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We unite Innovation and technology in an amplifier that has become an international reference. It is a totally reliable system that does not require any adjustment and minimizes distortion.


You have the freedom to configure the U-280 in different ways.


If you want more power you use the Ultralinear mode and if you prefer a smoother and organic sound you switch to Triode. It can also change its power transfer characteristics by switching the output impedance selector, improving the power transfer ratio and the damping factor. Other option is making this stereo amp a monoblock by a flick of a switch.


Always operating in Class A to ensure a reach and full detailed soundscape.


This equipment can work without additional pre-amplification thanks to its input attenuators.


The U280 has the unique sonic stamp of Margules amplification systems.

Margules U-280 SC 30th Ltd Tube Amplifier

  • The U-280 SC Black is an amplifier with unique characteristics. Our proprietary active servo circuit makes the output stage always operate in pure class A without requiring polarization adjustments allowing the change of tubes without any modification. It also allows the use of different valves such as KT88, KT90, KT120, KT150, and 6550, giving the user the possibility to tune the unit to their liking.

    The continuous bias adjustment based on the signal rather than the tube characteristics, extends the tube life expectancy, optimizes power consumption, reduces distortion, prevents overheating, improves the damping control and allows the output stage to always operate in a full class A.

    The output stage valves can be configured through the simple operation of a selector, such as triodes or pentodes, optimizing efficiency and tonal characteristics.

    With its front switches, the amplifier’s impedance, power transfer function, and damping characteristics can be optimized.

    The U-280 SC Black can be configured as a monoblock. This allows it to be used in conjunction with another U-280 SC Black increasing its power to double. It also has an input level control per channel that can be used without a preamplifier.


    SHUNT power supply.


    The power sources of the small-signal stages are independent and of the SHUNT type. This type of source, as it does not have a control loop circuit, does not induce harmonics, thus maintaining the integrity of the audio signal.

    The SHUNT source is virtually indestructible thanks to its carefully designed circuitry to guard against common and uncommon bulb failures.


    The U-280 SC Black avoids the use of negative feedback, a common practice that results in a loss of detail and richness of sound.

    To improve the damping factor without resorting to negative feedback, Margules has developed the BEFS (Back Electromotive Force Sensor) system, which changes the amplifier’s output impedance upon load requirement.


    ANA® (Neuro-Acoustic Alignment).


    ANA® (Neuro-Acoustic Alignment) technology is a Margules innovation based on the way the human brain perceives sound by prioritizing harmonic structure over the fundamental pitch. This technology is about how we humans perceive sound, not how we measure it.


    This technological advance has its origin in the theory of seductive sound (engaging sound), our brain decodes information from sound waves through the ears: when the sounds are close, they keep us attentive due to the relationship that exists between the perception of these, the distance in which we perceive them and their intelligibility. Distant sounds, even when they are intelligible, do not attract our attention and are easily ignored.


    Our ANA® technology is designed to achieve realistic sound with appropriate frequency response, low distortion, and accurate harmonic reproduction, optimizing the relationship between source and receiver to the maximum so you can enjoy your music in ways that never before you had experienced.


    Power Stereo Ultralinear: 50w / channel

    Power mono Ultralinear: 100 w

    Power Stereo Triode: 25w / channel

    Power mono triode: 55 w

    Distortion: > 0.08%

    Frequency response: 20-40 khz

    Max power consumption: 585 w

    Weight: 30.5 kg

    Dimensions (height, width, length): 22cm x 45cm x 35cm

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