Tagan EasyCon XL 700W: A Tagan at Last

We’ve been anxious to get our hands on a Tagan for some time now, as our forum members have often commented that they have the potential to challenge for the silent crown. We got one at last, and it’s a high end doozy: 700W, modular cables, dual transformers… what more could we want? Well, there’s always low noise… Can we count on Tagan’s reputation?

January 10, 2007 by Devon
Cooke

Tagan’s reputation for quiet power supplies has been slowly expanding for years.
We get asked about them every so often, but, because we’ve never had a chance
to examine one first hand, we’ve never been able to say much on the subject.

That’s about to change, since we’ve finally managed to get our hands on one:
A 700W EasyCon XL with detachable cables, dual 12V transformers, and a US$200
price tag. The EasyCon XL is one of seven different model lines that
Tagan maintains, and we are assured by Tagan’s marketing department that it
contains the latest and greatest technology — which is all well and good,
but it doesn’t really tell us what we want to know most: Is it quiet?

At 700W, it’s almost a given that it won’t be quiet at full load, but it does
have several things going for it, including a high efficiency rating, a large,
135mm cooling fan, and a wider than usual mesh on the back panel. And, of course,
it has Tagan’s as yet untested (by SPCR) reputation behind it.

There’s only one market where a power supply this large and this expensive
has any hope of succeeding: The gaming market. As such, the EasyCon XL comes
with a healthy dose of bling to go along with its technical prowess. Foremost
among the extras: A sturdy “Easy Access Box” with two drawers —
one for spare cables and one for the power supply itself. The box is quite impressive,
if a little absurd. Why does a part that will spend its time installed in the
back of a computer case require its own carrying case? Most users will probably
want to repurpose the box for something else — screws and spare cables
anyone?

The retail package looks like it could hold tools — or jewelry…

…but in fact it’s just a very fancy way of packaging a US$200 power
supply.

Other extras include velcro cable ties, a grounding cable (?) and EMI shielded
cables for the VGA cards and the main AC power cable (another ?).

FEATURE HIGHLIGHTS

SPECIFICATIONS

Those who like to track OEM manufacturers (as opposed to retail brands) will
be interested to know that the UL number (E223995) for the EasyCon XL is actually
owned by Tagan, which suggests that Tagan had more than the usual cursory involvement
in the design of the unit.

As you would expect of a 700W power supply, power is plentiful on all of the
major lines, with all four +12V rails boasting peak capacities of 20A and a
combined maximum of 56A in total.

As always, it is wise to take these ratings with a grain of salt — all
the more so because of a design quirk that Tagan mentions in passing but doesn’t
really explain. The first page of the
PDF Datasheet for the EasyCon XL refers to “Dual Transformer Technology”.
The transformer is akin to the heart of the power supply, and having two means
that, speaking loosely, the EasyCon XL actually contains two power supplies:
One that powers +3.3V, +12V1 and +12V3, and another that powers +5V, +12V2 and
+12V4.

Dual transformers make it easier to meet a 700W output capacity, but do they
benefit the end user?

The practical benefit of this arrangement is that components powered by different
transformers are electrically isolated from each other. In theory, this could
lead to a more stable system, especially when overclocking, as isolated components
will not have to cope with the electrical noise that other parts produce, allowing
them to be pushed further before they become unstable.

However, it’s not clear whether this is actually the case in practice. Separate
components are rarely isolated within the system anyway, and a common path on
the motherboard between different components is enough eliminate the electrical
isolation that comes from having multiple transformers.

In reality, the dual transformers are probably there because they make it easier
to design a 700W power supply without overloading the transformer, not because
of any advantage to the end user.

EXTERNAL TOUR

The appearance is fairly unremarkable. The matte black finish is pretty much
par for the high end course, but there’s no sign of shiny titanium or glowing
LED lights. There are a few places where Tagan has branded their logo onto the
casing, but that’s pretty much where the visual adornments stop.

Note the extremely open rear grill.

