Antec TruePower New TP-750

The TruePower series has been bread-and-butter for Antec for many years, but the line has recently received a refresh. Partly modular cabling, high efficiency, lower noise, and high quality parts are all promised in these new Seasonic-made models. How do they fare against the SPCR short list?

The TruePower series has been one of Antec’s bread-and-butter power supply
lines for many years. Naturally, it has evolved continuously since its inception.
The current iteration has a combination of attached and detached cables, in
four models ranging 550W to 750W, Japanese brand capacitors for reliability,
DC to DC converters for exceptional voltage regulation, a Japanese brand 120mm
PWM fan for quiet operation and 80 PLUS® Bronze certification for greater
efficiency. These are impressive features for PSUs selling on the street for
just $90~120.

Antec has been a major brand in power supplies for a couple of decades now.
It is still one of the best-distributed case and power supply brands in the
business. The California-based company has had many power supply partners over
the years, including Channel-Well, Enhance, Delta and Seasonic. It offers an
enormous range of power supplies, something like over 30 models in 8 lines.
The True Power line is now made by Seasonic, a manufacturer that has moved steadily
up to the forefront of PSU technology and consumer awareness in recent years.
The partnership between Seasonic and Antec goes back to 2005. To differentiate
the current TP series from previous ones (which were made by Channel-well, we
believe), the word "New" has been added to the name, as in TruePower
New; this generic appellation seems destined for instant obsolescence.

PACKAGING & FEATURES

The packaging of the TruePower New series is considerably more minimalist than
most other brand-name retail PSUs. This is a good thing, ecologically speaking.

The TP New series have retailer-friendly but still minimalist packaging, which we applaud. Inside, the green theme continues: Recycled cardboard and paper takes the place of styrofoam. About the worst thing in the packaging are the plastic bags, one of which is used to hold the detachable output cables. This is still way more eco-friendly than most electronics or computer packaging.

The multiple 12V lines means that there is a current limiter on
each one, but the juice all comes from the same 12V source. A 750W power supply
is plenty for even a very serious gaming PC. None of the output lines are likely
to come anywhere near their rated maximum during ordinary use.

VISUAL TOUR

Visually, it is a standard 120mm fan power supply. The finish for the TP-750
is flat black, all around. The only relief from the black comes in the cables,
output connectors and the label. All the cables, attached and detached, are
sleeved.

Flat black only, no adornments. The red ouput connectors and the purple on the label break up the monotony. Label boasts all the certifications. The modular and AC cables.

OUTPUT CABLES

All the cables are nicely sleeved for a clean tidy look. There are more permanently
attached output cables than detachable ones, which kind of undermines the whole
idea of detachable cables. In fact, there are enough attached output cables
for most PCs. So think of it as a conventional PSU that has the option to add
more cables if you need them.

Attached

• 1 – 24P MainBoard (main ATX) – 21"
• 1 – 8P CPU (EPS 12V) – 25"
• 1 – 4P CPU (12VAUX) – 21"
• 2 – 6P + 2P PCIE 21"
• 1 – 3x SATA 33"
• 1 – 3x Molex + 1 floppy 39"

Modular

• 2 – 3x Molex + 1 floppy 39"
• 2 – 3x SATA 33"
• 2 – 6P PCIE 21"

INSIDE

The predominately black coloring continues on the inside. Even the heatsinks
are anodized black. There’s little question of the TP-750’s origins; everything
from the coils to the capacitors, the transformers, and the heatsinks have that
familiar Seasonic look.

TESTING

For a fuller understanding of ATX power supplies, please read
the reference article Power
Supply Fundamentals. Those who seek source materials
can find Intel’s various PSU design guides at Form
Factors.

For a complete rundown of testing equipment and procedures, please
refer to SPCR’s
PSU Test Platform V4.1. The testing system is a close simulation of
a moderate airflow mid-tower PC optimized for low noise.

