The legendary Sony MZ-R 50 - A review

Willkommen zurück to my blog, dear Constant Reader!

Three months have passed since I last wrote something and while I´ve had several reasons not to write any articles - most of them are explained in the edited blurb now several months old - I still very much desired to return to the one subject that (at the moment) interests me most: MD recorders. As you may remember, I stated in this feature that I won´t tackle MD-related topics anymore for reasons that also were stated in the article mentionend above. Well, this one here bears witness to the fact that I´ve decided to fuck that. I WANT to review MD recorders; they may be obsolete, clunky and not very good yet they ooze charm and force me to concern myself with media I can take into my hand. No one said it better than SileEeles on the MiniDisc Community forum: "I think the main reason I got into MiniDiscs again was because I missed having that physical media. I mean I have CD's boxed up for one reason or another (mostly that they are all on the computer) but I just find that I'm a notourious track skipper on the computer. I don't think I've fully listened to an album for ages, and since I've had my portable player hooked up I've been through quite a lot, and I love it." 

Sony MZ-R 50 from above

I´ll leave it at that. During the last months I´ve also had some ideas how to format my reviews. Articles published before the one you´re reading never felt very organized to me; I´ve therefore decided to equip each paragraph with thematically fitting headlines ('overview', 'sound', 'measurements', etc.). That way it´ll be easier for you to visually skip to the section that interests you the most. I´ve also concluded that it would be prudent to move the section containing measurments to the end of every post; it won´t fit into the middle anymore because I´ve chosen to incorporate more detailed and diverse measurments than ever before. Doing that I hope to gain a new level of transparency for you and myself, dear Reader, so let´s see how it works out. What are you saying, shall we start now? Yes, I think we might.

OVERVIEW

The Sony MZ-R 50 was released in October 1997, a period when MD recorders still had a long way to go entering the conscious mind of the general public (and for some this never happened at all). Judging from the units offered for sale on eBay it sold decently just like its predecessor, the Sony MZ-R 30. When the MZ-R 50 was released to the market it cost a whopping 700,- Deutschmarks (€ 350,-); quite a lot of money for a portable audio player 16 years ago and also more expensive than its predecessor. It seems that the price Sony charged was justified 'cause it soon became apparent that the MZ-R 50 was a very reliable machine hard to destroy. It went on to become something like an insiders' tip for journalists working in the field, emerging as the go-to-recorder for interviews or events when used with an attached microphone. Even after all those years many people remember it fondly and consider it to be the pinnacle of MiniDisc engineering in terms of usability and robustness... though I of course managed to break it the day it arrived.

Sony MZ-R 50: 16 years old and in marvellous condition

I purchased it more than a year ago from an extremely nice lady who sold it through eBay small ads. As you can see on the photographs its condition was close to perfect, she obviously treated this machine with respect, something that never fails to surprise me and always feels delightful. When I receive a used electronic item I usually take it apart to clean it as well as I can in order to restore it to its best working order (I hope). In case of the MZ-R 50 disassembly and cleaning were easy enough, though in hindsight I should have skipped both since it was in lovely condition from the inside anyway. Re-assembling however proved to be my downfall: upon reinserting the mainboard I broke the switch responsible for detecting if the shutter door is closed or open. I was devastated 'cause I had just spent € 40,- for a used recorder I was anxious to listen to, a portable in lovely condition now turned to rubbish by my own hands. I didn´t throw it away though, I kept it as a reminder to treat every future electronical device I might purchase with utmost care. But my bad conscience remained, as a matter of fact it was fueled further by an envelope arriving three weeks later: the nice lady I purchased this unit from had found additional parts when tidying up and sent them to me. You know, some people really do know how to make others happy and all they need to do is carrying something out that isn´t requested of them. Extraordinary. Anyway, among those parts was the fully functional original Li-ion battery!

Sony MZ-R 50 macro picture - beautiful, isn´t it?

