've been trying to remember how long have we known each other with Mr Eugeniusz Czyżewski and I've realized it's been 12 years already. The Pracownia Elektroniki Przemysłowej ORLIK, as Mr Czyżewski's company was called back then when we met, was just about to change its name to Argos and it was Argos IA-45 Integra, a tube amplifier that I reviewed in September 2003 for „Sound and Vision” magazine. I truly loved this device and not only because of how it sounded, but also because of other features like: reliability, robustness, a solid production plan and its perfect execution, utmost attention that was given user's safety issue, and a design that was created to offer many years of smooth, issue-less operation. One might think that these are all features of any high-end device, it could seem that this is what customer pays his money for, but in many cases it isn't. In fact the reality seems to be quite different – it is mass products that seem to be more reliable and safer to use. Obviously that doesn't have to be true in every single case but it is in most of them.

IA-45 Integra, was an „Integrated Amplifier” delivering 45 W per channel manufacturer offered the same device as power amplifier) and if was different than most other products on the market. It didn't look as attractive as many mass products, or even as some audiophile ones. One started to appreciated after taking a peak inside or/and listening to some music using it.
It turned out that it would be the first of the whole series of integrated amplifiers to come. Mr Czyżewski was in fact conducting tests of different designs, technologies and topographies. Some had wooden front like the 2005 IA-45 MkII, some had a metal one like 2009 IA-120. The latter was the first fully solid-state amplifier, with external design that became a standard for most products to come – there was a metal casing with a silver element in the front and with wonderful, round VU-meters with warm, yellow back light. Already the first unit using this design was sold under a new brand called Linear Audio Research, that, as you already know, became the one used until today. Not until last year did we see the new company's logo – it was presented together with a second version of tube integrated IA-30T (MkII). In this way, 12 years after I first encountered Mr Czyżewski, his company finally settled with a final name, logo and quite a characteristic looks of its products.

Mr Eugeniusz is not a kind of man who rushes things. His experience from his jobs in research institutes and few different industries (including arms) gave him an opportunity to find his own way of getting where he planned to without unnecessary rush. It gave him also a solid engineering base, experience and knowledge. He started his carrier in 1972 in Instytut Metrologii Elektrycznej at Wrocław University of Technology, where he specialized in electronic measurements, and in 1979 was awarded a Doctor of Science title. His reluctance to change things quickly is obvious also if check out company's webpage that hasn't been updated for quite some time, and which reads:

For my designs I use both tubes and analogue integrated circuits. My goal is to explore their best features. Manufacturing process uses industrial standards even though my products are made in small batches.

IA-120H is the first LAR's amplifier that combines tubes and solid-state elements. It's preamplifier stage was taken from tube integrated, IA-30T MkII, and the design of power stage came from a solid-state amplifier, IA-120.

A few simple words…
EUGENIUSZ CZYŻEWSKI
Owner, designer

WHY A HYBRID?

I have been thinking about a new integrated amplifier for quite some time now. I wanted to avoid one of the biggest downsides of tube amplifiers – significant heat emission. Using tubes usually means that the warmer they get the better they sound. Using such amplifier during summer might be a real nightmare, unless, of course, one has a listening room with air condition. The solid-state designs usually dissipate much less heat. The problem is that it is only tubes that are capable of delivering natural, warm sound. To solve this issue I decided to build a hybrid amplifier, a one that combines tubes with solid-state elements, and each of them has its role to play:
• the first stage sports tubes whose grid is driven directly by input signal,
• the volume control is applied right after this first stage,
• the output/power stage is a symmetric solid-state design sporting MOSFETs.

An input selector based on relays precedes two identical amplification paths. Power supply had to be upsized for this dual mono design. There are two main transformers and two power supplies with quick diodes and large capacitors and auxiliary power supplies for tube input stage, input selector and VU-meters electronics. A special attention was paid to tube's power supply – each triode has its own voltage regulator that ensures the same operating voltage regardless power grid's fluctuations. Choosing a proper tube for input stage wasn't easy. The famous ECC88 doesn't really work too well with high signals, and that's what one gets from most digital sources. It's is also not to powerful tube and same goes for all its “cousins” like: ECC81, ECC82 and ECC83. So I chose large, more robust tube, that was designed for audio purposes and used successfully in many audio devices from BAT, Ancient Audio and AYON. It is 6H30Pi, neutral sounding, linear and delivering enough power to efficiently drive volume control.

