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 נושא ההודעה: Audio Review: AMR AM-777 Integrated Amplifier
הודעהפורסם: 28/05/11 18:11 
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01/09/08 15:14

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AMR AM-777 Integrated Amplifier



AMR AM 777


The name AMR brings back very good memories: In December 2009 Hifimusic.co.il published Aviad’ Barid’s review of the CD-777, Abbingdon Music Research’s (AMR) entry level tubed CD player. Just before Aviad sent it back to the Israeli distributor I borrowed the unit for a private audition at my personal rig. I had a splendid time, enjoying 777s sense of refinement and the realistic soundstage that it projected.

It was mostly due to this positive experience that I was quite excited when the the AM-777 integrated amplifier (CD-777's sibling) arrived at my doorstep for an upcoming review. I was looking forward to my time with the AM-777.
Memories, nostalgia and audio lineage aside, I was also curious about AM-777’s digital input option: as the physical medium of CD is losing ground, more and more CD players succumb to the new trend and add digital input options. In fact, many of audiophile friends make statements about “their last CD player”.
AMR is not unique in offering a digital input option. Other high end equipment makers such as Ayon, Simaudio and Peachtree also offer similar products. Manufacturers differ, however, on the best approach to implement this idea: Whereas some use the legacy S/PDIF interface, others offer USB.
AMR chose USB over S/PDIF, which sparked both curiosity and concern among us. Indeed, our experience with USB audio implementations suggests that this option is not for the faint of heart.
So, how well did the AMR-777 do on our listening tests? How good is the USB option and does it really allow us to forego the often-used external DAC and get on with the music?
Let’s see.


The AM-777



The AM-777's boasts an impressive brushed Aluminum chassis with a decorative engraving of the company's logo on the front panel and top face. Six translucent windows reveal a variety of components, including the 6N1P-EV tube and the red PCB (with the added effect of providing ventilation). When the AM-777 is turned on, you can notice a blueish light glowing through the openings which are protected by transparent plastic. The five large digital buttons at the bottom of the device are used for turning on / off and as volume and source switches. They have a high-quality feel and a rather appealing design chic. All in all, the AM 777 radiates quality in every aspect of its external shape, design, touch and choice of materials.

AMR AM 777AMR AM 777AMR AM 777AMR AM 777


Technically, the AM-777 is a two-stage hyprid amplifier: the first stage is tubed ( 6N1P-EV with a range of replacement options : ECC88, E88CC, 7308, Cca, 6DJ8, 6922, 6N23P-EV ) in SET topology without negative feedback. The second is using transistors that provide the power to drive a variety of speakers.

AMR AM 777


On the left side of the rear panel, next to the USB connector is a pair of XLR connectors. The XLR connection is shared with the first pair of RCA input, so there is a switch for choosing either mode of operation (“Hifi / PRO”). The group of four following RCA pairs is used to connect sources to inputs 1 to 4. Although these are pretty close to one another I have not encountered any difficulty using them.
Next is a pair of Pre - Out ports. Yes, The AM 777 can be used either as an integrated, pre and power (either stereo or mono!). Very convenient indeed!
The speaker terminals are equipped with 5-way binding posts for connecting cables with banana plugs or Spades.

AMR AM 777


On the right side of the rear panel we find an IR link followed by three switches for speaker impedance selector (4 or 8 ohm), the pre-pro switch that enables or disables the Volume Control of the device transforming it from an integrated amp to a power amp only device and the Amplification method switch (normal mode: two stereo channels; Biamp: two mono channels or standard mono-block (one channel mono).
Above the IEC connector to a mains power cord is the power on / off button.

The touch screen remote control, among other things has shutdown and start-up functions. However, keep in mind that one should wait at least several seconds for the soft start of the tube stage. A convenient function for audio reviewers is naming and gain matching for all inputs.
What’s not to like? Well, not much, other than pressing and holding the volume buttons did not change the volume at a convenient enough speed for my taste.

AMR AM 777


Setup


The MBL 1531 CD player, was the main digital source for this review. After trying XLR and RCA connections I settled on the single ended connection. What about the USB connection? At the time of the review, I did not have a USB cable long enough to reach my HTPC. Thus, my digital source was DELL XPS 16 laptop, with which I already did have some experience during previous DAC reviews. In general, I found that even if did not quite measure up to my HTPC performance-wise, it got very close. Playback was handed to my loyal Album Player software configured to ASIO using ASIO4ALL. Despite complaints about it not being a " real " ASIO driver, I noticed more than once that it provided an improvement to Microsoft's "direct sound" alternative. In fact, even in comparison to the designated hiFace unit it had nothing to be ashamed of (but more on that in another review).