Do you know how rare this is? This is the only rechargable battery I´ve encountered still working as advertised. And it wasn´t even part of the original ad, it was sent to me without additional charge (though I insisted on paying the postage for the envelope). If the lady I purchased this from reads this: you´re one of the reasons why I´m hopeful that not all of humanity is a bunch of fucked up idiots. Anyway, I very much desired to repair it - which happened in March 2013 when I acquired a horribly looking and supposedly defective MZ-R 50 on eBay. I didn´t care that it was in such an awful condition, I figured the part most susceptible to wear would be the drive and that the mainboard would be less likely to bust. The battered MZ-R 50 declinated to be salvaged for its mainboard to my amazement still worked perfectly (contrary to what the seller claimed), even though it looked and felt as if a car had run over it. Hmm, the purported indestructibility apparently isn´t a myth at all. So I cannibalized its mainboard and transplanted it into my broken unit. After re-assembling the unit I inserted an MD and... bingo, my MZ-R 50 recognized the closed lid again. Phew, operation successful, patient thriving again. The only thing left to do was calibrating the mainboard to the drive, thanks to Sony's convenient automated calibrating feature this happened swiftly and with perfect results.

Sony MZ-R 50, in- and outputs

After telling you this story let´s return to the features of the MZ-R 50... though I´m afraid there isn´t left much to tell seeing that it´s virtually unchanged from the MZ-R 30. The two major differences are that the more recent recorder is 30 % smaller and that it features a 40-second shock protection buffer instead of a 10-second buffer. Inside, both the MZ-R 50 & MZ-R 30 are almost completely alike. Apart from the optical pick-up and the drive mechanism both feature the same WideBitStream capable ATRAC chip (CXD2652AR), A/D-D/A-converter (AK4515VQ), headphone amplifier (LA4800V, also feeds the line-out), gain control IC for changing the volume on the HP-out (DS1802), system control IC (CXP819P60MR), RF amp (CXA2523R)... yadda, yadda, yadda.

Build quality is marvellous and has been improved over the MZ-R 30; buttons work with tight precision, fit very well without jiggling, the aluminum shell feels superior when touching it. In my opinion the MZ-R 50 also looks better than the MZ-R 30, its casing sports a colour best described as 'silverwhite' that doesn´t look as 'dirty' as the dark silver of the former model. The glossy ornamental belt surrounding the outer edges only adds to its exclusivity and doesn´t look tacky. This unit simply feels and looks superior to the MZ-R 30 in every regard. Battery life is not as good, the smaller Li-ion battery keeps a smaller charge and is drained after roughly six to seven hours (MZ-R 30: eight to nine hours). Skipping from one track to the next is incredibly fast, it takes half a second at max. Almost as fast is writing to the TOC, this takes no more than one and a half second... compare that to recorders that came later (MZ-R 90 for example) which seem to take forever.

Sony MZ-R 50: perfect finish

SOUND

Before you start reading this paragraph I suggest you take a look at the post 'Marlene's testing methodology', otherwise you won´t know how I´m able to judge the sound (I don´t do it like everyone else).

Despite most parts being equal sound quality has been improved considerably. The MZ-R 50 gets rid of the biggest sonic problem of its predecessor: resolution and detail. High frequency intelligibility, definition and differentiation has been enhanced by quite a margin, the MZ-R 50 is able to render it convincingly without turning treble details into noise. 

Dynamics are still too soft, this might have been an intentional decision on Sonys' side (this is at least what the Stereoplay magazine wrote in their review). Bass punches sound too weak, transients in general miss impact and bite. The weak bass however is likely to be responsible for how tight and intelligeble it sounds. Timing is ok but nothing to write home about, it doesn´t reach the speed and snap of the original files I compared it too. Generally speaking, mids and especially treble appear to be faster than low frequencies; combine the friendly handling of transients with this high frequency agility and you´re getting an airy yet pleasant sounding audio player.

Another thing that changed big time - not much for the better - is the staging. The MZ-R 30 sounded confused, you weren´t able to make out size and position of instruments, reverbaration felt chaotic, dimensions of the virtual soundstage were lost. The MZ-R 50 improves on that somewhat by creating three seemingly seperated soundstage 'areas': left, center, right. Instead of presenting the stage as it sounds on the original, (aka one singular virtual stage with perfectly naturally integrated instruments and reverb) it takes it apart into something drier and clustered with players having changed their positions. Width is on par with the reference, depth is not (flatter). On the other hand the virtual soundstage is extremely stable; players might have changed positions but at least they stay there no matter what.

