Review: Sony MZ-R 90/91

Sony MZ-R 90

This will be my last review of a personal MD recorder for the time being. I´ve received several complaints from personal friends of mine that I concentrate too much on ancient or obsolete technology. Since I also want to talk about other stuff ('snake oil' for example) I´ve finally decided that I have bought enough used MiniDisc recorders and that it´s time for different things. The next article will be about ATRAC, it´ll also contain a guide to hack the firmware of two MD recorders - that´ll be it. On with the review now, shall we? Just like the MZ-R 37 I bought this one not because I wanted it but because I was bored. I placed a bid, being confident that I wouldn´t be successful only to find out later that I´d won the auction. At first I became quite aggravated with myself for buying an MD recorder I never wanted to own in the first place but after it arrived I felt very lucky indeed... boy, this thing is a beauty! Released in 1999 it sports a fantastic manufacturing quality: everything fits perfectly, its shell feels extremely sturdy and is delightful to touch.

Sony MZ-R 90 close-up

But once it starts to play or to record a MiniDisc the impression of high quality is diminished quite a bit: the drive is extremely loud, it literally seems to be 'grinding' along while the disc is spinning. It´s so loud that I can hear this unnerving noise easily during soft passages when playing music over my Sennheiser HD-448. Furthermore, the drive mechanism behaves extremely sluggish: in an effort to conserve battery power Sony chose to implement an aggressive power saving strategy which occasionally results in a waiting time as long as five seconds - and that´s only for a track change. The successor MZ-R 900 is a lot faster but still not as fast as the MZ-R 55. The MZ-R 90/91 also is the first recorder to lack a seperate line-out - it has been combined with the headphone output and can be configured via the menu. It´s a bit smaller than the MZ-R 55 and does seem to have a higher level of integration for some ICs. The ATRAC IC is a CXD-2660GA which uses version 4.0 or 4.5 (measurments are inconclusive) of Sony's proprietary codec, it also seems to combine several ICs into one. Apart from that some things (the DAC for example) have been left unchanged, they are the same on the MZ-R 55, MZ-R 37 and the MZ-R 90/91. The drive and its laser have been completely redesigned compared to the two former models - both are much smaller and also much slower. When I first listened to it I immediately noticed that it sounds much crisper than the aformentionend units, in fact its crispness appears to be a bit too much. I suspected jitter so let´s have a look at my measurments:

Sony MZ-R 90/91 measurments, line-out activated

Sony MZ-R 90/91 measurments, headphone output activated

Sony MZ-R 90/91 jitter

ATRAC measurments, 24 bit input: ATRAC 4.0 or 4.5?
Dynamic Range & IMD are like ATRAC 4.5, THD is like ATRAC 4.0

My suspicions were wrong because as you can see jitter isn´t the culprit here; while it might be audible I think that it isn´t the main problem of the MZ-R 90. Much more serious are high frequency distortions over the analogue output, not even the MZ-R 37 distorts that much. Total harmonic distortions are 10 dB higher, intermodulation distortions are four times as high. BTW, measurments don´t change, no matter how the output is configured which means that the line-out function is nothing more than setting the volume to max and switching of AVLS and MegaBass (the MZ-R 900 has a real line-out setting, changing voltage levels). Another word about the jitter performance: isn´t it amazing that it differs so much from the measurments I did for the MZ-R 55 and MZ-R 37? All three use exactly the same DAC (AK4517) so in laymans' terms they all should have the same performance. Instead, these differences prove that the overall PCB layout is much more important than the DAC-IC itself.

