EASTERN ELECTRIC M156 TUBE MONOBLOCK AMPLIFIERS
PRICE: $5,0000 per pair

Review by

James L. Darby

&

Vincent Caponi


The Eastern Electric M156 is a monoblock power amplifier, meaning that each amplifier is monophonic and therefore two are needed for a stereo system. Designed by Alex Yeung and made in China, each amp delivers a massive 160 watts and consists of a tube compliment of four Shuguang (re-labled as Eastern Electric) EL-156’s and two 12AU7’s. If you are a tube aficionado, you may be asking yourself what the devil is an EL-156. We’ll talk more about that in a second, but as far as I know, this is the only power amp that uses them, so we’re looking at a pretty unique product here.


At 56 pounds each, the amps are built and finished immaculately in a dark gray case that extends back over about a third of the chassis, hiding the massive transformers but leaving the tubes revealed. The front panel is a silver brushed metal that has few simple controls and one big, BMW dashboard style orange power meter that doubles as a biasing indicator. A knob on the upper right switches between five detents – one for biasing each EL 156 and the center position which engages the power meter function. A switch on the bottom right toggles between “Bias Current” and “Output Power”.

Biasing is easy and painless. Simply flip the knob to “V1” and use a small screwdriver in the corresponding set screws below to position the meter over the number 40 on the lower scale. Repeat for V2 through V4 on each amp and you’re done. There is also a button on the front that powers each amp on and off with a pale blue light that indicates when the amp is on. It’s a bit redundant since the power meters are only on when the power is on – they cannot be extinguished. Fortunately, they are not so bright as to illuminate a darkened room so there is no need to turn them off.

 


Around back there are high quality terminals that allow you to choose between either 4, 8 or 16 ohms, depending on your speakers. Most amps only include a choice of two such as 4 & 8, so kudos to Alex for giving us a better opportunity to more precisely match the amp to a wide variety of speakers. In addition, there are inputs for either standard unbalanced RCA’s or balanced via XLR’s. We are even given the choice between US and EU wiring of the XLR’s hot pins via a toggle. Finally, while a hefty power cable is included, since it is not captive, any upgraded power cable can be used.


We would like to thank Bill O'Connell of Morningstar Audio, North American distributor for Eastern Electric for providing us with the review samples and working with us so graciously on this review. Bill has a real passion for music and audio that was very apparent in my conversations with him. Bill and Morningstar sell the M156 as well as the rest of Eastern Electric’s extensive line of audio components direct, providing a significant cost savings to buyers since there is no additional dealer markup.

 

THE EL-156 TUBE


As mentioned above, the EL-156 tube is unique and a recent addition to the universe of glowing glass. The EL 156 is not technically new, but rather it is a resurrection of a tube that died – went out of production - in the 1970’s. Mr. Yeung told me that the EL156 was designed specifically for audio signals by Telefunken in the late 60’s. It may surprise some of you that many tubes used today in stereo equipment were not originally designed for that purpose. Some were designed to be used in radio broadcast transmission, manufacturing machinery and many were used in military gear – including radar and airplanes – applications that were not specifically for reproducing music.


According to Yeung, “This tube is so linear and accurate that it was often used for master recording. Most of the popular power tubes were beam tetrodes like KT88 for example. The EL34 and EL84 are probably the two most popular pentodes. EL156 was made as pentode with plate dissipation of 50W which was the highest power indirect heated pentode. Note the plate dissipation of EL34 was 25W and KT88 was only 42W. EL156’s 50W plate dissipation was really a record. Unfortunately they stopped production of this tube in the 70s. The tooling were then transferred to a tube factory in China and China continues the production of this great tube. The bottle and the structure are basically the same as the original German EL156, except that the Chinese manufacturer has changed to use the most common octal base”.


The “octal” base Alex refers to means the 8 pins that virtually all modern amplifier tube sockets use. The original Telefunken had 10 pins.
Alex continued, “The greatest pentodes ever produced in the era of tube components were probably the EL156 tube and the F2A11. If any tube manufacturer ever starts up production on the F2A11, we will probably build amps around it ,but until that day the EL156 will suffice. The input/driving stage is very similar to the Williamson which has very low distortion and very good driving power for the output stage. The output stage is a basic parallel push-pull with the 2 pairs of EL156 connected in pentode mode which is the best sounding configuration to my ears”.

 

We really put these amplifiers through the wringer for this review. Not only did I use them extensively in my own system, but they were additionally evaluated in two very different rooms and systems. We even had a four-person listening session in friend and dealer Al Helo’s home with his giant mega-buck Acapella Triolon Excaliber horn speakers (pictured above) with plasma tweeters and two bass towers that each contain four 15” woofers. Each speakers weighs 1,364 pounds! The amps you see in the picture are all Einstein. His table is a Galibier with Schroeder and Triplanar arms with an assortment of high-end cartridges. A Stereomojo Second Opinion separate review by our Vincent Caponi follows.