Transistor's choice wasn't really any easier. Bi-polar transistors would be obvious, easy choice, but these don't guaranty beautiful sound, as they create to many odd harmonics. SO the only reasonable choice were MOSFETs. There are a lot of them on the market by I decided to chose the ones that worked so well in AMPEG's instrument's amplifiers. It is possible to build a design based on these MOSFETs that would sound similar to tube amplifier while offering much better bass control.

Take a look inside – you'll find a symmetrical design with transformers and power supplies on side walls, power stages placed on the platform in the middle, tube preamplifier section in a front, and two VU-meters and two knobs on the front panel. One of them allows source selection, the other volume control. Headphone output is placed under left knob. Stick large jack in and the speaker output is automatically cut off and additional loading is put to power amplifiers.
While keeping the size and weight at reasonable levels I was able to achieve 120 W output power per channel, a very satisfying sound, and the looks and aesthetics bring IA-30 Mk2 to mind. There are some differences though. This time I used wooden side panels with gloss finish, and the main color is also bit darker.

March 31st 2014

This text was originally published as a comment to our 10/10 contest, that we created to celebrate „High Fidelity's” 10th Anniversary in April 2014, see HERE. Ms Elżbieta Więcek won a special version of IA-102H for a short story 10 łatwych utworów na fortepian based on Preisner-Możdżer duet's album.

Recordings used for this test (a selection)

• Aquavoice, Memoris, Generator GEN CD 011, CD (2009).
• Charlie Haden & Chris Anderson, None But The Lonely Heart, Naim naimcd022, CD (1997).
• David Crosby, Croz, Blue Castle Records BCR1142-1, CD (2014);
• Faust, Faust, Polydor/Universal Music LCC (Japan) UICY-75652, “European Progressive Rock Collection, Vol. 1”, SHM-CD (1971/2013).
• Jean-Michel Jarre, Revolutions, Disques Dreyfus/Polydor CD 837 098-2, CD (1988).
• Kanaan, Duda, RudĽ, Hołd, Solition SL 380-2, CD (2014).
• Laurie Anderson, Big Science, Nonesuch 79988-5, “Expanded and Remastered for the 25th Anniversary”, CD (1982/2007).
• Martin Kratochvíl & Jazz Q, Temné Slunce, soundtrack, GAD Records GAD CD 018, CD (1980/2014).
• Niemen & Akwarele, Czy mnie jeszcze pamiętasz?, Polskie Nagrania MUZA/Polskie Nagrania, PNCD 1572, CD (1968/2014);
• Patrick Noland, Piano Gathering Light, Naim naimcd011, CD (1994).
• Skrzek & RudĽ, The Stratomusica Suite, Generator GEN CD 032, CD (2014).
• Urszula, Wielki odlot 2. Najlepsze 80-te, Universal Music Polska 378 577 4, CD (2014).

Japanese issues available at

Choosing one technology or solution over other seems to be something more than a simple decision about the sound. Most manufacturers would tell you otherwise but I think that it is me who's right. I think that most such choices are based on some believes, some ideology rather than truly technical choice, based on hard facts. In fact in our industry we talk more about believes, ideology than about hard facts. That's why there are some many “audio-wars” where people fight really hard defending their believes that one solution/technology is better than other. And it is not even about any kind of objective truth, of what's really better – any ideology does not accept any other truth than its own. One of such old but still on-going “wars” is the one: tube vs solid-state in amplifiers. Billions of words, millions of pages where written trying to prove one of these outcomes. It has never brought us any closer to one commonly accepted truth.
So I think that it does not really matter what will I write about Mr Czyżewski's amplifier – it's will be perceived via it's hybrid topology. Both sides of the conflict usually perceive such designs as an attempt to bring water and fire together, or in other words to combine “softness” of tubes with transistor's “raw power”. I got used to running “missions impossible”. Most of them turned out to regard important, or even turning points of audio industry's history so I'm always ready to take on a challenge like that.