Sony MZ-R 90

I´ve already told you that it sounds very crisp. On some recordings this is nice but on others it adds an aggressiveness not very suitable for well rendered sound quality. While it doesn´t distort as much as the Sansa Clip+ it nevertheless shares some of its sonic traits: dynamics are a tad too explosive and contrived, stage congested, the sound sometimes lacks warmth. Apart from that its sound is ok; stage is much flatter than the reference but equally wide, leaving enough space between instruments. Overall articulation is ok, albeit a bit artificial, the resolution walks a fine line between slightly exaggerated brightness and edginess. Despite its brighter-than-necessary sound the details are rendered too casually, high frequency definition on occasion dissolves into noise. Timing is ok but nothing to be mad about; it´s slower over the whole frequency band which results in missing snap and punch, the aggressiveness doesn´t help. I have to say that I´m disappointed by its sound; for some recordings it might be helpful but for most available releases it´ll be too much because it sounds too forward. Mediocre, predecessor and successor both are the superior units.

Sonic Balance:

Dynamics:

Resolution:

Stage / Ambiance:

Character:

Sony MZ-R 90: perfect built quality

Sony MZ-R 90 close-up

Review: Sony MZ-R 37

Finally: you´re about to read the last out of nine reviews. You still don´t need to read them all, just pick the unit that seems to be the most interesting to you. During the last few weeks I´ve reviewed the following units: Kenwood DP-5090, Pioneer DV-610, Sony CDP-470, Pioneer BDP-140, iRiver IMP-550, Sony MZ-R 55, Sony MZ-R 37, Sony NW-A 1000 and the Sansa Clip+. Stay tuned and enjoy the last review: the Sony MZ-R 37! I also implore you to read the article describing my rigorous testing methodology before you actually start reading this one.

Sony MZ-R 37

Yay!! President Barack Obama has been re-elected one hour ago (at the time of writing)... I can´t tell you how really happy I am for the American people. What better opportunity to celebrate this marvellous win with the last review, the Sony MZ-R 37? This awkward looking MiniDisc recorder was released in 1999, roughly half a year after the Sony MZ-R 55. - both however contain 90% of the same ICs. A/D-/D/A converter, ATRAC, RF amp, DC converter, System Control IC, Laser and drive mechanism are exactly the same. The amp for the line-out/headphones however is different, the MZ-R 37 apparently uses a slightly more recent IC. However, all parts have much more available space compared to the MZ-R 55, they are evenly distributed on the PCB and not so tightly packed. Both are equipped with exactly the same drive, it is clearly stated in the service manual that the MZ-R 37 inherited the fast, noisefree and reliable drive from the MZ-R 55. All of this might not interest you but you´ll find out soon enough why it´ll be important.

Sony MZ-R 37 close-up

To be honest... I never wanted to own this unit, I acquired it by accident only. It usually sells for roughly 35,- to 70,- Euros on eBay depending on its condition; so I placed a bid of just 15,- Euros. I had nothing else to do, was bored and also convinced that I´d never get it. In the end I forgot all about it. Hence my surprise: many hours later when I checked my mails I became aware that I was the winning bidder and that I also payed only 12,- Euros for a MiniDisc recorder which - when it arrived - I found to be in pristine condition. As you can see on the photos there aren´t any scratches, blemishes or dents, it really looks like new. How incredibly stupid of me never actually considering this lovely recorder because upon the touch it feels really decent, manufacturing quality is excellent. Yes, it´s lighter and bigger than the MZ-R 55 but nonetheless everything fits nicely, feels great and sturdy. Featurewise both of them aren´t that different - the MZ-R 37 only misses an internal clock, meaning it doesn´t stamp the date of the recording onto the MiniDisc. The MZ-R 37 also has the peculiar destinction of being the last portable MiniDisc recorder sporting a seperate Line-out, all others that came after either had none or combined it with the headphone output.

Sony MZ-R 37 front

Sony MZ-R 37 measurments

Sony MZ-R 37 jitter

Now you see why it´s important that I mentioned the similarities to the MZ-R 55: they measure differently despite containing the same ICs. Jitter for example is much higher on the MZ-R 37... which is very curious when keeping in mind that both feature the same A/D-D/A converter (AK4517), subsequently they should have the same amount of jitter. With the MZ-R 55 jitter probably won´t be audible, with the MZ-R 37 however it will: low frequency jitter reaches levels of -80 dB which might be responsible for its characteristic sound signature. Total Harmonic Distortions are higher as well: -71.4 dB (MZ-R 55) vs. -64.3 dB (MZ-R 37). Both of them are equipped with the same ATRAC 4.0 chip, enabling recordings featuring a bit-depth of 24 Bit through their digital inputs. Analogue recording and playback through their own converter however will yield only 16 Bit performance (even less if you consider the mediocre noise performance). Back to the point: will the measurment differences also lead to audible differences?