Acoustic measurements are now performed in our anechoic chamber with ambient level of 11 dBA or lower, with a PC-based spectrum analyzer comprised of SpectraPLUS software with ACO Pacific microphone and M-Audio digital audio interfaces.

In our test rig, the ambient temperature of the PSU varies proportionately
with its output load, which is exactly the way it is in a real PC environment.
But there is the added benefit of a high power load tester which allows incremental
load testing all the way to full power for any non-industrial PC power supply.
Both fan noise and voltage are measured at various standard loads. It is, in
general, a very demanding test, as the operating ambient temperature of the
PSU often reaches >40°C at full power. This is impossible to achieve
with an open test bench setup.

The 120mm fan responsible for "case airflow" is deliberately
run at a steady low level (7V) when the system is run at "low" loads.
When the test loads become greater, the 120mm fan is turned up to a higher speed,
but one that doesn’t affect the noise level of the overall system. Anyone who
is running a system that draws 400W or more would definitely want more than
20CFM of airflow through their case, and at this point, the noise level of the
exhaust fan is typically not the greatest concern.

Great effort has been made to devise as realistic
an operating environment for the PSU as possible, but the thermal and noise
results obtained here still cannot be considered absolute. There are too many
variables in PCs and too many possible combinations of components for any single
test environment to provide infallible results. And there is always the bugaboo
of sample variance. These results are akin to a resume, a few detailed photographs,
and some short sound bites of someone you’ve never met. You’ll probably get
a pretty good overall representation, but it is not quite the same as an extended
meeting in person.

REAL SYSTEM POWER NEEDS: While we test the PSU to full
output in order to verify the manufacturer’s claims, real desktop PCs simply
do not require anywhere near this level of power. The most pertinent range of
DC output power is between about 40W and 300W, because it is the power range
where most systems will be working most of the time. To illustrate this point,
we
conducted system tests to measure the power draw of several actual systems
under idle and worst-case conditions. Our most power-hungry overclocked
130W TDP processor rig with an ATI Radeon X1950XTX-512 graphics card drew ~256W
DC peak from the power supply under full load — well within the capabilities
of any modern power supply. Please follow the link provided above to see the
details. It is true that very elaborate systems with the most power hungry dual
video cards today might draw as much as another 150~200W, but the total should
remain under 500W in extrapolations of our real world measurements.

INTERPRETING TEMPERATURE DATA

It important to keep in mind that PSU fan speed varies with temperature,
not output load. A power supply generates more heat as output increases, but
this is not the only the only factor that affects fan speed. Ambient temperature
and case airflow have almost as much effect. Our test rig represents a challenging
thermal situation for a power supply: A large portion of the heat generated
inside the case must be exhausted through the power supply, which causes a corresponding
increase in fan speed.

When examining thermal data, the most important indicator of cooling
efficiency is the difference between intake and exhaust. Because
the heat generated in the PSU loader by the output of the PSU is always the
same for a given power level, the intake temperature should be roughly the same
between different tests. The only external variable is the ambient room temperature.
The temperature of the exhaust air from the PSU is affected by several factors:

The thermal rise in the power supply is really the
only indicator we have about all of the above. This is why the intake temperature
is important: It represents the ambient temperature around the power supply
itself. Subtracting the intake temperature from the exhaust temperature gives
a reasonable gauge of the effectiveness of the power supply’s cooling system.
This is the only temperature number that is comparable between different reviews,
as it is unaffected by the ambient temperature.

TEST RESULTS

The ambient temperature was 22~23°C, and the ambient noise
level was 10~11 dBA. AC input voltage was 118~121V.

1. EFFICIENCY — This is a measure of AC-to-DC conversion
efficiency. The ATX12V Power Supply Design Guide recommends 80% efficiency or
better at all output power loads. 80% efficiency means that to deliver 80W DC
output, a PSU draws 100W AC input, and 20W is lost as heat within the PSU. Higher
efficiency is preferred for reduced energy consumption and cooler operation.
It allows reduced cooling airflow, which translates to lower noise. The 80 Plus
Bronze standard requires a minimum of 82% efficiency at 20% load, 82% efficiency
at 50% load, and 82% efficiency at full rated maximum load.