Should you plan on using the headphone output I can safely say that you have to ignore it - it sounds like shit. Employ an additional headphone amp and feed it with the line-out, you´ll be rewarded with a sound featuring less distortions and frequency deviations.

I have listened to this player a lot during the last months and despite its sonic shortcomings I came to admire its sound. It might not present the truth but sometimes an airy and pleasant performance can be very soothing, especially if you use a headphone like the HD-448 which borders on sounding too mellow. The highly detailed, yet unintrusive treble balances out the sound signature of the Sennheiser nicely.

Sonic Balance:

Dynamics:

Resolution:

Stage / Ambiance:

Character:

CONCLUSION

The Sony MZ-R 50 is generally regarded as a classic portable audio player, a reputation that it deserves for several reasons. First, it truly is ridiculously reliable and robust. I managed to destroy it but only because I took it apart. An almost broken unit I purchased on eBay turned out to be fully functional even though it looked like it had been through hell and back. There is a reason that this recorder was used by journalists in the field, it´s small enough to be easily portable, it´s big enough to be handled blindly and it´s sturdy enough to not mind a bump or two. Admittedly, the latter would be a shame 'cause with its perfectly executed finish dents would be a disgrace to its beauty. The sound of the MZ-R 50 is not perfect but it nonetheless shows enough character to be enjoyed by listeners seeking a somewhat pleasant and sparkingly airy sound lacking any ounce of edginess. With audio beauty lies in the eyes of the beholder and in my eyes this little thing is achingly beautiful. In conversations with friends I call my MD recorders my "little precious diamonds", the MZ-R 50 summarizes my feelings splendidly because it surely is an example of a gem almost devoid of impurities. Recommended.

FANCY GRAPHS (MEASUREMENTS)

Line-out

Sony MZ-R 50, line-out, 50 kOhm load (Xonar Essence STX)

Sony MZ-R 50, frequency response, line-out

The chart above doesn´t show anything out of the ordinary, I´d even go ahead and say that it measures well considering it´s a portable device. Distortions are - except for THD + Noise - absent, I was especially surprised how low intermodulation distortions are. This is a first for a portable MD recorder. Not that it makes a difference; the ATRAC codec will add lots of IMD itself. On the graph directly above you can see one possible reason for its slightly bass light sound: deep frequencies decrease for 2 dB at 20 Hz. I don´t know about its audiblity, many skeptics are saying that deviations such as these are not audible. Equally inaudible is the residual high frequency ripple caused by the aliasing filter. Not pictured here is the shaped quantization noise beyond 20 kHz which is so loud that it might pose a problem to susceptible amps and loudspeakers.

Sony MZ-R 50, intermodulation distortion + noise, line-out

Sony MZ-R 50, total harmonic distortions + noise, line-out

The intermodulation distortion graph reveals a very clean sine at 7.000 Hz, whatever you plan on playing back, the MZ-R 50 will only add noise. The same goes for the second graph containing the total harmonic distortions + noise where again it is evident that noise is this units' biggest problem. Even-order harmonic distortion at 2.000 Hz is at -90 dB which is certainly inaudible, odd-order distortion is at an even lower -100 dB. Beyond that: nothing... except noise of course.