Sony MZ-R 37 die-cast drive: extremely reliable; also used in the MZ-R 50, MZ-R 55

The Sony MZ-R 37 does indeed sound different, it really isn´t a balanced recorder. Stage for example seems rather compact and full of depth on the MZ-R 55 whereas the MZ-R 37 manages the rare feat to keep the mindboggling depth while also widening the stage considerably. The MZ-R 37 doesn´t sound close to the reference, it creates more space between instruments instead, recording venues sound much bigger albeit dimly lit. Vocalists (or everything in the center) are pronounced as well, I´m able to make out Madonna more easily, it seems as if she takes an additional step towards the microphone while everything else is placed a bit further behind. It´s interesting: this is only the second gadget I´ve reviewed that does sound forward without sounding aggressive. The marvellous stage and ambience performance is indeed its most appealing sonic characteristic; even though it occasionally creates disadvantages because on already very wide sounding recordings the MZ-R 37 punches 'holes' into the virtual stage which sometimes sounds odd and a bit 'empty'. It combines this with lovely dynamic capabilities: speed, pace and rhythm are a bit faster than the original, timing is rendered exceptionally well throughout all frequencies. The Sony MZ-R 37 is one of the rare units (like the Sony D-335) that doesn´t represent the truth but exchanges it with its own, convincing character, it 'lies' so well that you won´t recognize it most of the time.
But when something is exaggerated another things suffers: the track from "The Girl with the Dragon Tattoo" sounds much too mellow, it looses its aggressive treble, lower frequencies are unintelligable and muddied. Deep bass is diminished as well, the same goes for treble. Transients are too lovely, avoiding a grungy or aggressive sound. Additionally, you won´t exactly marvel at resolution and precision with the MZ-R 37, details are rendered too casually for that. Despite these shortcomings this is one of the most appealing MiniDisc recorders (and one of the best 'interpreting' audio units) I´ve ever heard.

Sonic Balance:

Dynamics:

Resolution:

Stage / Ambiance:

Character:

Sony MZ-R 37: bottom

Review: iRiver IMP-550

You´re about to read the third out of nine reviews. You don´t need to read them all, just pick the unit that seems to be the most interesting to you. In the weeks to follow I´ll review the following units: Kenwood DP-5090, Pioneer DV-610, Sony CDP-470, Pioneer BDP-140, iRiver IMP-550, Sony MZ-R 55, Sony MZ-R 37, Sony NW-A 1000 and the Sansa Clip+. Stay tuned and enjoy the third review: the iRiver IMP-550! I also implore you to read the article describing my rigorous testing methodology before you actually start reading this one.

iRiver IMP-550

Back in 2003 when portable CD players started a second (but brief) life as mp3 players a small company named iRiver rose to prominence and became the darling of PC magazines journalists and geeks alike. They combined a spectacular number of features (even unnecessary ones) with supposedly great sound and a superior manufacturing quality. The IMP-550 from their SlimX line seems to express iRivers' approach nicely: apart from a lovely finish it also sports features more akin to a PC, features I´ve never ever seen on a portable CD player before. You can update its firmware, change scroll speed, alter playback speed, are able to choose between several DSPs, for example a 3D effect or several equalizers. Since it lacks a display iRiver equipped the remote integrated into the headphone cable with a huge display capable of showing ID Tags as well as CD-Text information. I got it for surprisingly little money, especially when I consider the state it was in when it arrived: my unit doesn´t seem to have been used often and if, it apparently has been treated very well. The main reason to own it was the desire to try something else; my motto was "not another Sony." To be perfectly honest, I don´t like the design of the iRiver that much, it tries to look elegant but in my opinion it looks boring and uninspired. But being the owner of a portable player isn´t about design only, isn´t it?

iRiver IMP-550 closeup - Who the hell is "INNO"?