 


As you know, normally when eight people listen to any given component, you will get eight differing opinions. Amazingly, in this case there was unanimous agreement on the sound of the Eastern Electric M156’s, so rather than prattling on with endless quotes, let’s save some time by condensing the observations.


First, let’s take a look a closer look at the Acapella/Einstein system:


Source 1: Einstein The Source balanced tube CD player
Source 2: Galibier turntable, Schroeder & Tri-Planar tonearms
PreAmp: Einstein The Tube mkII
Amp: Einstein The Final Cut balanced OTL tube mono amplifiers
Speakers: Acapella Triolon Excaliber
Cables: Acapella High LaMusika
Phono Stage: Einstein The Turntables Choice (balanced)
Phono Cart.: Einstein, Dynavector, ZYX, VDH
Stands & Racks: Custom Design
Platforms: Acapella Fondato Silenzio Bases
Powerlines: Isoclean (complete system)
Accessories: Isoclean, Millennium
Room Size: 24'W. 30'L. 14-20'H.

It is fair and even compulsory to point out that each of the very fine Einstein components listed above costs more – even several times more - than the $5,000 combined pair of Eastern electric M156’s. For example, the Einstein Final Cut monoblocks alone cost almost $22,000 per pair, even though they put out only 20 watts each. The 156’s replaced four of them in our evaluation. The preamp, which we also used for the M156’s, goes for $15,700.


The group of four guys and two gals first listened to the system as is via two LP’s and two CD’s – one being the Stereomojo Stereo Evaluation CD which is programmed with 12 various musical cuts, each of which tests various qualities such as soundstage, speed, transparency, complexity, dynamics, orchestra, jazz, rock, male and female vocals and so on. Then we substituted the M156’s for the Einstein's and listened to the same material. We had all heard the Acapella/Einstein system many times before in other listening sessions on other evenings, so we were all familiar with it. Needless to say, the sound is immense, articulate, pristine and very musical. In a word, incredible.


As big and beefy as they are, I must say that sitting in front of that huge system in that big room, the 156’s looked almost tiny. You can barely see them in the picture. I think everyone was expecting a significant drop off in sound quality when we plugged them in. And at first, there was. In a word, they sounded bad, especially in the low end. Congested and rather anemic. I reminded everyone that the amps were cold and needed a good 30 minutes to warm up, so we all adjourned to other parts of the house while the amps cooked. Still, this was a significant observation. Since they have no standby mode to keep minimal current supplied to the tubes, every start-up is from a cold state, so a warm-up period is mandatory. In my system, the amps did not sound as ragged as they did initially that night, though. Apparently the strain of powering those big horns, even though they are efficient, and those eight 15” subwoofers made power up a little more traumatic.


When we all reconvened and cued up the Stereomojo Evaluation CD, things were much, much different. After plowing through most of the examples, everyone (including me) was surprised at how good they sounded compared to the Einstein's in this ultra-revealing system. The big horns and bass cabinets still disappeared leaving a huge soundstage that extended from side to side across the 30’ width and up to the 20’ ceiling. No shrinkage at all. There was still plenty of detail throughout the audio spectrum and nothing was lost in translation. Depth and layering were about equal. No veiling was introduced. Vocals had the same warmth and presence and dynamics were equal if not a bit better on really big drums and orchestral crescendos. The top end did not suffer roll off and had close to the same amount of sparkle and transient response, but perhaps not quite as much speed. The Acapella’s plasma tweeters, which do not use conventional cones but a field of gas to reproduce upper frequencies, are the fastest in the industry. An amplifier that is slow would be exposed immediately. It didn’t happened.


One area actually was noticeably superior and that was the low end as produced by the big bass towers. There was more grip and control and an overall firmness that even the owner a bit begrudgingly recognized. In fact, here is a direct quote by Al Helo whose home and system we enjoyed that night: “Long warm up time. Once warm these bad boys are excellent.Open, plenty of power, no bloat, very good bass, very nice mids and extended open high end. No over blown tube sound, but does retain the smoothness of tube amps. Not the sterile, etched sound as in solid state. They have that bloom in the mids that I like in tube amps. The sound unfolds and blooms from a very black background. Not as fast as OTL's (his Einstein’s) but what is! Strong controlled bass. These amps would definitely be on a list to hear if I was in the market. Considering price these amps should be a contender on anyone’s list”.


