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Krakow Sonic Society, meeting #83:
Holger Fromme and his Avantgarde Acoustic XA Series

Avantgarde Acoustic Lautsprechersysteme GmbH
Nibelungenstrasse 349 | D-64686 Lautertal | Reichenbach

tel.: +49 (6254) 306 100 ǀ +49 (6254) 306 109



Text: Wojciech Pacuła
Photographs: Wojciech Pacuła | Avantgarde Acoustic
Translation: Krzysztof Kalinkowski

Published on: March 1. 2012, No. 95

This was not a classic meeting of the Krakow Sonic Society. Although we did something like that once or twice before, these couple times versus over eighty meetings in total is not much.
This time we did not compare anything, did not have listening sessions, did not plug anything in or out, etc. It was only about getting acquainted with a new, incredibly interesting product, the new, split amplifier Avantgarde Acoustic XA Series. And it was presented by no other than the owner of the company himself, Mr. Holger Fromme.
Let me tell you when we did this for the last time – please recall the meeting with Mr. Kazuo Kiuchi, the owner of Combak Corporation, meaning the brands Reimyo, Harmonix, Bravo! and the co-owner of the XRCD patent (Wojciech Pacuła, Krakow Sonic Society, meeting #72: Kazuo Kiuchi (Combak Corporation) in Krakow, „High Fidelity”, No. 73, May 2010; to be read HERE). Then it was a Japanese system and a person from Japan, this time we had a German device and a person from Germany describing it to us. Japan and Germany – a coincidence? Rather not, as noted by Janusz who has also been many times the host of our KSS meetings; when the Japanese and the Germans work on something there is a big chance that everything will be done just right. And when exceptional people are involved, outstanding products are created. Like the new XA series amplifier (price: 9000 euro + 9000 euro).


This is another example that on the one hand specialization is good, that when somebody is dealing with electronics, then loudspeakers are only an addition to the portfolio; on the other hand, when somebody is specialized in loudspeakers, electronics becomes the add-on. And this is how it usually is. That is why the appearance of a very expensive amplifier, the result of many years of research in the offering of the German company Avantgarde Acoustic, a loudspeaker specialist, could seem to be a whim. But in this case things are more complicated than they might seem at first glance.

Avantgarde Acoustic is a company specialized in making “horn” loudspeakers. Their characteristic “hats” make the company well recognizable and having a clear identity. Horn loudspeakers, besides their assets, like high efficiency and fantastic transfer of energy, usually have issues with reproducing low bass – to be able to do it as well as classic speakers, they need a very big diameter of the bass horn, which is very difficult to attain from the practical point of view. This is why most AA loudspeakers are equipped with an integrated subwoofer, and the biggest model Trio is supported by mighty, horn, active subwoofers Basshorn. And active subwoofers mean ‘amplifier + loudspeaker’. This is one trail.
The second one is clearer – Matthias Ruff, the man responsible for the products of this German company, for years have been designing for his lab amplifiers that used to drive the loudspeakers he designs. As he told me on many occasions (he even was once in Krakow), he always thought that solid state amplifiers are best to drive horn loudspeakers, as only those can guarantee the noise and distortion low enough to not be audible with the horn speakers and only those are capable of powering such constructions.

His efforts turned into commercial products – Avantgarde Acoustics presented their first integrated amplifier Model 5 long ago. I used it for a longer time, and I have to say that despite its low output power (27 W/8 Ω) it surprised me many times. And this was because it had a very simple construction –there were only five elements in the sound path, the feedback was minimal and the circuit very quick. It was replaced by the Model 3, a bit more powerful and bigger, and finally the mighty, housed in four cabinets, system Model One – preamplifier with a separate power supply and two power amplifiers.
But this was not enough for Matthias. According to Mr. Fromme, the constructor kept on talking that he wants to make the best amplifier possible. And he talked, talked, talked… Finally the owner of Avantgarde told him “do it”. And so the quest started, finishing in the beginning of this year in the form of the XA series.
It took a long time before this amplifier was made. If I remember well, already four years ago I heard that something would come; three years ago and two years ago came some prototypes, including a phonostage and a DAC, and last year the finished amplifier and preamplifier were presented. But still without a listening session…

eXtreme Amplifier – THE ROAD TO THE IDEAL

Holger Fromme is a very soft-spoken man. He came to visit us, because the XA Series is the light of his eye, something he fully believes in and in which he is fully engaged. He designed the exterior looks himself…
As it turns out, a few people worked on this project almost endlessly. “My role was to create something exceptional. This is why we paid attention to the smallest details. Even the logo was made after a long search – the company responsible for this prepared 50 different versions, from which we composed the final one. Everything counts there, the combination of the letters X and A, and even the minimal rounding in the places the oblique elements are bound, visible only when enlarged”. A similar, almost fanatic attention to detail can be seen in the whole construction.
“You see, the Avantgarde Acoustic is a family company – 75% belongs to me and 25% to my father, whom I asked for help long time ago. So there are no investors, co-owners, etc – nobody is pushing on us. For us only the final effect is important, not quick money”.