Our samples met 80 Plus Bronze requirements. 80% efficiency was
reached at a modest ~75W; by 90W, it was at 82.2%. A broad peak of 84~86% efficiency
was maintained from about 150W to 500W load. Beyond that, it drooped a bit as
expected, down to 80.2% at maximum load.

2. DC VOLTAGE REGULATION refers to how stable the output
voltages are under various load conditions. The ATX12V Power Supply Design Guide
calls for the +12, +5V and +3.3V lines to be maintained within ±5%.

Unless a unit goes into overload, it’s rare that we see significant
problems with voltage regulation with the higher quality PSUs SPCR generally
examines. The TP-750 was excellent, better than ±2% on any line under
all loads.

3. AC RIPPLE refers to unwanted "noise"
artifacts in the DC output of a switching power supply. It’s usually very high
in frequency (in the order of 100s of kHz). The peak-to-peak value is measured.
The ATX12V Guide allows up to 120mV (peak-to-peak) of AC ripple on the +12V
line and 50mV on the +5V and +3.3V lines. Where voltage regulation is a measure
of variance from spec, ripple is more a measure of tolerance: How much the voltage
is changing at any given time. Ripple is of interest to over- and under-clockers
who push their systems to the limits of what they are actually capable
of rather than relying on what the specs say they should be capable of.

Ripple on the 12V line was a bit higher than we’ve seen in other
recent PSUs, but still well within spec at <70mV even at full load. More
typically it was 20~40mV. The 5V and 3.3V lines also were within spec, with
under 40mV ripple & noise at all levels.

4. POWER FACTOR is ideal when it measures 1.0. In the most
practical sense, PF is a measure of how "difficult" it is for the
electric utility to deliver the AC power into your power supply. High PF reduces
the AC current draw, which reduces stress on the electric wiring in your home
(and elsewhere up the line). It also means you can do with a smaller, cheaper
UPS backup; they are priced according to their VA (volt-ampere) rating.

As is the case for most units with active power factor correction
(which, these days, is most reputable brands), PFC was close to perfect, starting
at 0.93 for the minuscule 20W load, and staying at 0.99 through most of the
operating range.

5. LOW LOAD TESTING revealed no problems starting at very
low loads and it stayed operational with no load applied. As advertised, the
power draw in the off (standby mode) was under 1W. It also started without a
load, with a very low 4.3W AC power draw.

6. LOW & 240 VAC PERFORMANCE

The power supply was set to 500W load with 120VAC through the
hefty variac in the lab. The variac was then dialed 10V lower every 5 minutes.
This is to check the stability of the PSU under brownout conditions where the
AC line voltage drops from the 120V norm. Most full-range input power supplies
achieve higher efficiency with higher AC input voltage. SPCR’s lab is equipped
with a 240VAC line, which was used to check power supply efficiency for the
benefit of those who live in 240VAC mains regions.

Efficiency improved a little over 3% with 245VAC input at this
load. The sample passed the 100VAC minimum input without any issues. Neither
voltage regulation nor ripple changed appreciably during the test.

7. TEMPERATURE & COOLING

The TP-750 kept temperature rise to well under 10°C until
nearly 500W load. At full load, the temperature rise was still a modest 17°C.
This is excellent cooling. As with all quiet PSUs, don’t count on the TP-750
to remove much heat from your system; make sure the cases fans do their job.

7. FAN, FAN CONTROLLER and NOISE

The fan controller does a nice job of balancing noise with cooling.
The RPM was not closely monitored, but judging from the SPL measurements, the
fan controller has a good number of speed levels from minimum to maximum.

