standard unit, is used to measure fan output voltages and the line voltages of the PSU output. The latter is done via the terminal pin on the front panel, above the connections for the DC outputs from the PSU.

The Test Lab is a spare kitchen measuring 12 by 10 feet, with an 8 foot ceiling and vinyl tile floors. The acoustics are quite lively. The PSU under test is placed on a piece of soft thick foam to prevent transfer of vibrations to the table top. Temperature in the lab is usually 20C or lower. This is something of a problem as PSUs usually operate in environments that easily reach 45C.

In-case Thermal Simulation

Sited next to or above the CPU, the PSU is always subject to external heat. The low ambient temperature of the test lab explains why the fan in the last PSU reviewed, the Nexus NX3000, never reached 12V even at full power output for over 20 minutes. I have applied a solution to this problem as promised. The idea was first suggested some months ago by contributor John Coyle in followup communications after the publication of his article, Fanless (or Not) with TKPower 300 & VIA C3. Thanks, John!

The solution shown above is a 100W AC bulb in an empty case with the PSU mounted normally. The distance between the bottom of the PSU and the top of the bulb is about 7-8 inches. The heat generated is roughly equivalent to that produced by a typical desktop. All the back panel holes in the case are blocked with duct tape. The only significant exit for the hot air in the case (once it is closed) is the PSU exhaust, which is then subject to a fair amount of heat, probably a bit more than would be seen by a PSU in a real case because there are usually other exits. The bottom front panel case intake hole is very large. In testing, the front edge of the case is moved so it hangs over the edge of desk, over free air, to ensure good fresh convection airflow. There are no case fans.

A thermistor taped to the bottom of the PSU close to its right front is used to monitor temperature. It's the little blue nub hanging down off the black wire in the photo above. Its temperature is somewhat affected by the airflow of the PSU fans but not directly in the airflow path.

The simulation means the PSU must cope with the 100W of heat generated by the light bulb plus whatever heat it generates within itself. It is a good simulation when the PSU is actually putting out ~100W of DC voltage, although in real-life systems, there would be other air exhausts paths, resulting in a bit lower case temperature. The 100W bulb is a close approximation of the heat that would be generated by components within the case. To simulate actual PC conditions closely, the light bulb power should match the DC power load applied to the PSU. I did not do this. It was too much trouble, and I did not have 150W or other high power bulbs handy. Maybe next time if there is a major clamor about the inadequacy of this simulation.

No PSU Temperature Measurements will be done any more. Originally, it was meant to provide a more complete picture of PSU performance, but discussions in the SPCR forums have convinced me that there are far too many variables at play to make internal PSU temperature a reliable gauge of... anything. There are way too many ways to interpret the numbers. Check this thread for the full discussion. The most critical parameter for thermal performance is efficiency. If efficiency is high, the size of the heatsinks and vent openings large, and the fan can blow a lot of air at full power, then excellent cooling is ensured.

Noise Measurements

The Heath AD-1308 is a portable half-octave Real Time Spectrum Analyzer with sound level meter (SLM) functions. Below 40 dBA, its accuracy is poor, limited to 3 dB increments, down to 23 dBA. Some 15 years old, this LED-based unit has long since been displaced by digital devices with better interfaces to PCs. The "A" weighting was used; it most closely approximates the frequency response characteristics of human hearing.

The microphone on the sound meter is positioned about a centimeter to the side of the PSU fan exhaust to avoid fan turbulence in the microphone itself. The dBA obtained here cannot be compared to any other measurements due to the lack of adherence to a repeatable standard and the uncontrolled reflective environment.

The noise measurements are always accompanied by descriptions of subjective perceptions. Without these, the measurements, which are not that reliable, provide only part of the picture.

TEST RESULTS

Measurements were made at 4 power levels: 90W, 150W, 300W and full power. The unit was allowed to run for at least 10 minutes at each power level before measurements were taken. The room temperature was 20C.