The promise of a well execuited finish certainly is fulfilled: iRiver incorporated several - I assume - quality parts onto its mainboard. The main processor of the IMP-550 is the SAA7750 by Philips (now NXP Semiconductors), it is responsible for decoding lossy audio material, DSP functions - in short all the functions you´d need for a portable multicodec CD player. D/A conversion is achieved by a Sony CXD3023R, regrettably I couldn´t find any information about it. The CD drive itself is manufactured by Samsung and it looks a lot like a drive designed for laptops. While layout and manufacturing of the mainboard certainly look gorgeous this Samsung drive seems to play in another league because it gets very loud when working. But let´s have a look at my measurments now, shall we?

iRiver IMP-550 measurments

iRiver IMP-550 jitter

Wow, I think that these are the best measurments for a portable player I´ve ever seen. No distortions, very little noise, inaudible jitter artifacts - perfect. This should be mirrored by its sound, shouldn´t it? Sadly it doesn´t sound as well as I had hoped after reading all the glowing reviews written by others. It smears details and transients, shows a compressed and not very wide stage while having a preference for very high frequencies. The latter should help definition and resolution but instead it sounds rather opaque. On occasion high frequency details feel as if they´re dissolving into noise, the other end of the spectrum is too thick, obscuring bass punches a bit. The presence range seems diminished which probably is the reason for a sound that never sizzles or seagues into strident territory, its missing attack turns every kind of music into easy listening. The extreme high frequency definition from Episode II soundtrack for example turns into noise, it looses its crispness. The track from "Ray of Light" sounds much too nice and removes the rest of attack this warm and calm sounding album has. I´ve had players like this before; but they at least combined a similar sound with a much better stage impression while also adding a lovely euphonic colour and a certain kind of soothing warmth. Before I measured it I listened to it so I expected it to measure badly, I was surprised when it didn´t. I´m not exactly disappointed by this result because it could be particularly advantageous for albums that have been engineered to sound too aggressive. Yes, it might be a solution for "Loudness War" music - but not for anything else so you, dear reader, decide for yourself.

Sonic Balance:

Dynamics:

Resolution:

Stage / Ambiance:

Character:

iRiver IMP-550 Samsung drive

iRiver IMP-550 line out (with S/PDIF)

Review: Sony MZ-R 55

You´re about to read the second out of nine reviews. You don´t need to read them all, just pick the unit that seems to be the most interesting to you. In the weeks to follow I´ll review the following units: Kenwood DP-5090, Pioneer DV-610, Sony CDP-470, Pioneer BDP-140, iRiver IMP-550, Sony MZ-R 55, Sony MZ-R 37, Sony NW-A 1000 and the Sansa Clip+. Stay tuned and enjoy the second review, the Sony MZ-R 55! I also implore you to read the article describing my rigorous testing methodology before you actually start reading this one.

Sony MZ-R 55

The Sony MZ-R 55 was released to the market in 1998, it was the direct successor to the very famous and reliable Sony MZ-R 50. Both players have many things in common, they each share roughly half of the same parts. Sony reorganized the mainboard design for the MZ-R 55 in order for it to be much smaller, they also altered the power supply so that it would work fine with 3 Volts only. But both players still carry many of the genes from the Sony MZ-R 30. In fact, the MZ-R 50 carried over much of the same parts from the MZ-R 30, only the laser, the drive mechanism (smaller) and the amount of RAM were different. The MZ-R 55 continued that scheme and shrinked the MZ-R 50 drive mechanism further (retaining the high quality laser with its die-cast frame). Sony also changed the headphone amp, the A/D/D/A converter (AK-4517) and drive related ICs. The amount of parts however remained the same with the result that the MZ-R 55 has a tightly packed PCB filled to the brink with parts using all available space inside the small shell. When new it cost around 350,- Euros which is a lot considering it can only record and play MiniDiscs.