At minimum load , the fan spins at somewhere a bit below 400 RPM,
according to our calibrated strobe. This is similar to the fan in the Enermax
Modu/Pro87+ 500, which measured a hair lower, both in SPL and RPM. The noise
level of the TP-750 is low enough up to ~200W load to be a non-factor in almost
any PC with other moving parts. It’s difficult to hear even from very close
up. Even up to somewhere over 300W, it is still quiet enough that other cooling
fans (such as the one for the video card) are probably going to making more
noise — given the cooling needed for the components if they are demanding
that much power. By 400W, the noise is plainly audible, but this is hardly unusual
or unexpected. If such power is being delivered to them. other components in
most systems will be screaming for cooling airflow, too.

The quality of the noise is moot until beyond 300W when it becomes
more obvious. There is some electronic buzzing and humming, but these sounds
are audible only from very close up. The fan noise is quite smooth, mostly broadband
with minimal tonal elements. Overall, it’s a relatively benign noise until >300W
load is reached.

12 dBA@1m at under 200W. There’s very little difference between the ambient (red line) and when the PSU is on. A bit of very high pitched electronic whine can be seen at ~15kHz; this was at too low a level to be audible. The overall sound was a muted whispering , as if two sheets of paper were being softly rubbed together. 14 dBA@1m at 200W. The fan noise is clearly visible, mostly concentrated between 150 and 700 Hz. There’s a touch of hum around 200 Hz. Above 1,000 Hz, there is virtually no noise. 18 dBA@1m at 300W. Most of the noise is between 100 Hz and 1.5 kHz. There’s very little tonality and no high frequency noise.

Noise in a Cooler Case

One thing we’ve been examining is how the power supply performs
outside the tough thermal conditions of our standard test. The
recent popularity of cases that isolate the power supply from the rest of the
system make this a relevant question, as the cooler intake air allows the fan
to run slower and quieter. We examine this by running some of the high load
tests with the power supply in free air, away from the tough thermal conditions
of the hot-box.

Outside the hotbox, the fan’s increase in speed occurred at a
higher power level, and its rate of increase was lower. This suggests that in
a case with isolated external intake vent for the PSU, the TP-750 would remain
inaudible to well over 300W load. This actually covers the vast majority of
PCs, including DIY gaming rigs.

COMPARISONS

The comparison table below shows the SPL versus Power Load data on all the
PSUs tested in the anechoic chamber thus far. It’s difficult to rank them, as
the measured SPL varies with power load. The units which are quietest at minimum
load are not always the quietest at midload (100W~300W), which may make them
louder in actual use. Then there’s the noise level at 400W and up, which will
determine the quietest PSUs for high power gaming rigs, during actual gaming.

The Antec TP-750 falls in the middle of the pack, which is pretty good because
it is in very quiet company. At the <200W power loads, the TP-750 stands
within a decible or two with the quietest PSUs around. In fact, it stands up
well even at 300W where it is much closer to the quietest of the bunch than
the noisiest. By 400W, it climbs beyond our 30 dBA@1m "too loud" mark,
but it’s hardly any different from such celebrated performers as the Seasonic
X-650 or the Antec Signature 650.

Caution: Please keep in mind that the data in the above table is specific to the conditions of our test setup. Change the cooling configuration, the ambient temperature and any number of other factors, and you could change the point at which the fans start speeding up, as well as the rate of the rise in speed. The baseline SPL is accurate, however, probably to within 1 dBA.

MP3 SOUND RECORDINGS

These recordings were made as 24-bit / 88 kHz WAV files with a high
resolution, lab quality, digital recording system inside SPCR’s
own anechoic chamber (11 dBA ambient), then converted to LAME 128kbps
encoded MP3s. We’ve listened long and hard to ensure there is no audible degradation
from the original WAV files to these MP3s. They represent a quick snapshot of
what we heard during the review.