LOAD
90W
VR
150W
VR
300W
VR
550W
VR
+5V
20
1%
40
1%
80
1%
180
1%
+12V
36
1%
60
1%
144
1%
240
1%
-12V
3.6
1%
4.8
1%
4.8
1%
10
1%
+3.3V
26.4
1%
39
1%
65
1%
99
1%
-5V
2
1%
2
1%
2
1%
6
1%
+5VSR
2
1%
4
1%
4
1%
8
1%
AC Power
140W
216W
400W
770W
Efficiency
64.3%
69.4%
75.0%
71.4%
V Fan
5V
5.65V
7V
10V
Noise (~1 cm)
46 dBA
48 dBA
50 dBA
67 dBA
Case Temp
30C
31C
31C
33C

VR = With the feedback self-adjusting mechanism built into this PSU, I expected voltage regulation to be dead-on at all times. I adjusted the manual front panel controls once for perfect voltage at the 150W power level, then left them alone. The range of adjustment is about 0.5V, certainly more than adequate for this type of fine tuning feature.

At almost all loads, on all lines, the voltage regulation was just about perfect. At full power, I measured drops of 0.07-0.08V on all the lines; it was probably the effect of contact resistance within the DBS-2100 load tester itself, as it was consistent on all the lines, and I was using the contact points on the load tester, which come in the circuit after the PSU cables and connectors. Now, this is something of a static test in that none of the loads were actually bouncing up and down as they would be in a real life PC application (although what could possibly draw this much power...), but it is nevertheless, a very impressive performance.

Efficiency is best in the middle and higher power levels. The 64% efficiency rate at 90W is a bit low, but the PSU may be optimized for operation at higher power output, which only seems logical. The 75% calculated at the 300W output level is the best of all PSU units tested thus far by a couple of percentage points. Even at full power, it stayed above 70%.

V Fan: The voltage to the fan started at 5V and climbed in a more or less exponential curve to 10V at maximum power. The maximum fan voltage available is 11V, as I found by turning the manual fan speed to full. The fact that it hi only 10V suggests the PSU needed to get a bit hotter before the full cooling power of the fans is needed.

Noise was measured ~1 cm from the edge of the PSU fan exhaust, not in the airflow path. At all power levels ~100W or lower, fan voltage remained at the minimum of 5V. Measured to be 46 dBA, it is fairly quiet, considerably quieter than all other 2-fan PSU examined. The others, Enermax and Super Power models, all speeded up within 5 minutes of turn on even with hardly any load. It has no high pitched element; it is all middle and lower frequency noise, and air turbulence. No coil noise could be detected even with the fans forced off (by jamming them with elastic cord) at the 90W and 150W output level.

The noise level at 150W is only marginally higher than at 90W. At the 7V (300W level) the noise is significantly higher, and at full power, it is a veritable hurricane. The fan voltage and noise at the >150W level will be higher in a real PC than in our simulation. If you do manage to draw full power from this PSU, chances are you will not be too concerned about how noisy it is; effective cooling will be the primary concern.

Case Temp only rose by 3C between 90W and 550W, which suggests the PSU fan control does a pretty good job of keeping itself cool. Again, the temperature rise would be higher if the light bulb wattage was changed to match the output power at all times.

CONCLUSIONS

The Antec TrueControl 550 is a perfect PSU for a overclocker obsessed with control and a need for very high power. It has every control and monitoring tool you can think of. Its fundamentals, stable power delivery with tight regulation, are excellent. I have not done enough PSU testing with the new test rig to know whether this level of voltage regulation is common, but I would have to guess that it is not. Finally, it has the ability to deliver huge amounts of power.

But is it a good choice for a quiet computing enthusiast?

Probably only if you have this kind of power need. The TrueControl 550 is louder than any recommended single-fan PSU, or any tested thus far. While it is only moderately noisy at nominal power levels, the noise does ramp up at higher power. The truth is, there is no way you can have a quiet computer if your system usually requires much more than ~150W, regardless of PSU. They all require faster RPM fans at this kind of output to keep themselves cool enough, and that faster fan speed translates to higher noise.

For a quiet system with high power headroom requirements, but low average power consumption, it might be worthwhile to remove one of the existing fans and replace the other with a super quiet alternative. The two additional fan-only outputs go a long way to easing the construction of a noise-reduced high power PC: this feature is really clever. But at the MSP of US$160, the TrueControl 550 is not an inexpensive proposition. Surely Antec will also release lower power versions of the TrueControl.

While not a very quiet computing solution, but rather, a reduced-noise one, the TrueControl 550 offers unique control features and rock solid high power delivery. If you need such power, there seems little need to look further. Recommended.

Much thanks to Antec for the review samples and their kind support.

* * * * *

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