Factors where the Einstein’s were superior were the space between the notes and less grain in the ambient cues. Solo instruments and voices as well as individual notes in orchestras and smaller ensembles were isolated more nothingness around them. All the details were there with the 156’s, they were just easier to hear with the Einstein’s. Reverb, whether artificially studio induced or naturally captured in a venue, was cleaner and more transparent and seemed to hang in the air a bit longer. Overall, every listener said how impressed they were by the “little” Eastern Electric’s. I was asked several times how much they cost, as if the panel found it difficult to believe.


As part of reviews of two other speakers, we hooked up a pair of the British Cygnis floorstanders by Revolver and the new planar .5 by Podium, both driven by the M156’s. Nobody’s opinion of the amps changed in those evaluations.


The observations made by the panel coincided exactly with conclusions at which I had arrived in my own system, which were pretty much what designer Yeung told me after all evaluations were complete: “These are not your typical lush, over the top, rolled off tube amps of old, they are dynamic, extended, controlled, grip the bottom end instruments that reproduce the signal that is fed into them.”

 

 

 

Eastern Electric M156 Mono Block Power Amplifiers
Review by Vincent Caponi

Other equipment used with this review


Eastern Electric Minimax preamp (modded)
Minimax phono stage
JA Michell Tecnodec/Denon DL-103R cartridge
Minimax CD Player
Silverline Prelude loudspeakers (version 2).

The Eastern Electric M156 mono block power amplifiers are the first high power tube amps that I've had the opportunity to audition in my home. What immediately struck me was that I could feel much more emotion and excitement in the music. The M156 mono blocks reproduce music with a smooth response, clean natural tone, with a fullness and authority in the bottom end that I had not experienced while listening to lower powered amplifiers. Even at lower volume levels it seems that the headroom provided by the hefty power reserve produced a wonderfully deep bottom end in an effortless manner, which greatly contributed to my feeling of involvement in a true musical experience.


My listening experience over the years has lead me to the school which believes that vinyl is a much better medium for pleasing music reproduction, as compared to digital sources. I played many compact discs early in my audition of the M156 mono blocks, but with a more casual attitude than vinyl, and at somewhat lower volumes as I tend to experience listening fatigue during extended periods of playing them too loud. Therefore I was pretty much prepared to focus my more serious listening on the analog source. But as I turned up the volume on a few compact discs I began to find that many sounded exceptional through the M156 mono blocks (others just about as awful as always). I was compelled to begin listening to the compact discs more critically, and was surprised to find so many that pleased me in the process, even at louder volume levels.


The details of my listening experience? Again, tremendous bottom end here, powerful bass but very well controlled. But that is just one of the qualities that contribute to the success of the M156 mono blocks. The high frequencies are presented with wonderful detail and clarity. Very precise while still retaining a beautiful musical presence. Mid range was smooth with a wonderfully rich tone.


 

The Classic Records pressing of Ella Fitzgerald's, "Let No Man Write My Epitaph" is a good example to describe what I heard in terms of the vocals. Ms. Fitzgerald's voice had that familiar airy tone that I enjoy so much about her singing with a beautiful sense of space surrounding her. Her vocals were very smooth and presented in a much more natural tone, with just a hint of air, and I thought to myself, now that's how she's supposed to sound! Beautiful warm tone without a touch of grain.


 

 

Mark Knopfler's naturally warm vocals on Shangri-La were reproduced in a similarly less colored manner. Of course it's a matter of preference, but since my musical taste leans towards small piece instrumental jazz bands and vocals, I think I would be happier with the stocks.


Some other very enjoyable listening sessions: An excellent original Phillips LP recording of C.S. Bach piano concertos revealed wonderful detail through the mono blocks, especially noted in the solos.


 

 

Johnny Hodges, "Blues A Plenty" had an excitement, realism and energy that I hadn't known before. The clarinet on the Hodges LP had a wonderfully natural woodwind tone, and Johnny's saxophone work could nearly send chills down my spine.

This and many of the smaller jazz band recordings particularly revealed wonderful imaging. Each instrument seemed to have it's own space, and the result is a very nice soundstage in regard to both width and depth.


 

Louis Armstrong and Duke Ellington, the Classic Records pressing, is fantastic in it's realism. Julian Adderley and Bill Evans "Know What I Mean" never sounded so fine. The detail in Mr. Evans piano is delightful, and the tone of Cannonball's alto sax is presented beautifully.

Duke Ellington "Blues In Orbit" is a wonderful CD. Very smooth response that sometimes I am nearly fooled into thinking that I have a record playing. On the M156 it was even more enjoyable.