There are a couple of minor design quirks that set the EasyCon XL apart from
other power supplies. One is the length: At 175mm long, it complies with the
recommended length for EPS12V power supplies in its capacity level. The only
problem is that some cases are only designed to fit the 140mm length that is
standard for ATX12V units. You’ll want to double-check that your case has room
for a longer power supply — and don’t forget that the detachable cables
add about three centimeters to the total length.

Venting along the side of the casing keeps hot components cool.

The other unusual aspect of the exterior is a long vent that runs down one
side of the power supply. Presumably, there are hot components here that would
otherwise be improperly cooled. However, the position of these vents is a little
strange, as there’s not always a lot of space for airflow between the power
supply and the side panel.

CABLES AND CONNECTORS

There are a total of fourteen cable sets (wow), all of which are sleeved in
either black vinyl or copper EMI shielding:

• 18″ cable for main 20+4-pin ATX connector — sleeved in black vinyl
• 18″ cable for 4+4-pin AUX12V connector — sleeved in black vinyl
• 18″ ground wire
• 2 x 21″ cables for 6-pin PCIe connector — with a ferrite ring
  and sleeved in copper mesh
• 2 x 23″ cables with two 4-pin IDE drive connectors — sleeved in
  black vinyl
• 1 x 18″ cable with two 4-pin IDE drive connectors — sleeved in
  black vinyl
• 1 x 21″ cable with one 4-pin IDE drive connector — with a ferrite
  ring and sleeved in copper mesh
• 2 x 23″ cables with two SATA drive connectors — sleeved in black
  vinyl
• 2 x 18″ cables with two SATA drive connectors — sleeved in black
  vinyl
• 1 x Molex to 2 x Floppy adapter with one 6″ cable and one 10″
  cable

Overall, we were a bit surprised at how short the cables seemed to be, the
main motherboard and AUX cables in particular. 18″ is not long enough for
some high end cases (for example, Antec’s P180), especially those with unusual
layouts. We also found the cables very stiff and hard to manage, especially
the cables with copper sleeving.

Aside from the main motherboard headers, the +12V AUX connector, and the mysterious
ground wire, all of the cables are modular and need only be installed when necessary.

Unusual modular connections that appear to be modified PCIe plugs.

The modular connectors are large and easy to grip, and they mate snugly and
securely. In fact, they’re a little too snug: The photo below shows what can
happen if you pull a little too enthusiastically when you’re disconnecting the
cables…

The modular sockets can be pulled out by accident.

The two PCI Express cables are color coded and use slightly different plugs
from the rest of the cables, making it impossible to accidentally plug the cables
in wrongly.

INTERIOR

The cover pops off to reveal a densely packed PCB with the promised twin transformers
in the middle flanked by two black anodized heatsinks. There’s not a lot of
space for airflow between the various components, and it’s easy to believe that
heat buildup could be a problem without the side vent shown on the previous
page.

Twin transformers in the center.

Although the rear grill is very open, a significant portion of it is blocked
by a secondary PCB (probably the PFC circuit) that rises vertically just behind
the power socket.

Cable sets are neatly organized and isolated from each other with heat
shrink.

The heatsinks are chunky enough, and numerous fins provide plenty of surface
area. Our only concern is fin density: The fins are packed tightly and there
is little room for air to escape. A low speed fan may not provide enough pressure
to force air through the power supply.

Densely packed heatsinks.

A small secondary heatsink provides additional cooling.

FAN

Tagan branded, but the model number shows up in Globe Fan’s database.

The EasyCon XL is one of a few recent power supplies to use a fan larger than
the usual 120mm (or 80mm) size. Its 135mm fan is about as large as it is possible
to fit within the confines of a power supply.

The fan is branded with Tagan’s logo, but a search for the model number revealed
that the
fan is manufactured by Globe Fan. It uses ball bearings, and is rated for
a noisy 2200 RPM and 46.2 dBA. There’s not much hope that it will be quiet at
higher speeds, but perhaps the starting voltage will be low enough to keep it
quiet when it starts.