Headphone out

Sony MZ-R 50, several loads, headphone out

Sony MZ-R 50, frequency response, several loads, headphone out

Headphone output impedance doesn´t seem to be too high (I cannot measure it yet which means I have to guess; sorry), frequency response is the same for all headphones. The Koss PortaPro doesn´t show its characteristic 100 Hz bass-bump caused by an impedance rising higher around that particular frequency band. The 16-Ohm Sony MDR-W08 also leaves the response unchanged. The high frequency drop-off however could be audible on all headphones. The comparison chart above reveals that low-impedance headphones force the amp of the MZ-R 50 into severe distortions:

Sony MZ-R 50, intermodulation distortions + noise, several loads, headphone out

Sony MZ-R 50, total harmonic distortions + noise, several loads, headphone out

Intermodulation distortions are extremely high with every low-impedance headphone, reaching -45 dB around 120 Hz. Equally bad are total harmonic distortions + noise, especially with the two headphones rated at 16 Ohms (NoName Sony & Sony MDR-W08). Using headphones with 32 Ohms (HD-448) or more (PortaPro, 60 Ohms) distortions are lowered somewhat by roughly 15 dB, but even-order harmonics still show a prominent peak at 2.000 Hz. This headphone output isn´t very good, it seems to be engineered for headphones rated for at least 50 Ohms and it shouldn´t be used as an engineering reference for other portable players if you ask me.

Sony MZ-R 50, jitter, digital input, 16/44.1

From listening to the high frequency detail and agility for several months I fully assumed that the MZ-R 50 would show a lot of high frequency jitter, hence my surprise that it´s completely absent. Well, spotting this hasn´t been in vain because it reminded me again that our ears/brain aren´t the best measurment instruments. Yes, there is some slight amount of low frequency jitter, yet I think it´s safe to say that it doesn´t jitter at all... or it´s at least faint enough to be inaudible.

Review: Pioneer BDP-140

You´re about to read the penultimate 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 new review: the Pioneer BDP-140! I also implore you to read the article describing my rigorous testing methodology before you actually start reading this one.

Pioneer BDP-140 (picture copyright by Pioneer)

The Pioneer BDP-140 is my first BluRay player and the most recent of the bunch. My boyfriend bought it for me last month as a present for my birthday. Until a year ago I didn´t spend one minute on BluRay simply because the picture quality of the DV-610 was so wonderful with upscaled DVDs. At the same time I however noticed that special DVD editions were becoming less common; special or Collector's editions started to be produced for BluRays instead. Point is, I really like to put those nifty looking special editions onto our cupboards (or into drawers, the cellar... where there is available space). I´m a collector and DVD started to become extinct in regard to special editions so I concluded that I would finally need a BluRay player. In September 2012 the BDP-140 was going to be replaced by the BDP-150 (its very similar successor) and as a result it became very cheap: my boyfriend bought it for roughly 100,- Euros (compare that to the 170,- Euros for the DV-610).

Pioneer BDP-140 from inside

Its manufacturing quality is reflected by its price range: compared to the DV-610 it has been reduced somewhat. While the BDP-140 is bigger than the DV-610 it weighs roughly half, probably because everything inside is smaller, less complex with a much higher level of integration. The power supply board for the DV-610 for example is three times bigger, its PCB is twice as big and also contains more parts. When BluRay players first hit the market their cases were filled to the brink with parts, they even needed fans to cool their power hungry hardware. The BDP-140 has only one D/A-converter (a fairly recent Asahi Kasei 4430) which also seems to include the complete output stage... yes, it´s true, I can only see six additional parts for the output in the Service Manual. BUT: I might be talking bullshit here so I´d be thankful if someone could enlighten or correct me. Anyway, the DV-610 was still aimed at analogue playback, it could pass six  analogue channels for Dolby Digital, DTS, SACD and DVD-Audio through its RCA outputs while the HDMI-output felt like a fancy gimmick in comparison. The BDP-140 on the other hand has only digital interconnections in mind, achieved through its modern HDMI 1.4a output. Few people know that it´ll also allow digital output of SACD signals through its optical S/PDIF output with 24/88.2 (2.0). it´s one of only two players on the market able to do that. EDIT: The last two generations of Pioneer BluRay players apparantly have been able to do that, I became aware of it thanks to members from the AVSforum. Since everything can be done digitally the analogue output seems to serve as some kind of spare. Apart from being extremely lightweight it also doesn´t look good from the outside or the inside. The front and the mechanical parts (drive) feel like rather cheap and not well-manufactured plastic and the whole layout appears to lack sophistication and care. The impression I have is that this player is a mass-produced, off-the-shelf creation constructed without love - or so it seems.

