Product Review -
LLano Design Group SA-3 Monoblock Amplifiers - March, 1997
By John E. Johnson, Jr.
Click to see larger photo |
LLano Design Group SA-3 Monoblock Power
Amplifier; Class A/B; 750 watts rms per monoblock into 8 Ohms
(100 watts class A), 1,500 watts rms into 4 Ohms; Bandwidth
response DC - 100 kHz -3dB; THD < 0.1% @ 1 kHz; Slew rate 80
V/µsec; Input impedance 47 kOhm unbalanced (RCA), 600 Ohm
balanced (XLR); Output impedance 0.05 Ohm; Size 7"H x
19"W x 14"D; Weight 45 pounds each; Black metal
chassis; $3,995/pair; LLano Design Group; 4804 84th Street,
Lubbock, Texas 79424; Phone 806-794-4879; E-Mail [email protected]; Web Site http://www.LLanodesign.com.
When Randy White, originally of White Audio, called me to say
that his company was now called LLano Design Group, and that he
had a new line of amplifiers, I jumped at the chance to get a
pair of his SA-3 monoblocks. The SA-3s are fully differential,
which means balanced throughout. The negative "pole" is
not connected to ground as it is in an unbalanced amplifier. This
results in an additional 3 dB of gain, less hum, and a different
sound altogether. LLano Design sells factory direct. In the
high-end market, the competition is tough because most of the
manufacturers make very good products. LLano decided that the
only way to compete here was to sell direct to the consumer,
which means that the price is reduced by about 40% compared to
products that you would find in dealer showrooms. Of course, this
has its drawbacks. You can't drop by your dealer and listen to
them. You have to buy them first, listen, keep them or send them
back. A pain . . . no ifs, ands, or buts. However, if you want to
save kilobucks (in the case of the SA-3s), its worth the chance.
The worst case scenario is that you pay $150 to ship them back to
LLano for a refund. Judging by the sound of these babies, I don't
think that will happen very often. My guess is, these would cost
about $6k/pair in shops.
One of the things you pay for with a high end amp is the looks.
You can't get this kind of power and sound quality in a cheap
box. No way. The SA-3s are gorgeous! The color (black) is not
unusual, but the brushed aircraft aluminum chassis is. The front
has a gold logo, on/off toggle, and a small blue LED to indicate
power on. Heat sink fins are often an indication of power, and
the SA-3s have BIG ones. They stick out quite a distance along
the sides, are thicker at the junction to the chassis than they
are out at the ends, and are lightly ribbed [click here for photo
of top]. This makes the fins more
efficient. The back has a three pronged AC power cord connector,
balanced/unbalanced switch, RCA and XLR input jacks, and two sets
of speaker binding posts (keep in mind each chassis is a single
mono amplifier). The binding posts are marked to indicate that
the negative post is not grounded. [Click here to see
photo of back of amplifier.]
Like all good amplifiers, the power supply takes up most of the
chassis inside. Two 40,000 µF capacitors (250 Joules of energy
storage in each monoblock) and a very large EI core transformer
occupy most of the space [click here to see photo of inside chassis]. Because this is a massively powered amp, the use
of two caps rather than multiple caps was chosen. This results in
more impulse power, which is a desirable characteristic when 750
watts may have to be delivered. Multiple caps (in certain cases,
called "distributed node") can sound better under
certain circumstances, but the intense impulse power capability
was selected as the priority here. (Multiple caps are used in
some of LLano's other amplifiers.) This brings up an interesting
point. Why would you ever need this kind of power? Well, the
perceived loudness increases by a factor of two when the power
(watts) increases by a factor of ten. So, 700 watts is only twice
as loud as 70! (The SPL in dB increases by a factor of 10 as
well, but the perceived loudness is doubled. So, if 70 watts
produces 80 dB of SPL, 700 watts will produce 90 dB and will
sound twice as loud. Doubling the watts from 70 to 140 produces
an increase of 3 dB, i.e., if 70 watts produces 80 dB, 140 watts
will produce 83 dB.) Secondly, transients can be very demanding,
such as the attack when a steel string guitar is plucked, or a
powerful piano note. The transient lasts only a short time -
perhaps a few milliseconds - yet, the ability of the amplifier to
reproduce those transients at the high level of the original, can
make the difference in sounding "real". The transients
demand about 20 times the average listening power, so if you are
listening at about 30 watts, and along comes a powerful
transient, 600 watts are needed to reproduce it. Just for an
instant, and then the music goes back to 30 watts. That instant
is very important. Thus the SA-3s. An EI core (regular iron core)
transformer was chosen over a toroidal because of its low noise
characteristics. Toroidals are used in many amp designs these
days because of their efficiency for their size. Space was not a
problem with these monoblocks (toroidals are used in LLano's
small amplifiers).
Only two stages of amplification are used in the SA-3s. In most
amps, there are at least three: the input stage where voltage
amplification takes place, the driver stage, and the output stage
where current delivering capability is established. LLano has
designed the SA-3s so that the input and driver stages are
combined into one stage. Simplifiying the circuitry means that
the signal passes through less parts, and that means better
sound. The irony is that it's difficult to design a great amp
with fewer parts.
Sixteen Hitachi MOSFET output devices are used in each monoblock.
This, coupled with the large power supply, provides massive
current available to the speakers, and a rating into very low
impedance loads. The amp is biased well into class A operation
(100 watts out of the 750). MOSFET amps work best when biased
into class A, but the amount of class A (fraction of total power)
varies. With the SA-3s, most of the time, you will be listening
to class A sound. The majority of other high-end, high power
amplifiers use bipolar output devices, so a MOSFET output stage
is a distinction in the SA-3s. Since MOSFETS deliver less current
when they heat up, lots of MOSFETS are required compared to
bipolars. Otherwise, the sound can fall apart when the amp is
cranked to its limits and warms up. The Hitachi MOSFETS used in
the SA-3s are very high powered (rating), and the amps barely got
warm when we listened for extended periods, and to loud music.
This is an indication that the output stage is overbuilt so
MOSFET limitations are never reached. THAT is high-end audio.
Speaking of sound, then, how do the SA-3s perform? In a word . .
. incredible! It is difficult to say what is the reason . . .
class A operation, differential design, extreme high power output
capability. Whatever. Probably a combination of all these
factors. I have never heard anything better than this. I have
listened to amps that sound as good (though all of them are more
expensive and have less power output capability), but nothing
that exceeded the SA-3s. Detail, impact, sound stage, musicality,
. . . it's all there. We put the amplifiers through some very
tough music, and no matter how loud we played them, there was no
audible harshness that would have otherwise indicated demand
beyond ability. The bass was perhaps most astonishing of all.
Bass requires massive power to punch it through. (We used the
amps with big ribbon speakers.) The low kettle drum notes made my
neck hairs stand on end. These amplifiers are something else!
Being able to crank up symphonic music until it sounded like the
orchestra was in the room was a wonderful experience. An
experience I don't want to let disappear. So, I'm not sending
these back. They stay!
In summary, I never thought I would consider paying more money
for an amplifier than many people spend on an entire audio
system. In this case, $4,000 seems a bargain.
John E. Johnson, Jr.
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Secrets of Home Theater & High Fidelity
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