TESTING

For a fuller understanding of ATX power supplies, please read the reference
article Power Supply Fundamentals & Recommended
Units. 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
V.4. The testing system is a close simulation of a moderate airflow
mid-tower PC optimized for low noise.

In the 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 (~6-7V) 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 our testing loads 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 65W and 250W, 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 maximum power draw that an actual
system can draw under worst-case conditions. Our most power-hungry
Intel 670 (P4-3.8) processor rig with nVidia 6800GT video card drew ~214W DC
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 video card
today could draw as much as another 60~100W, but the total still remains well
under 400W in extrapolations of our real world measurements. As for high end
dual video card gaming rigs… well, to be realistic, they have no place in
silent computing today.

SPCR’s high fidelity sound
recording system was used to create MP3 sound files of this PSU. As
with the setup for recording fans, the position of the mic was 3″ from the exhaust
vent at a 45° angle, outside the airflow turbulence area. The photo below shows
the setup (a different PSU is being recorded). All other noise sources in the
room were turned off while making the sound recordings.

INTERPRETING TEMPERATURE DATA

It important to keep in mind that fan speed varies with temperature,
not output load. A power supply generates more heat as output increases, but
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:

• Intake temperature (determined by ambient temperature and power output level)
• Efficiency of the PSU (how much heat it generates while producing the required
  output)
• The effectiveness of the PSU’s cooling system, which is comprised of:
  • Overall mechanical and airflow design
  • Size, shape and overall surface area of heatsinks
  • Fan(s) and fan speed control circuit

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

Ambient conditions during testing were 21°C and 19 dBA. AC input was 122V,
60Hz. Note that our testing equipment is set up to accommodate only two +12V
rails, and the +12V1 and +12V2 columns in the data table below refer to the
loads as measured on our test bench. In addition, it’s far from clear which
rails power which connections. For this reason, the exact load balance across
the various +12V rails is unknown.

ANALYSIS

1. EFFICIENCY was good, but it didn’t live up to the expectations that
we have of a power supply that appears
to be 80-Plus certified. If fact, it’s peak efficiency barely broke 80%
— a long way from the 84% peak efficiency that was measured in the 80-Plus
report.

Efficiency at lower loads was actually quite poor, perhaps because the second
transformer added some power overhead that most power supplies don’t have to
deal with (see low-load performance below).

We can only speculate why our test sample did not meet expectations, but there
are three possibilities that come to mind:

1. The sample tested in the 80-Plus test was a special 80-Plus version that
   will be released in addition to the regular version. This would explain why
   Tagan does not list 80-Plus compliance anywhere in their marketing material.
2. Our stringent thermal test conditions caused efficiency to drop (especially
   at full load). 80-Plus tests are conducted in a uniform thermal environment,
   regardless of load.
3. It’s possible that our test did a poor job of balancing the load between
   the two transformers, leading to one or the other being loaded above or below
   the optimal point on its efficiency curve. As a result, the total efficiency
   would end up being lower, as the two transformers would hit their peaks at
   different times instead of simultaneously.

2. VOLTAGE REGULATION was probably the best we’ve ever seen. All voltage
lines remained within ±3% of nominal (+12V and +5V were within 2%), but
what was really impressive was how little fluctuation there was. The
largest fluctuation was ~1.1% on the +5V line, with a high of 5.09V @ 65W to
a low of 5.03V @ 600W. All other lines were regulated to within 1%.

3. RIPPLE

Ripple was far below the tolerance limits of 120 mV (+12V) and 50 mV (+3.3V
& +5V), even under stressful conditions. Even in the worst cases, ripple
never exceeded about a quarter of the maximum limit.

This bizarrely irregular waveform was produced on the +12V line at 200W output.

4. POWER FACTOR was excellent thanks to the active power factor correction
circuit, staying very close to the theoretical maximum of 1.0.