That might sound a bit surprising but despite its hybrid design the reviewed amplifier sounds a lot like tube IA-30T. In both cases the designer wanted his amplifier to sound as neutral as possible, without any coloration, meaning without anything added or deducted from the sound. So it is about true neutrality and not just about not “adding” something to the sound, but also about not losing anything. On the other hand it seems that IA-120H has more distinct sound signature, it looks like the designer wanted to to something to clearly deny any stereotypes. This hybrid offers a quite specific sound and one has to consider that when building one's stereo system around this device. One will find a bit richer than usually upper bass and lower midrange, bit conservative upper midrange and quite rich upper treble. It results in a bit warmer sound that one would expect from a solid-state, but also richer, and more open so one has to carefully select remaining elements of the system.

In my opinion the most distinct feature of this amp is how amazingly it does differentiate sounds. Maybe not all of them (I'll get back to that in a moment) but comparing this device to any competitors at 10.000 PLN price range this feature stands out most. It offers outstanding bass differentiation. Whatever music one might want to play one thing will always be sure – there will be a proper bass foundation to the sound and it will support perfectly the upper part of the range. LAR does enlarge instruments playing bass tones. Not by much but still and that's why the upper bass seems so powerful. Despite that one can still tell the way bass guitar's sound is conveyed, what sort of attack was chosen for electronic instruments and what sort of reverb was put over them. I had no doubts that bass guitar on the re-issue of Niemen & Akwarele's Czy mnie jeszcze pamiętasz? prepared by Ms Eleonor Atalay and Jacek Gawłowski (who was involved also in Jacek Pawlik's recording that received Grammy Award), was significantly better than in first digital re-issue and also than in the last one that was issued still when Mr Czesław was with us. Its differentiation was better, tonality was nicer and it was surely more energetic. The box re-issue from „Niemen od początku” series delivers a boomy bass, hardly acceptable. At least when played via a fast system that differentiates dynamics in a very good way like a LAR amplifier does.

After changing repertoire using different recordings I received a different output. Honoring the great, recently passed Charlie Haden (Aug 6th 1937 – July 11th 2014) I listened to None But The Lonely Heart album he recorded with Chris Anderson. It was recorded by Ken Christianson using True Stereo system (although there is no proper logo on the cover; see the interview with Ken explaining that HERE) and mastered by Naim's chief, also late, Julian Vereker (May 7th 1945 – January 14th 2000), and it's a beautiful, nicely played set. It might not be some innovating piece of music but id I don't think it was ever supposed to be. That's a recording of a meeting of two great musicians who understand each other very well, and have fun playing together. And it was IT that this Polish amplifier showed effortlessly very well somewhere under the layer of beautiful music. The sound at first seemed distant and lacking a bit of a sparkle (that's how True Stereo is usually perceived at first). But with each stronger accent sound became truly vibrant, lively and the sound seemed very natural. That's a characteristic feature of Christianson's recordings that gets listeners truly involved with music.

Such a great bass is a fantastic base, foundation for the whole range no matter what music we listen to. Without bass there is no midrange. It helps to achieve a proper volume of sound, including proper presentation of the size of the room where music is performed/recorded.
Sound delivered by IA-120H is quite large and agile. It involves a slight roll off in upper midrange. At first sound might seem warm and a bit “closed”. Voice don't “jump” in front of speakers, they even seem a bit infused into the mix. One could say that this is a perfect example of a hybrid design. But it is not so. The upper treble is strong, and well defined. One of members of Cracow Sonic Society listened to LAR for a few days in his system with Castle Knight 5, rather warm sounding speakers, with Cambridge Audio DAC100, a converter offering open sound, and according to him this amplifier was bit too bright for this system. In fact it clearly showed the character of the system. Speakers weren't warm anymore, as they were finally properly driven. That's obviously not a downside of this amplifier – it is its feature.
In my system I perceived it as treble being more open. It's bit more crisp, not as soft as IA-30T's, nor in any other “warm” amplifier. I think that it's a treble characteristic rather than how much treble one gets that needs to be evaluated in particular system.

