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SA-2 Two Channel Amplifier

SA-2

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Dedicated Power
The Wisdom Audio amplifier/speaker system is designed to take advantage of a fact that has hitherto been understood only by a relatively small number of audiophiles: speakers sound better when they are driven directly by dedicated, high quality amplifiers.

You might think that you have done so in the past. After all, you connected your receiver or amplifier directly to the loudspeaker cabinet, using high quality wire. But in almost all cases, that connection led to a passive crossover network within the speaker cabinet, made up of resistors, capacitors and coils of wire called inductors. The passive crossover had the job of splitting up the signal to the woofer, midrange, and tweeter inside the cabinet. By design, it created a complex, reactive circuit between the amplifier and the drivers that actually make the music.

Active speaker systems like those in the Sage Series and Wisdom Series bypass the passive crossover in the speaker by moving the crossover ahead of the amplifiers. The SC-1 is such an active electronic crossover. It electronically divides the music signal while it is still at a preamplifier (line) level, allowing great accuracy and consistency. These separate signals are then routed to dedicated amplifiers which need work with only a portion of the audible range.

This approach is called "bi-amplification" since each speaker is actually using two channels of amplification. While obviously more costly to implement, bi-amplification provides several important benefits:

  • Greater excitement due to improved dynamics. Obviously, having two amplifiers allows you to use more power on a per-speaker basis, but this is about more than simply playing loudly. The moment-to-moment dynamic contrasts are vastly improved, thanks to the fact that the inefficient buffer that would have been the passive crossover is missing. The amplifiers are connected directly to their respective drivers, so every nuance in the signal is preserved.
  • Improved detail and intelligibility thanks to lower distortion. One major source of loudspeaker distortion — the passive crossover itself — has simply been eliminated. Plus, each amplifier has a simpler task, being responsible for only part of the audible spectrum. This fact reduces several types of distortion, most notably clipping (since all of its power is available for less work) and intermodulation distortion (since the amplifier sees fewer frequencies).
  • Improved clarity and control. The amplifier's "damping factor" is one way of measuring its degree of control over the motion of the driver to which it is connected. Unfortunately, when a passive crossover intervenes, the amplifier is no longer directly connected to the driver it is asked to control. As a result, it loses much of the precision its designers worked so hard to achieve. By avoiding the need for a passive crossover and connecting directly to the transducer, the amplifier's ability to control the motion of the diaphragm is maximized.

In fact, many Wisdom Audio systems take this multiple-amp-per-speaker idea even further. When you add one or more dedicated subwoofers that handle only the deepest bass, the system is "tri-amplified." That is, you enjoy the benefits of having separate, dedicated amplifiers and drivers handling only the deepest bass, then the rest of the bass, and then the midrange and high frequencies (on the planar magnetic drivers).

High Efficiency
The benefits of enormous power reserves are fairly obvious: freedom from any audible strain, greater dynamic impact, and the ability to hear music and movie soundtracks at their intended volume without worrying about whether the system can handle it.

However, the traditional methods for achieving this required level of performance involve bulky, heavy designs that generate a great deal of heat. When you multiply the number of channels required for a modern home theater application times two (for bi-amplification), and add in one or more dedicated subwoofers, suddenly you have need for smaller, more efficient amplifier designs.

The system amplifiers used to drive the woofer sections of your Sage series loudspeakers from Wisdom Audio fit the bill nicely. While many contemporary amplifiers waste 50% or more of the power they pull from the wall as heat, the SA-series amplifiers run at approximately 90% efficiency. As a result, more power is available for the loudspeaker, and less is wasted as heat in your room.

The high efficiency of the SA-series design also means that the amplifiers can be placed in close proximity to each other, as in an equipment rack, without undue overheating. Of course, care must be taken to account for the heat generated by other components in the rack; but the Wisdom Audio amplifiers will not greatly contribute to the thermal management challenges of your system.

Small-Box Compensation
People today want the best of everything. When it comes to their home entertainment systems, they want high performance while having relatively low impact on the décor. This desire becomes even more important in a home theater situation, in which there might be six to ten speakers in the room. Having that many large, imposing loudspeakers in a room is simply not on most people's wish list.

The Sage system has been designed with this reality in mind. The enclosures are quite compact, which would normally limit the bass performance rather significantly. But thanks to the remarkably robust design of the woofers developed for the Sage system, we can compensate for the unusually small enclosures with the addition of extra power.

The notion of trading power requirements for small size has been used extensively in subwoofer designs for over thirty years, and is well proven. Wisdom Audio has now brought these same benefits to the main speakers, in order to achieve outstanding bass performance in speakers of modest size. The Wisdom Audio SA-series amplifiers were designed from the outset to provide the extra power required by this approach.

Please visit our Where To Buy page to locate your closest authorized Wisdom Audio dealer in North America, or International Distributor in markets outside North America.

SA-2 Specifications:
All specifications are subject to change at any time, in order to improve the product.

Rated power output per channel 500 w/ch continuous rms power @ 4Ω above power ratings
from 20 Hz–20 kHz at <0.5% THD
Peak output current > 30 amps
Voltage gain 31 dB
Input sensitivity 1.2V for full output
Input impedance 25 kΩ (balanced)
Polarity Non-inverting, Pin 2 positive
Signal to Noise ratio (main outputs) –103 dB (ref 1V rms, A-wtd.)
Output impedance less than 0.05Ω from 20–20,000 Hz
Thermal load 7 BTU/minute or less
Mains voltage 100V, 120V, or 230/240V determined by the needs of country for which the unit was manufactured; cannot be reset by dealer or user
Shipping weight 40 lbs. (19 kg)

Power consumption,
SA-3

1870W (±5%) at full power, all channels driven
Power consumption,
SA-2, SA-1
1255W (±5%) at full power, all channels driven
Power consumption,
all three models
10W (±5%) at idle and 2W (±5%) in standby

This component has passed independent certification and testing by the internationally recognized testing laboratory TÜV SÜD for worldwide operation. Learn more about TUV here.

Owner's Manual
SA-2 Owner's Manual

Literature
SA Amplifiers Data Sheet
Sage Series Brochure