Sony MZ-R 55 closeup

While the MZ-R 30 and the MZ-R 50 are famous for their reliability the MZ-R 55 is not 'cause it has a reputation for being extremely vulnerable to anything out of the ordinary. For example David Popovits wrote at Minidisc.org: "A small machine. It looks nice but nothing more. Press stop and in many cases it will start recording. Leave a recorded, unprotected, disc inside the MD during charging and you may find the disc was erased. Drop the machine from a few inches and it will stop recording completely. Use a non-exact power source and it will die partially or completely. Press a bit too hard on the keys and the whole cover will bend. How can we take such a creature seriously?" I don´t want to disagree with David, he seems to be a very experienced fella. Nevertheless I do have a different opinion (until mine will break of course). Its outer metal shell looks exquisite and while it doesn´t seem to be as thick as the one from my MZ-R 30 it nevertheless feels heavy and luxurious. The finish of its entrails looks marvellous too, its drive seems as if built to last forever. The mechanics are also one of the most quiet I´ve heard from an MD recorder... lovely. I would have loved to own the silver/gold version but I´m very happy with its lilac colour scheme too (remember: in Japan this colour is associated with wealth and power; go figure). It looks and feels like a very expensive and heavy cigarette case, albeit one with a conservative purple design. I really enjoy holding it in my hands, to touch it, to press its buttons, to open its lid... ah yes, opening the lid feels great. It doesn´t really pop open with a loud crash like on the MZ-R 30, it just clicks open and you then have to apply slight force so that it finally opens with a soft slide. Boy, I could open and close the lid the whole day!

Sony MZ-R 55 closeup

Running time with the chewing gum battery is ridiculous, it´ll play for two hours before it has to be charged again. Because of that I tend to use it with the attachable battery case (which sadly makes it much bigger) equipped with two batteries. Since I use the wonderful Sanyo Eneloop it can play for hours and hours. BTW, I wonder why Sony supplied a battery case that can hold two batteries - one 1.5 V battery is enough for the MZ-R 55 to function perfectly. Most of the time however the player resides on my Desktop connected to its power supply because I fear that it´ll break in case I use it outside... its bad reputation might be true. But off to measurments:

Sony MZ-R 55 measurments

Sony MZ-R 55 jitter

Apparently it doesn´t have high frequency jitter, only the spread around the base sine indicates some slight low frequency jitter; this might be audible since some peaks are just below -100 dB. The RMAA chart reveals that it is relatively noisy and also has slight problems with distortions (except IMD, those are non-existent). Its sound is... well, very good. The only real problem of the MZ-R 55 is the timidness of the bass, punches at lower frequencies loose their might and impact. Apart from that it´s very balanced, retains much of the character from the reference files and shows a similar level of resolution and definition. Details are never smeared or lost, they show an articulation close to the source. Its dynamic problems do not extend to mids and treble, at these bands it almost sounds like the reference. The stage is way too compact but presents an incredibly holographic depth with lots of focus and an excellent sense of space: far from being a close match but an elegant deviation. Fairly well done, Sony!

Sonic Balance:

Dynamics:

Resolution:

Stage / Ambiance:

Character:

Sony MZ-R 55 in-/outputs

Sony MZ-R 55 closeup

Review: Kenwood DP-5090

This is my first review out of nine. You don´t need to read them all, just pick the unit that seems to be the most interesting to you. In the weeks to follow I´ll review the following units: Kenwood DP-5090, Pioneer DV-610, Sony CDP-470, Pioneer BDP-140, iRiver IMP-550, Sony MZ-R 55, Sony MZ-R 37, Sony NW-A 1000 and the Sansa Clip+. Stay tuned and enjoy the first review, the Kenwood DP-5090! I also implore you to read the article describing my rigorous testing methodology before you actually start reading this one.