IA- was the first amplifier from Kamieniec Wrocławski that offered headphone output. And in fact it was just an option – something for me to “play with” (I think I conducted all first tests of LAR products except for IA-30 MkII, that was reviewed by Marek Dyba HERE). Where the idea of headphone output came from? I think Leben CS-300, a Japanese integrated amplifier used by many people around the world also as headphone amplifier, was the source of this idea for Mr Czyżewski. I also am one of happy users (see HERE and HERE). For IA-30T MkII headphone large jack output was a standard, but it is IA-120H that finally sports this output on the front panel as one of key features.
Headphones receive signal from solid-state power amp and not from tube preamplifier. When headphones are plugged in speakers outputs are automatically cut off. Such a setup “forced” me to grab one of the most demanding cans I knew, the HiFiMan's HE6 flagship and plug it in right after I unpacked LAR. So far only Bakoon HPA-21 and HiFiMan's own EF-6 (that I'd reviewed for „Audio”) were able to drive them properly. But as it turned out it was IA-120H that let the HE-6 truly shine.

HE-6 often sound too bright or even aggressive, flat, uninvolving, lifeless. I heard them play in each of these ways. Each and every time it was a case mismatch between amplifier and cans, and not a problem with cans themselves. If you have any doubts about HE-6's capabilities try them with IA-120H – you will finally hear what this planar magnetic headphones are capable of.
It is not difficult to describe the sound of such a setup. One starts to enjoy it over first few seconds of listening. It's a rich, powerful, dynamic presentation. The presentation of low end is. If one had ever heard these cans too bright or lacking lowest bass, one wouldn't anymore. These cans designed by Mr He offer an amazing sound when combined with IA-120H. Even the spacing and imaging, which are not strongest points of HiFiMan's performance, improve with LAR significantly. It seems that all that is due to unlimited power and dynamics this amplifier provides. Don't let in to the temptation of cranking volume up and up as at some point, especially with classical music and uncompressed recordings some cracks and pups will appear in the sound – it will mean that you definitely went too far with volume pot. So be careful – remember that your ears can only take on so much.

HE-6 with IA-120H plays equally well krautrock's electronic music, progressive rock ELP, jazz, and classic music. In fact it doesn't really matter what one decides to listen to. Each time the result will be the same: a smooth sound of amazing depth and dynamics, with extremely smooth treble and rich lower midrange.
Leben CS-300XS is considered by many to be a perfect match for AKG K701 and Sennheiser HD-800. I can confirm that as I own all these devices. But Linear Audio Research with HiFiMAN offers even better sound. And I mean in all aspects. Nothing to add here – all should be clear.
No, I can't stop here, I have to add one thing: I perceive this setup as iconic as the one created by Peter Walker. I mean, obviously, ESL speakers (ESL-57) and QUAD-II power amplifiers. Sonic signature of the sounds of these two systems is very similar. As any and every system also these two have some limitations. Since I mentioned ESL speakers I'd like to quote a phrase that ends their description in Robert Harley's The Absolute Sound’s Illustrated History of High-End Audio. Volume One: Loudspeakers:

As for their [ESL-57 speakers] supposed shortcomings my answer is a paraphrase of famous Randall Jarrell's words about certain fragment of Whitman's: there are limitation to this design but they simply mean nothing.

The Absolute Sound’s Illustrated History of High-End Audio. Volume One: Loudspeakers, Editor ROBERT HARLEY, Nextscreen, Austin 2014, s. 22.

Summary

In my review I focused on how this amplifier creates a bass foundations for the whole sound and how well it differentiates sounds. Not because it does other things in a worse manner but because these two particular elements are something that most audio devices miss regardless of the price range. IA-120H offers impressive dynamics, very tuneful, colorful bass and midrange. Its treble might be bit more specific, so one needs to “digest” it in one's own system and then make a decision whether one likes it or not. If the answer is “yes” than LAR amplifier will reward its owner with a quite mellow music presentation. A slight emphasis on lower midrange creates a specific sonic signature, making them sound rich and more powerful. Soundstage is large in terms of both width and depth but since decay is not sustained too long one wouldn't call this presentation extremely spacious. This presentation might be also called euphonious, but in a pleasant way.
And in fact what one has to pay for IA-120H gives one two devices in price of one – a great integrated amplifier and an amazing headphone amp – so in fact one gets one of these amps for free.