These recordings are intended to give you an idea of how the product sounds
in actual use — one meter is a reasonable typical distance between a computer
or computer component and your ear. The recording contains stretches of ambient
noise that you can use to judge the relative loudness of the subject. Be aware
that very quiet subjects may not be audible — if we couldn’t hear it from
one meter, chances are we couldn’t record it either!

Each recording starts with 6~10 seconds of room ambient, followed
by 10 seconds of the product’s noise and various settings. For the most
realistic results, set the volume so that the starting ambient level is just
barely audible, then don’t change the volume setting again while comparing all
the sound files.Sound Recordings of PSU Comparatives in the Anechoic
Chamber

• Antec TP-750 at various loads in anechoic chamber at one meter
  — idle to >150W (12 dBA@1m)
  — 200W (14 dBA@1m)
  — 300W (18 dBA@1m)
  — 500W (33 dBA@1m)
  — 750W (40 dBA@1m)

Comparatives

• Enermax
  Modu/Pro87+ 500 at various loads in anechoic chamber at one meter
  — idle to >250W (11 dBA@1m)
  — 300W (14 dBA@1m)
  — 400W (20 dBA@1m)
  — 500W (23 dBA@1m)

• Seasonic
  X-650 at various loads in anechoic chamber at one meter
  — idle to >150W (ambient of chamber – 11 dBA@1m)
  — 200W (12 dBA@1m)
  — 250W (14 dBA@1m)
  — 300W (16 dBA@1m)
  — 400W (31 dBA@1m)

• Enermax
  Eco80+ at various loads in anechoic chamber at one meter
  — idle to >90W (11 dBA@1m)
  — 200W (16 dBA@1m)
  — 250W (19 dBA@1m)
  — 300W (26 dBA@1m)

CONCLUSIONS

It’s not easy to be a star power supply at SPCR these days. The
high struttin’ 80 Plus Gold models dominate the top, and only other goldies
can hope to join their ranks. The noise level has dropped literally into silence,
with Gold and fanless models making no noise at all. So what’s a middle class
boy like the Antec True Power 750 to do? The best he can, of course, and that
is pretty dang good even by the rarified PSU standards of SPCR in mid-2010

The noise level of the TP-750 from minimum load to over 150W is
about as quiet as any fan-cooled PSU can be. It measured a hair above the Enermax
Modu/Pro87+ 500W, which was essentially at the ambient level of the anechoic
chamber, but you’re not likely to hear either one in any normal setting. The
difference between the TP-750 and the Modu/Pro87 500W is that the latter has
a shallower fan-speed-to-load curve, which means it stays quieter to a higher
load. This is patently unfair comparison, because the Enermax is a much pricier
80 Plus Gold model in that brand’s premier line… and it almost impossible
to find in the marketplace at any price these days. The TP-750 is very widely
distributed and almost cheerfully affordable in comparison. Use it in an advanced
computer case that provides access to outside air for the PSU, and the TP-750
will easily stay very quiet to over 300W load.

Electrically, the TP-750 does an excellent job on every measurable
parameter. Somewhat higher ripple and noise at full power could be quibbled
about, but it is still well within specifications. It also keeps itself very
well cooled, despite the low fan speed at lower power loads.

Perhaps most welcome of all is the fact that the TP-750 is one
of a family which extends downward to the TP-650 and TP-550. The lower power
models can surely be expected to provide the same acoustic and electrical performance
at <300W, which is the main power range of concern to the vast majority of
DIY PC builders.

Much thanks to Antec
for the review samples.

The Antec TruePower New TP-750 is Recommended by SPCR.

* * *

SPCR Articles of Related Interest:
Power Supply Fundamentals

Recommended Power Supplies
SPCR PSU Test Rig V.4
Seasonic X-400 Fanless
Seasonic X-650: Seasonic Hits
Gold
Enermax Modu/Pro87+ 500W
Antec CP-850: Unique PSU with Top Performance
Nexus NX-5000 Silent PSU

* * *

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