Kenwood DP-5090

The Kenwood DP-5090 was released in 1997 and it is one of those players released around that time that managed to reproduce 16 Bit CDs with 24 Bit accuracy... or so. Back then many players claimed to be capable of playing CDs with a resolution exceeding their technical abilities. The proprietary Kenwood D.R.I.V.E (Dynamic Resolution Intensive Vector Enhancement) filter did - according to some reviews - well enough for this player to sound sensational. I´ve read several reviews praising its wonderful sound, many magazines ended up rating it higher than many other units. But we don´t want to concentrate on reviews from the past, we want to rate the real thing.
Build quality is nice as well, the front is manufactured out of thick aluminum, the rest of the case is fairly heavy and equally well built, even the drive mechanism is protected with a thick metal plate. Actually... there seems to be a lot of conflicting information around as to which parts the DP-5090 is actually using. The chaos starts with the service manual: the DP-5090 apparently uses nothing less than three seperate D/A converters. The first is the MN35502 from Panasonic, the second is the CXD2507AQ from Sony and the third is Kenwood's own KAN05. According to the manual only the latter is in use... but the streamlined signal flow depicted in the manuals' diagrams looks so chaotic that I might be wrong. Internally the DP-5090 is pretty similar to the cheaper DP-4090 - the main difference is that the more expensive model uses a combination of several ICs for the DSP stage. I don´t exactly understood if it uses two or three seperate digital filters: the SM5843 from NPC or another filter embedded into the KAN05 itself (or maybe the Sony IC?). In any case, the Service Manual confuses me and the layout seems needlessly complicated. Sure, I´m a layman in that regard... still, todays' much more advanced converters contain all the necessary parts in only one IC. Anyway, the D/A converter (or the whole converting stage) is surrounded by an army of transistors, SMDs, ICs and condensers, the output stage required for amplifying signals once they have been converted to analogue seems equally sophisticated. The player is able to read CD-Text information, it also is equipped with two digital outputs; one can therefore connect it easily to more modern D/A converters. When new it cost 350,- which is not exactly what audiophiles consider High End but it still was one of the more expensive mainstream players. According to my boyfriend (who bought it all those years ago) the DP-5090 never was very reliable, it always had problems reading certain CD-Rs or scratched CDs. That wasn´t an issue for me since the CD-Rs I usually create are of high and flawless quality. On the other hand it is not exactly causing me to invest much trust into it.

Kenwood DP-5090 measurments

Kenwood DP-5090 jitter

As you can see above this player measures exceptionally well, noise and distortions are simply absent. Jitter won´t be audible, it´s extremely low. It´s for sure one of the best devices I´ve ever measured. The sound however wasn´t able to hold up the promise of high quality; the DP-5090 is very far away from being a neutral player. Treble is exaggerated, this creates a lot of air and resolution but it also prompts Madonna to sound hoarse, sibiliant and shrill ("Ray of Light" is actually a warm sounding album). Secondly this player presents a very tight, extremely articulated and dynamic bass response with real punch. This would be wonderful if upper bass wouldn´t be diminished; vocalists lack chest, violins sound thin and brass piercing. True, a signature like this could have its advantages because of extreme levels of dynamics, impact and speed. On the other hand staging is flat and doesn´t show any depth, it´s very audible with organ recordings which crumble apart... well, at least it presents an extremely stable, consistent flat stage. But holographic stage impression? Forget it. This is a very aggressive, dynamic and cool sounding player, it has nothing in common with the sound of the reference files. It will turn music into a fast, coloured and icy warzone, presenting it with much more details and punch than it really has. It will also replace the musics' character with its own, not convincing character. I´m probably kidding myself because I have to assume that many people would actually prefer this sound. Not everyone has perfect neutrality in mind; Pop, Rock or Funk might even sound more appealing with the DP-5090 for some people. Jazz or classical music however sounds just horrible with it so I won´t ever recommend it, except maybe as a transport using its digital outputs. Disappointing.

Sonic Balance:

Dynamics:

Resolution:

Stage / Ambiance:

Character: