Product Review - LLano Design Group SA-3 Monoblock Amplifiers - March, 1997

By John E. Johnson, Jr.


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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

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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