This amplifier incorporates our proprietary Active Servo Bias, which guarantees an optimal operation since it does not require any polarization adjustment, always operating the output stage at pure Class-A to ensure a detailed sound scenario.
At the same time, the Active Servo Bias allows the use of different tubes such as KT88, KT90, KT120, KT150, 6550, without the need of any adjustment.
Zero negative Feedback
The U-280 SC 30th Anniversary LTD avoids the use of negative feedback, a common practice that results in a loss of details and sound richness.
To improve the damping factor without recurring to negative feedback, Margules Audio has developed the Back Electromotive Force Sensor system or BEFS, which changes the output impedance of the amplifier per the load requirement.
Efficient Power Consumption & Long-Life Tube Expectancy
The U-280 SC 30th Anniversary LTD is a low power consumption pure Class-A tube amplifier.
The Active Servo Bias and the BEFS ( Back Electromotive Force Sensor ) by continuously adjusting the polarization based on the signal rather than the tube characteristics, extend the tubes life expectancy, optimizing power consumption, reducing distortion, preventing overheating, and improving the damping control, resulting on the output stage to always operate in a full Class-A.
Triode / Ultralinear Output Configuration
The output stage valves can be configured through the simple operation of a switch ( triodes/pentodes ), changing the transfer function, optimizing efficiency and tonal characteristics.
Can be Used as a Stand Alone
This amplifier can work without additional pre-amplification thanks to its input attenuators.
Stereo / Monoblock
The U-280 SC 30th Anniversary LTD can be configured as a monoblock. This allows it to be used in conjunction with another U-280 SC 30th Anniversary LTD as double MONO increasing the power.
Low Distortion without Negative Feedback
The U-280 SC 30th Anniversary LTD power/distortion curve is uniquely low in a non-feedback and tube circuit, thanks to its redesigned Active Servo Bias.
Shunt Power Supply
The low-level signal circuit is biased by a Shunt power supply that has no correction circuit. By not having a control loop circuit, avoids the induction of non-desirable harmonics, guaranteeing the integrity of the audio signal.
ANA® ( Neuro-Acoustic Alignment ) Circuitry
The ANA® technology ( Neuro-Acoustic Alignment ) is one of Margules’ technological innovations developed from a fundamental principle: the human brain perceives sound by prioritizing the harmonic structure above fundamental tone; that is, it focuses on how humans perceive sound and not on how we measure it.
This technological advance originates from the seductive sound theory ( engaging sound ) and is based on the way in which our brain decodes the information from the sound waves through the ears: when sounds are closer, they keep us focused due to the relation between perception and sound, the distance at which we perceive them and their intelligibility, whereas distant sounds, even when intelligible, do not catch our attention and are easily ignored.
Our ANA® technology is designed to achieve a realistic sound, with a wide frequency response, low distortion, and accurate harmonic reproduction, optimizing to the utmost the relationship between the source and the receiver, so that you can enjoy your music in a way you have never experienced before.
Power Stereo Ultra-linear: 50 watt / channel
Power Mono Ultra-linear: 100 watt
Power Stereo Triode: 25 watt / channel
Power Mono Triode: 55 watt
Distortion: > 0.08%
Frequency Response: 20-40 khz
Max Power Consumption: 585 watt
Weight: 30.5 kg
Dimensions ( H x W x L ): 22 cm x 45 cm x 35 cm
Shipping Weight & Dimensions: 74 lbs, 23" x 20" x 13"