Front panel sports characteristic (for the brand) round VU-meters displaying level of input signal driving preamplifier. The same VU-meters were used also in IA-30T and its successor IA-30T MkII. But in fact we saw this design for the first time when we reviewed solid-state IA-120 back in 2004. The preceding model, IA-45 MkII, was equipped with rectangular meters that looked like they'd come from 70ties.
IA-120H is quite a large device – similar in terms of dimensions to IA-30T MkII. The front panel sports two knobs, a volume control and input selector, that offers also second functionality – it is an on/off switch. Not many modern design use this solution – if you turn the knob extremely to the left it turns off power supply. When you do that there is a single orange LED on, on the front panel, and when you switch of the main switch on the back panel also this LED turns off. When you turn the knob on the front to the “off” position (which is stand by) the backlit of VU-meters doesn't shut down immediately and the light dims off slowly – it looks really cool.

There is one more element of the front, that was firstly introduced in improved version of IA-30T: a headphone output. I remember very well when Mr Czyżewski sent me this first version and informed me that as sort of experiment he added a headphone output on the back panel. The standard version wasn't supposed to have one, it was supposed to be only an optional feature. But it turned out that this amplifier was as good integrated as it was headphone amp. The MkII proudly sported headphone out on the front and the same goes for IA-120H.

Typically for LAR back panel seems very orderly: a single speakers posts and two rows of RCA sockets: five unbalanced RCA inputs and one RCA pre-out. There is enough space between sockets so even large plugs shouldn't be a problem. Next to the EIC socket there is a mechanical on/off switch.

This type of products is often described as „dual-mono”. It means that in single casing there are two separate amplifiers for left and right channel. With IA-120H things get a bit more complicated. There are in fact two independent power supplies for the right and left channel. You can find them on PCB's bolted to the side wall of the casing, placed far away from each other, which helps to reduce any magnetic interference. Next to them there are large toroidal transformers, with couple of secondary windings. But the power amplifier itself is placed on one PCB for both channels – so it is not full dual-mono design. Also because preamplifier stage is supplied by a single transformer – a very good one, shielded with copper plate. Signal is amplified by a single double triode - Sovtek 6H30Π-EB. So you can call this design dual-mono but with some reservations and only if you talk about power amplifier section. There is a sort of frame around tube to make sure it safely stays in its place. This double triode is coupled with the next stage with polypropylene capacitors. There is a large Alps pot for volume control.

Power amplifiers use transistors hence the hybrid design of this integrated amplifier. Power stage works in class AB, in push-pull mode, using one complementary pair of transistors per channel, IRFP9240+IRFP240 made by International Rectifier. These are HEXFET MOSFET transistors. These are driven by BD911+BD912 transistors, that are bipolar ones. Transistors are cooled with vertical radiator, although they are not directly bolted to them but rather to additional element that is fixed to the radiators. Individual PCBs are connected with cables that are screwed into sockets. That's a part of Mr Czyżewski's training – safety, reliability, and easiness of servicing come always first. Many audiophile devices look (inside I mean) as a madman's dream – there is chaos instead of order. It still might sound good but it is hardly a finished product. The internal design of Mr Czyżewski's amplifiers is exemplary and others should learn from him.

I have to mention also the high quality of mechanical assembly. There is an internal cage made of aluminum bars that supports the whole casing with a thick aluminum plate screwed to it at the bottom. The power amplifier PCBs are bolted to this plate and not to the amplifier's external bottom plate. Side walls are also doubled with aluminum plates. The external panels are also made of aluminum. It seems that Mr Czyżewski is experimenting with the connection between external walls and internal design. This time he used wood elements and it seemed like a very good idea – wood acts as vibration damping element between aluminum plates.

There is no remote control.