The USB cable I used was a simple printer USB cable, the interconnect which I used for connecting the CDP was an entry level Siltech. Speaker cable were the Crystal Cables Ultras. Speakers were my trusted WLM La-Scala. I figured their higher than usual impedance and sensitivity (8ohm and 93db, respectively) should not have posed any problems for the AM-777. It turned out to be quite accurate.

AMR AM 777


Sound


Dee Dee Bridgewater - Live at Yoshi's
Prior to Ms. Bridgewater's visit to Israel I thought it would be nice to include this album in the review (I guess by the time this review will be published the performance will have been well behind us ).

Dee Dee, renowned for her Scatting abilities (be ba bop bop bo bo right? ) uses them generously for most of the album that covers her performance at Yoshi's Club in California. Although I do not pretend to being quite fond of the charms of Scatting. Bridgewater’s colorful personality, the jokes with the audience and the good sound quality overcome this obstacle for me. Also, The album's overall sound is on the lively side without being too bright or shrilling.


In my opinion the AM-777 did a fantastic job at rendering this album: Ms. Bridgewater's voice was clear, greater than an unamplified performance but not huge and fuzzy. The 777 managed to portray the experience of a live performance, by not being too slow or too lazy. For example, one of the tracks includes a remark by Dee Dee that she loves the tambourine's sound. The AM-777 let them sound immediate and correct but not overly aggressive or fast as some other amps have (The Electrocompaniet ECI 5 or Plinius Hiato comes to mind here).

The accompaniment of drums, piano (sometimes an organ ) and bass were laid spaciously in a three-dimensional space - not a huge stage, but certainly one that is appropriate for a small ensemble. I was quite satisfied with the low frequency reproduction. I like the lack of mid bass blowing out of proportion but missed the tight grip of a much more powerful amplifier such as my own MBL 8011s, which results in a very natural tone. The piano sounded a bit in the back, and I'd love to get a bit more slam out of it, but that's pretty much digging for the faults.

Ry Cooder - Into The Purple Valley
This special 1972 album is definitely not a reference level recording (and that's an understatement), but it is an excellent case study for testing a product that does not adhere to extensive sonic manipulations. Could the AM-777 capture the essence of the music from such an album? The sonic result that was somewhat forgiving, at least partly due to minor sins of omission. I felt that the AM- 777 did not reveal all the negative artifacts hidden in the recording which are easily exposed by the MBL set. Here I would not mind a little more bass, the album is a bit scrimpy in this region - however with " Hey, Porter " (by Cash) I hear that the 777 can bring the WLM low enough in this region. All in all, I liked the sonic result.

Hayehudim - Forte
This album was never on Heavy Rotation at my place. Twelve years ago, when it first came out I already felt too old for it. But I thought I'll pay my respects to Kooke, a well liked HIFIMUSIC’ member by letting him know that the AM-777 did a fine job at reproducing this album. This is of particular significance given that my speakers are probably not the top choice for hard rock albums such as this. I was already used to the wonderful reproduction of percussion instruments. But here I was able to get a sense of the AM-777 ability to render a more compressed,intense type of music without lack of separation or tonal collapses. Lead singers vocals appeared discrete, even when cacophony surrounded them. The lower octaves were produced adequately, but not spectacularly. I felt that AM-777’s focus on the mids was one important factor in its ability to rise to the challenge posed by this particular album.
But let's put things in perspective for a second. Moreover, I felt any perceived dynamic limitations were more associated with my speaker than with any of AM-777’s limitations.
Is the AM-777 a perfect head bangers amp? Of course not: I'm sure there are much more aggressive amps by nature that will do a better job here. However, if hard rock is only a part of one’s musical diet, I think you will not be disappointed by its performance in this region.


Hans Theessink - Songs From The Southland
A Dutchman singing the blues? Hans was born in the Netherlands but now lives in Austria. Given that I was introduced to his music in one of the Munich High-End shows (Diana Krall, anyone?) it's no coincidence that his albums are of the “Audiophile” breed. At least in this case, I do not mean it as a compliment.

Hans performs his penetrating songs in low voice with an excellent English accent. This album gives us 14 roots music performances he claims to have learned from masters in the field, and these tracks accompany his performances for many years.

The recording, although not a “purist” one, is of high audiophile quality, where the microphone was placed in close proximity to the singer and the instruments. Hans played the harmonica and all the string instruments except bass. Although this means, of course, that the mixing stage included over dubbing, it did not diminish the sonic result. The 777 managed to externalize the silent passages on the recording in a manner that greatly surprised me. String instruments (guitars, banjo, mandolin, etc') sounded detailed, realistic and, in general, tonally correct. Hans's voice is large and deep, very natural and pleasant without any dreaded solid state artifacts. Backup female singers are located at the rear without any loss of separation or added coloration.

