Publisher Profile

Margules Audio U280-SC 25th Anniversary Stereo Tube Amplifier

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Margules Audio U280-SC

 

Who is Margules Audio?

Julian Margules of Margules Audio has been delivering audio for over 40 years and is well known in Mexico and other parts of the world. Still, I had never heard of them until 2010 and never heard one of their products until one of the early California Audio Shows. Margules Audio is located, and their products are manufactured, in Mexico City.

Ben Goldman of Integrity High Fidelity Solutions is the American point man for these products. According to Ben, Margules has always been a family-owned organization that researches, designs, and manufactures amplifiers, preamplifiers and loudspeakers. The history of the family business dates back to 1926 when Jacobo Margules founded Emporio Electrico, specializing in electronic components for radio broadcasters, radio amateur operators, electronic service technicians and electronic students. The name of the company became Radio Surtidora S.A., which is the oldest organization in Mexico. Currently, Radio Surtidora specializes in electronic measurement equipment and industrial electronic components, while the Margules side handles the sound reproduction field and high fidelity business. So, you should feel good that you are dealing with a long established family business if you choose to purchase a product from Margules.

 

Description and Design

Simply put, the U280-SC 25th Anniversary amp is s a Class A tube amplifier that can operate in either ultra-linear or triode mode. Over the years, I have found time and time again that I much prefer Class A amps, whether they be tube or transistor. To me, Class A amps simply sound right, they sound much more like real music. The U280-SC is a Class A push-pull design, and it can also be used as a stereo amplifier, or if you purchase two they can be used as mono-blocks. In ultra-linear mode as a stereo amp, the Margules delivers 80 watts per channel into 8 ohms. If you use triode mode, it delivers 40 watts into 8 ohms. If you use two as mono-blocks, it doubles the power in both modes.

The U280-SC amp uses a Class-A output stage with what they refer to as “Active-Servo Bias.” The servo-bias actively tracks the input signal, permitting full class-A output, without overdriving the tubes. According to Mr. Margules, the “Active Servo Bias” also sets DC bias and AC drive levels. This assures that optimum electrical and sonic performance is provided by the amp at all time. It also means that throughout the useful life of the output tubes, no drive or bias adjustments are ever needed, regardless of what tubes you choose to use. The “Active Servo Bias” is implemented with semiconductors, which were designed for the aerospace industry. The New U280-SC 25th Anniversary Stereo Tube Amplifier includes a new and improved differential output as well, resulting in further reduction of THD and transient distortion. The input stages of the new 25th Anniversary version also include a special SHUNT power supply for the critical circuits. The shunt technology is there to provide an improvement in the Q damping, one of the key factors in regulating voltage for those stages.

The amp is switchable between triode and ultra linear operation. It also allows the outputs to be strapped, for twice the output; so you can use two as mono-block amps. This would allow you to use the triode operation at the same power level as the ultra linear on a single amp. There are separate gain controls for each channel, which make precision balancing easy to simplify further the setup of bi-amped systems. The U280-SC uses no negative feedback, which is a plus in my way of thinking.

There are a few very useful control features on the top of the amp, in front of the tubes. There is a toggle switch to the left of the output tubes to switch the operating mode from triode to ultra-linear. On the far left is a knob for selecting whether you want to use the amp as a stereo or mono amp. Then, there are selectors for the correct ohms for both channels. You might ask why would anyone need this but if you are vertically bi-amping, this might come in very handy. Lastly, there are two knobs for GAIN. I always appreciate amps that give you this option. It helps to get the best out of your preamp’s volume control. Also, with all the preamps that don’t have balance controls these days, it solves that problem as well.

The build quality of this beautiful amp is very nice. The Margules U280-SC is very heavy, with all the weight in the back. Be careful lifting or moving it. It has silver plated circuit boards and gold-plated switches. It is designed not to push the tubes hard so that you can expect long tube life. I also am very taken with the way it looks. It has a classic tube amp look without looking old-fashioned. Everything about it looks like it should cost at least twice its asking price.

 

Talking with Julian Margules

It was my privilege to spend some very pleasant time talking to Mr. Margules himself about his audio products. The first thing that I noticed was his passion for designing musical sounding equipment that portrays the emotions of music. The second thing I noticed, and he even spent more time talking about, was his even greater passion for classical music. This was not the passion of a sales person or an audio engineer, but of a man passionate about listening to music that moves him emotionally and spiritually.

Mr. Margules shared with me his love for Class A sound, and his ideas about the technical aspects of the amps designed to get the most out of a Class A amp. I shared most of what he had to say about this with you in the previous section. What he talked most about was his view about what he expected from the audio system he designs. He said a system need to “sing”! He shared that he believe art is the way we communicate with the human soul. This means that the art of music is all about how it makes you feel deep inside your soul. Thus, it is the job of an audio system to communicate to your soul how the music was meant to make you feel, the emotions of the performance both high and low.

7 Responses to Margules Audio U280-SC 25th Anniversary Stereo Tube Amplifier


  1. John Chaney says:

    I use this amp with both my Fulton J and Dunlavy SC IV speakers. Even with the Fulton Js I prefer the triode setting. I am getting all the tonality, detail, dynamics, and emotion I could want!

  2. David Deboys says:

    A small note to say a large Thank You from across the pond for your illuminating reviews. I am currently using Nelson Pass’ First Watt F6 into efficient Living Voice speakers. Your review of this delightful looking amp tempts me to return to valves – speaking of which I don’t believe you indicated what output valves you were listening to. Could you clarify, please? Thanks!

  3. Carlos Smith says:

    May I suggest that you review this amp with Margules Audio┬┤s SF220 preamplifier? It has been my pleasure to have enjoyed this setup on several occasions with Julian Margules in his demo room, just across the hallway from his workshop. Julian is a fine and patient host and he will work with you to provide the best system for your needs and at very competitive pricing, as will Ben Goldman- the US importer. By the way, I have been the proud owner and user of a u280 amp for years with the bespoke preamp (and other Margules Audio processing equipment) with the following results: amazing and beautiful sound and soundstage across the entire frequency range (with large Meadowlark Nighthawk speakers), great dynamics, luscious presence, and rock solid dependability. Your readers will be well served by your findings.

  4. Z. Al says:

    Thanks Jack for the great review, I am so convinced I wanna ask your advise on pairing them as Mono’s with a couple of Klipschorn Floorstanding Speaker from their Heritage series.. I recently heard those at a friends house and I can’t seem to get them out of my mind, and at that price they are literaly giving them away. Any thoughts, highly appreciated?

    Cheers,

  5. Andrew Singline says:

    Is there an agent in Australia for Margules u280-sc 25th anniversary amplifiers

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