Jorma Kaukonen's "Blue Country Heart" on CD presented the various acoustic instruments with both sparkle, warmth and cunning realism. With the tremendous headroom of the M156, Pink Floyd's "Meddle" LP sounded amazing. On "Fearless", a song which has sections that build from quiet to large and full, the dynamic range was fantastic.


Another CD that was handled remarkably well is Jamie Cullum "Twenty Something". The energy and life in the title track is nothing less than thrilling, as is the jazz standard, "I Get a Kick Out of You".


 

 

 

 

Finally, the MFSL LP pressing of Alison Kraus & Union Station, "So Long So Wrong". Well, one need not use words to describe the brilliance of that recording in general. The M156 impeccably supported all of the wonderful qualities of the LP. Absolutely breathtaking through the M156 mono blocks.


As I continued to listen in various sessions, the thought that I was hearing recorded music drifted further back in my mind. Those feelings were replaced by a growing sense that I was becoming more a part of the true music. Prior to this audition, given my listening style of typically lower to moderate volume levels, I was asking myself the question, "Who needs that much power? I probably don't use more than a few of the 20wpc with my current integrated amplifier". But a taste of the M156 has answered that question for me. I would have never imagined a more emotionally moving musical experience, yes even with just the first few watts of these wonderful amplifiers.


 

Now that brings us to a close with my girlfriend's impressions. Angela is not an audiophile. As a matter of fact, when we met nearly three years ago, I used to ask her as we listened if she could hear a particular quality in the music. She would kind of give me a puzzled look, and even admitted that she really couldn't hear much of a difference between an ipod and my M520 system (a beautiful integrated amp by the way, that I enjoy immensely). I guess all those Sunday nights of listening to music on a quality system has gradually made her more sensitive to how good music really should sound.
From the first record that I spun for her on the M156 amps, she very quickly began to express hearing subtle details in the music that she hadn't heard before. She thought the mono blocks sounded "wonderful", "more real", "like the musicians are here playing here in the room with us". Of course, she also was very impressed (as was I of her observations). I'll end this write up with something that Angela said that I neglected: They are so cool to look at too, especially once you shut the lights and just enjoy the music! In her words, "They are so pretty!”"

Publisher's note - Vincent purchased the M156 amplifiers after completing his review. In addition, there is a factory upgrade of Mundorf Silver and Oil Capacitors said to add detail for an additional $700 each.

 

 

 

Whew. We have had an unusual series of reviews of components that have turned out to be rather positive. Does that mean we've changed our review process or philosophy? No. It just means that we have had some pretty good products come our way lately. I don't think it is any surprise that in this competitive environment and with huge advances in technology that the majority of audio products on the market today are superior and often less costly than those in just the recent past. We still and always will "call them as they truly are". Bear in mind that NO audio product is perfect, appropriate or even "good" for everyone. An amp or speaker that might be great for one person in one system and one room may be awful in another. That's why we have SPECIFIC recommendations, and sometimes the recommendation can be "NOT Recommended".

The Eastern Electric M156 Monoblock tube amplifiers were put through an unusual gauntlet of evaluations because we determined early on that they appeared to be an unusual product. By every standard, the amps proved themselves to have a very high level of audio performance at any price and an extraordinary level at their current price - and opinion shared by at least 6 individuals in several different rooms and systems. Are the M156'sappropriate for everyone? Of course not. Nothing is.

First, there are many people who prefer the sound of solid state or whose systems (speakers mainly) sound better to them via solid state. Many people also don't want to fool with tube biasing and the eventual degradation that takes place as tubes age and need to be replaced. Tube amps put out more heat than solid states, especially Class D amps. While it's possible these amps could change some minds, solid state devotees are probably not good candidates. In addition, monoblocks of any type take up more room than either integrated amps or even a separate stereo power amp. Those with limited space won't want these no matter how good they sound. You cannot stack these. Of course, you'll still need a preamp which is an additional cost. More cables,too. If the rest of your system is on the lower priced (and quality) level, five grand might be too many bucks to invest.

Some people do not like power meters.That would be a deal breaker for them. If you have extremely efficient speakers, say 95 db or better, in a small room, you may feel you don't need 160 watts per channel.

So who might find these monoblocks attractive? Those who have larger, more expensive systems who would like to see if tubes would make a big difference in their listening enjoyment would be excellent candidates for the Eastern Electric M 156's.Even if you have auditioned tube amps before and found them too soft or rolled off in the highs and lows, giving these a listen would probably change your mind. The EL 156 tubes used here do not suffer from that like the 300B, KT88 and so forth. They are different. Anyone who is thinking of upgrading their tube power amp or amps seeking better sound and/or more power should definitely try these. We at Stereomojo value value, and these represent an outstanding bang for the buck.

 

If interested, contact information is here.

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