This album presented the AM 777 as a component allowing an abundance of finesse, tonal correctness and three-dimensional rendering. Again, it did not come across as being too aggressive or too hi-fi. In my opinion the AM-777 was very much at ease with such an acoustic recordings.

Anat Fort - Peel
On the pre-ECM “Peel” Anat playing is less dramatic than the "A Long Story" album. The AM-777 managed to reproduce the recording with (what I came to appreciate as) typical serenity. As before, percussion instruments were outstanding in every way and the bass had weight and depth. I was, however, quite disappointed by the rendering the piano, Anat’s own instrument. Trying to analyse this, I realized that I was really pleased with the higher and lower octaves but found the middle octaves to be somehow compressed. That odd, though: A tube incorporated integrated amplifier having problems in the midrange? Well, sort of, but let’s not get too carried away here: I rather liked the balanced tonal direction of the AM-777. But contrary to what I'm used to getting from all tube components it lacked that midrange blossom. Even if at first it bothered me a little (mostly because it was unpredictable and I was caught unprepared, I guess) I was soon able to really enjoy and the AM-777’s accurate imaging, it’s wonderful musicality and sense of tonality.

Using the USB input


AMR AM 777


Contrary to more modern asynchronous USB audio implementations, AM-777’s USB implementation is limited to 16 bits and a sample rate of up to 48kHz only. Did it impact the sonic result? In general, I found the USB input much less dramatic and " quiet " than the CDP. There was clearly a sense of less bass and a result that was too soft to my liking.

Allen Toussaint - The Bright Missisipi
I won’t go into much detail about this recording as it was included in several previous HIFIMUSIC reviews. Using the AM-777’s USB input, I felt that the computer input did a nice job, but didn't really approach the level of the CD transport. You definitely got the essence of the experience and the music: as usual, the pace was relaxed and not aggressive. But overall, it felt less dramatic, probably due to a sense that it had less of a "black" background. I will elaborate on my conclusions about the USB input in the summary.

Summary


Not long ago, our HIFIMUSIC forum engaged in a lively discussion on the influence of a reviewer's personal taste on the results of the review. Recently I had a chance to meet several novice audiophiles. I found that most of them shared a fascination with low frequency information, detail and stereo image size. My guess is, that the AM-777 is not the best match for them: it does not highlight details and does not go out of its way to amaze you. But this perceived indifferent attitude goes a long way towards winning you over in the long run.

I found the AM 777 to be very compatible with my personal visual and sonic preferences. It portrays first class musicality, while at the same time projecting a very realistic soundstage. The AM-777 provides a sense of refinement and finesse that is only rarely found in its price class.
Last but not least, some final musings on the USB input.
The obvious question is " Is it enough"? In other words, can you just plug it in, sit back and enjoy the ride? My answer is that with a properly configured computer one can achieve very nice results without having to invest more in a source component. On the other hand, a head to head comparison with my CDP convinced me that this amp could be a much more capable performer if one uses another digital source. I view the use of the AMR-777s USB input as an intermediate stage for those who are eager to get into a computer-based system.

In conclusion, I absolutely loved the AM-777. It is the perfect budget-oriented accompaniment to owners of speakers with average to higher-than-average sensitivity who value finesse and tonal balance above all. It may not be a good choice for the hard rockers among us, who will have to look elsewhere. With such a strong performance, I am now curious more than ever about AMR’s upscale models.

AMR AM 777


Many thanks to our friends: "Giant Steps" and Noam for their tremendous help with the English translation.

Technical Data

Power:
60 watts per channel at 4 or 8 ohm ( stereo mode )
70 watts per channel at 8 ohm ( monoblock mode )
120 watts per channel at 2 or 4 ohm ( monoblock mode )
Output impedance: 0.33 ohm, 20 - 20,000 Hz
Signal to noise ratio: greater than 100dB
Total harmonic distortion + noise: Less than 0.3%
Dimensions: Width 45 cm Height 12 cm Depth 37 cm
Weight: 14 kg


Review and comparison Set up

Source: MBL 1531
Amplification: MBL 8011S, MBL 5011
Cabling - Power: ELROD & MBL
Cabling - Signal: Siltech New York, Siltech SQ110, Crystal Cables Ultra \ Dream
Rack: Finite Elemente Pagode Master Reference
Speakers: WLM La-Scala

Price: 18,500 NIS
Importer: Arama Audio

_________________
ביוגרפיות , עם קלאסי ואלגנטי , פשוט לא הולכים לעבוד.
I have been supported from the bottom of my heart
בוכה דה פלורסנט


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