5. LOW LOAD PERFORMANCE

There’s no question that the EasyCon XL is a beefy power supply, so it’s probably
a little unfair to fault it for poor low load performance, but we’re going to
do so anyway. The 15W consumed with no load on the power supply was almost double
what other power supplies have achieved, and it probably contributed to the
poor low-end efficiency.

6. LOW AC VOLTAGE PERFORMANCE

Doing the low AC voltage test with 700W flowing through the system was an exciting
experience, punctuated by occasional sparks and flashes from within the bright
orange variac that we used to reduce the voltage. Despite these signs that we
were playing with powerful forces beyond our control (wheeee!), the Tagan handled
the fluctuation like a champ. The only visible change on the output side was
a slight increase (<1 mV) in +12V ripple.

7. TEMPERATURE & COOLING

The thermal performance of the EasyCon XL was somewhat questionable. Thermal
performance under heavy load was quite poor, and the output temperature reached
a scorching 72°C at full load.

Even at more reasonable loads in the 200~400W range, the thermal rise through
the unit was in the 10~20°C range, which is too much for a unit that is
operating at 80% efficiency.

About the best we can say for the thermals is that it didn’t seem to affect
electrical performance very much. Yes, the high end efficiency did drop a bit,
but no other signs of overheating ever appeared — AC power consumption
was stable, output voltages didn’t move, and ripple didn’t increase any more
than expected.

8. FAN, FAN CONTROLLER and NOISE

It’s a shame to save the worst for last, but it’s hard to call the noise produced
by the EasyCon XL anything else. A baseline noise level of 29 dBA@1m is simply
too loud to consider for a quiet computer, and that’s really all there is to
be said.

I could go on to comment on the noise character (resonant), fan controller
(too active), or point out that the starting voltage is too high, but there’s
little point in considering these fine details when it won’t be quiet under
any circumstances. Even a fan swap is made difficult by the unusual dimensions
of the fan. For once, the measure noise level tells you everything you need
to know about how the EasyCon XL sounds.

MP3 SOUND RECORDINGS

Each of these recording have 10 seconds of silence to let you hear the ambient
sound of the room, followed by 10 seconds of the product’s noise.

• Tagan EasyCon XL 700W at 40W, 29 dBA@1m: One
  meter, One
  foot (30cm)

• Seasonic S12-430 at 0~90W, 20 dBA@1m: One
  meter, One
  foot (30cm)
• Antec NeoHE 430 at 0~90W, 20 dBA@1m: One
  meter, One
  foot (30cm)
• Corsair HX500 & 600W at 0~300W, 22 dBA@1m: One
  meter, One
  foot (30cm)
• Silverstone Element Plus ST50EF-Plus at 0~200W, 23 dBA@1m:
  One meter,
  One foot (30cm)

CONCLUSIONS

It’s too bad that Tagan’s reputation for quiet doesn’t seem to extend to this
model, because the electronics inside the EasyCon XL are quite good. The dual
transformer design has its advantages, one of which is exceptionally stable
voltage rails, as seen here. This is enough to forgive the questionable thermal
performance (since the hot conditions didn’t appear to affect anything), but
it’s not enough to forgive poor noise.

The EasyCon XL has a lot to offer the enthusiast market, and, despite stiff
cables and connectors, we have to admit that the spit and polish on the detachable
cables is quite impressive. Although it is functionally no different from any
other modular power supply, it somehow “feels” more finished, and,
in the high end market, “feel” is often as important as raw performance.

It will be interesting to watch what happens to this model line in the future.
140mm fans suddenly seem to be all the rage, and it’s quite possible that they
will become dominant, just as 120mm fans supplanted 80mm fans a few years ago.
If that occurs, perhaps Tagan will be able to source a quieter fan for the next
revision of the EasyCon XL.

*

SPCR Articles of Related Interest:
Power Supply Fundamentals & Recommended
Units
Power Distribution within Six PCs
Corsair HX520W & HX620W Modular Power
Supplies
Seasonic Goes High End Gaming with the M12
Antec NeoHE 430
Silverstone Element Plus ST50EF-Plus

* * *

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