Margules I-240 Class A Integrated Amplifier


Margules Audio i-240 Class A Tube Integrated Amplifier

Reviewers Choice Award

The i-240 re-creates realistic and dynamic scenarios thanks to the fusion between the application of cutting-edge technology and the tonal benefits of the tubes:

The formula of Casa Margules’ Characteristic Sound.

This one-of-a-kind high-end integrated amplifier was handcrafted with materials and components of the highest quality, observing the strictest production processes and looking after the smallest detail.

Due to its manufacturing philosophy, the I-240 integrated amplifier merges design with functionality, offering versatility, convenience and, most of all, a realistic sound with an appropriate frequency response, low distortion and precise harmonic reproduction.

In the same way, this amplifier will allow you to enjoy a captivating, engaging and natural sound since its conceptualization and development are built on the implementation of our Neuro-Acoustic Alignment technology (ANA®) based on the way the human brain perceives sound, prioritizing harmonic structure over fundamental tone.


The I-240 is a tube integrated amplification and preamplification system (based on the legendary U280 ASB, which is a reference in the audio world) that recreates realistic and dynamic scenarios thanks to the fusion between the application of cutting-edge technology and the tonal benefits of the tubes: the formula of Casa Margules’ characteristic sound.

Class-A Operation & Active Servo Bias

This amplifier incorporates our exclusive Active Servo Bias (patent pending), which guarantees an optimal operation since it does not require any polarization adjustment, always operating at pure Class-A to ensure a detailed sound scenario.

By continuously adjusting the polarization based on the signal, this circuit radically extends the useful life of the output tubes and allows them an ideal operation, which in addition optimizes energy consumption by avoiding overheating.

Ultra-Linear Operation

The output tubes are configured to operate in ultra-linear mode in order to improve the efficiency in amplification.

Shunt Regulated Power Supplies

The power supplies for the small-signal stages are independent and of the SHUNT type.

By not having a control loop circuit, they avoid the induction of harmonics, guaranteeing the integrity of the audio signal.

Another advantage of the SHUNT power supplies lies in the carefully designed circuit to protect them from the common and uncommon defects of the tubes, which makes them practically indestructible.

Zero Negative Feedback

On the other hand, the I-240 avoids the use of negative feedback, a common practice that results in a loss of details and sound richness.

Back Electromotive Force Sensor

In order 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.

The optimal impedance of the equipment ranges between 4 and 8 Ohms, which is already pre-set. Hence, the BEFS together with the Active Servo Bias allow the amplifier to drive with excellent dynamics and controlled bass the difficult loads in low-efficiency or low-sensitivity speakers.


As to connectivity, the I-240 comes with three different line inputs and an attenuation or high precision volume control, which allow the use of the equipment with several sources.

Neuro-Acoustic Alignment (ANA®)

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 engaging sound theory 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 precise 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 at 8 Ohms: 25 watts per channel

Frequency Response: -3dB 10Hz – 40KHz

Total Harmonic Distortion (THD): 0.15% at 1 Watt 0.7% at Full Power

Bandwidth ( Full Power ): 30 – 30,000 Hz

Supply Voltage: 120 VAC

Electrical Consumption

Stand-by Mode: 145 Watts

Maximum Consumption:350 Watts

Vacuum Tubes:

4 x EL34 (6L6, KT66, KT77, 6CA7)

4 x 12AU7

Dimensions: 7.48″ ( H ) x 15.74″ ( W ) x 14.96″ ( D )

Margules Audio i-240 User’s Manual

Additional information


Margules Audio


Margules Audio

Our Story More than 90 years of history implementing out technology with special attention to the innovation and design. Today the fourth generation of engineers and craftsman are devoted to challenge the boundaries of audio reproduction. Each piece of our catalog is handcrafted to implement our innovation with chosen components to achieve our specific design philosophy, ANA® ( Acoustic Neurologic Alignment ), focused in how we as humans process and perceive sound, prioritizing the harmonic structure over the fundamental tone. Our efforts, knowledge and talent are focused in the design and manufacture of High-Performance audio equipment with our own technologic proposal to bring unsurpassed audio experience. Thanks to our innovative technology and the sound reproduction quality, Margules® is today a World reference in the high-end industry. MARGULES ® is also interested in creating sound oasis, making integral sound projects that generate captive and enriching audio experience in different spaces. 1925 In the Early twentieth of 20th century A Rumor is heard by a young European engineer, Mexican President, Plutarco Elias Calles is inviting capable man to participate in the National Electrification Plan. Jacob Margules sees this as an opportunity and an ideal pretext to construct a new life on America. Jacob asks for a loan to his father-in-law and crosses the Atlantic along with his wife, his dreams and capabilities. 1927 His talent as an engineer is rapidly recognized in Mexican land and plays an important roll in the first national radio stations. In this country our name has been link to the sound reproduction since its origins. Rapidly acquires the needed expertise to step up and found a store called Emporio Electronico, focused on selling and supporting the new radio industry. In a short time is the gathering oasis of the aficionados and professionals of the radio enthusiast, later turns in to Casa Margules. 1954 As a result of the success obtained in Casa Margules the business grows in to two, the distributing company, Radio Surtidora, and the manufacturing branch, Tel Rad, where we can find the born of our legacy, is here where we started manufacturing reproduction instruments, gramophones, turntables, amplifiers and speakers. When High Fidelity begins to be possible, the Brand Marvox was created, under that brand where produced several Amplifiers, Speakers etc. Tel Rad and Marvox project was headed by Alejandro Margules, second generation on the company. 1981 The accumulated experience and knowledge  thru does day and the new generation brings new ideas: Julian Margules, grandson of Jacob Margules and son of Alexander Margules, has the vision to use this baggage to implement his own ideas, the Magenta line is born, first as an high performance biamplified active system . 1990 After years of RD, Julian Manage to bring together his Ideas and experience in a project that became an Icon: The U-280 , the first servo controlled full class A amplifier with no need for any type of adjustments an unprecedented thermal efficiency. The U280 has been awarded throw the decades by the specialized critics and press, The U280 always has been in continuous evolution. Due unique characteristics  is a worldwide reference in the High End  Audio. Today, Margules, continuous working with the same passion in new technologies to reproduce the music with a natural and reach sound and exclusive aesthetics. Our Mission is clear: give the deserved place to your music and space where you listen, so you can enjoy it at its best. 2004 Margules makes the first high End iPod interphase, the “I-end” with one of the first electrostatic tactile panels in the market, video feedback, fully remote control throw RS232 o IR, and converted any I-pod in a music server with a high quality audio characteristics. In 2006 Sterephile reports over it and 2007 In the CES at Vegas is consider by NBC  news as a high light at the show. It was develop around our Analog to Digital Enhancer ADE, that has been mention by StereoPhile as a killer product and received awards by many other publications. 2018 Thanks to the growing demand on our product, and a continuous quality improvement requirement, the factory was relocated at a bigger and very well-organized facility.