XA is an acronym for ‘eXtreme Amplifier’. “Because everything in it is extreme”. It starts with the innovative amplifying circuit, based on ‘Constant Current’. Normally, when signal appears on preamplifier input, it is amplified and in this form it appears on the output. If there is no signal, the amplifier does not amplify anything and the current does not flow.

But the problem is the crossing of zero – when we magnify the sinus wave far enough we will see oscillations there, coming from the imperfections of the amplifying circuits. In the XA a current with a voltage of 6-7V flows all the time through the circuits and is modulated by the input signal. Such ideas were known earlier, but people could not handle switching inputs or controlling volume in that setup. In the XA a classic potentiometer, in the form of a damper or a resistor ladder, could not be used. “We managed to create a version of the ladder, with 48 resistors keyed by transistors – each resistor has a LED around the volume knob. On the output the signal is filtered in a special circuit – there cannot be any DC voltage, as it would destroy the amplifier and loudspeakers. We also set the attenuation differently than usual. In most amplifiers full power is available at one o’clock – above that it gets higher and distortion is produced there. That is why many people think first that the XA PRE sounds quiet. This is purposeful – amplification is available during the full stroke of the volume knob”.

The preamplifier and power amplifier were built without using negative feedback loop. This is something that was the goal in the previous constructions of Matthias, but could only be fully achieved here. But this is not the most important thing – the PRE is powered by batteries, and not from the wall socket.
“If you are building an amplifier without a feedback loop, then each element has a big role to play, because nothing can be corrected after the fact. The quality of the individual components is also important. I will talk about the power supply in a moment, but first I would like to tell you about the components we used.
Each capacitor in the sound path, and also in the parallel branches, was audited by us thoroughly. It turned out that not always the most expensive one was the best; everything depended on the place it was used. To choose the best ones, Matthias prepared three identical preamplifiers with different capacitors inside. We listened to them in series and eliminated the worst one. In the end we got the best sounding one. So we did exactly what you are doing – we were listening… The same thing was with resistors, sockets, etc. We chose for the parallel branches the Black Gate capacitors, not manufactured anymore capacitors designed by the Japanese and manufactured by the company Rubycon on a license. Because their production was terminated in 2006, to be able to have a sufficient amount of them, we spend over 50,000 euro to buy as many of them as possible on the market. Also the transistors are special – normally you can buy such elements for 1 euro a piece, we pay over 10 euro. This is because Matthias chose their special version with guaranteed characteristics.”

Let’s add that AA used the Black Gates before, in the Model 3 and later in Model One, but not in such quantities. In the Model One another “patent” was used, which was taken to extremes in the XA: the preamplifier is powered from batteries, and in the power amplifier they used a stabilized power supply with a gyrator. “Power supply is a stupid name for what the unit is doing. In fact, this is a unit used to transfer energy, to keep it circulating. It does not “supply” anything”.

And finally the enclosures. As you can see on the pictures from the High End 2011 show (reportage HERE) the units have in fact two cabinets – an internal and an external one, both made of thick, aluminum components. “We had to buy the machine used to make those. Those are cast elements finished using the CNC machine.” This allows minimizing vibration – something Matthias pays special attention to.
But this is not all. “I wondered for a long time, why the audio branch is not so refined. When somebody buys a Jaguar car, then everything can be custom made – from the varnish to the finish on the steering wheel. Why this cannot be done in high-end? Often money is comparable…”
This is the reason that XA series can be adjusted to individual taste. The fronts can have their metal components black or silver in different combinations. The front panel can be finished in many variants of wooden veneer, metal sheets painted to different colors, etc. Each amplifier also gets an individual owner plaque, with his or her name milled.

Mr. Holger Fromme is a very nice man. A man with a passion. He is the owner of a pretty big company, not an engineer (which he underlined himself many times), and yet he was perfectly prepared for the meeting. I am sure that he spent a lot of time with his engineers, especially with Matthias, before coming to us, to learn and discuss. He just wanted to convey everything that could be said about the amplifier, so that we could share the same excitement. Did he succeed? I can only tell for myself: I am greatly impressed by his professionalism.
But he says himself: “Times have changed. Now it is not the dealer who tells the client what to buy. First the client looks to the net, then he listens in the audio salon and searches the net for information again. In our opinion this is a valuable change! It makes the companies increase the quality of service to have a better contact with the clients. It also allowed us to change – hence the films we recorded to explain the ideas behind our products, or high class photos. This is a step in the right direction. When we want to treat the client well, we have to do our best. Otherwise we will lose him.”

Distribution in Poland: Eter Audio
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