Pioneer BDP-140: cheap looking front

BTW, Pioneer didn´t manufacture it, it was built for them by Chinese manufacturer TCL. That might be one of the reasons why several people at for example Amazon.com reported that the drive emits loud noises, that the menu of the player has faults or that the software embedded in the player crashes often - they don´t trust the Chinese even though they have been manufacturing high quality devices for years. I however have not witnessed something like this in the one month I´ve used it: for me it has been working without flaw, played every disc and every file I´ve fed it with so far. The drive is fast and doesn´t emit loud noises, the player also doesn´t get very warm. In short: since I got it it has been working very reliably.

Pioneer BDP-140 CD playback

Pioneer BDP-140 SACD playback

Pioneer BDP-140 jitter CD playback

As you can see on the RMAA charts the BDP-140 measures almost as well as the DV-610; jitter performance has been improved and I´m sure that it´s 100% inaudible. With CDs the sound through its analogue output is equally impressive: as detailed and defined as the reference it only shows a lack of power at the presence range to some extent. I assume that this somewhat laid back sound is also the reason for a recessed stage - but when I say "somewhat" I really mean that it´s hardly noticeable at all. The stage for example is as wide and deep as the reference files yet a tiny bit distant because of aforementioned reasons. The slightly diminished mids are also responsible micro dynamics losing a small part of their appeal. These are the only flaws I could find because it doesn´t have any problems with timing, snap, transients or speed. Resolution and details are top-notch, it also retains the reference files' character. I wish I could tell you that SACD sounds better, I can´t though because it sounds exactly like CD. Just like the DV-610 the BDP-140 resamples DSD to 24/88.2 - but apparently not as well. Taking other reviews I´ve read to their logical conclusion I´d like to point that even the digital output won´t reveal as much of the music as the analogue output of the DV-610. But I´m complaining on a high level... because consider this: the engineering focus wasn´t on analogue output and it still sounds that well? Above I wrote that it seems to be constructed without 'love'... as it turns out you won´t need emotions to create well sounding devices, apparently you´d 'only' need engineering skills! Congratulations, Pioneer:

CD/SACD playback

Sonic Balance:

Dynamics:

Resolution:

Stage / Ambiance:

Character:

Update 17.04.2013: Over half a year has passed since purchasing this BluRay Player. I would love to write that something dramatic has happened (no, I wouldn´t) but this player still performas as expected. Not one Disc it had to play during those seven months has malfunctioned, it didn´t matter if it was a BluRay, DVD, CD or SACD. There has been one complete crash of its system software which was caused by an error I made myself (I was trying out video encoding and created a faulty encoding). Furthermore, during those seven months I´ve come to love its remote. It feels wonderful in my hand (because of mixture of plastic/aluminum), has every button I wish for it to have and seems to have an incredibly powerful infrared light as I can point it anywhere with the player receiving every command. The result is that I can still recommend it, if you should find it anywhere go buy it.

Review: Pioneer DV-610

You´re about to read the seventh 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 new review: the Pioneer DV-610! I also implore you to read the article describing my rigorous testing methodology before you actually start reading this one.

Pioneer DV-610

The Pioneer DV-610 is the first SACD player I bought. I already had collected numerous SACDs beforehand for years without being able to play them back. I knew that I would own a SACD player the moment they became affordable - which finally happened in 2009 when I bought this one for 170,- Euros. But I wanted more and this player appeared to be the device best suited to my needs: I wished to replace my ageing JVC DVD player with a technologically more advanced machine, a player that would read every medium I´d throw at it with ease (including my SACDs). I also wanted to have an HDMI output for possible future use with a modern display. Last year in July we finally bought our first flat screen and for the first time I witnessed a digitally transmitted picture having a quality I didn´t expect coming from DVD. Responsible for upscaling to 1080p is a chip manufactured by Mediatek, this chip (MT1389) also does DSD decoding, mp3 decoding, MPEG 2 / MPEG 4 decoding and whatnot. D/A conversion is achieved by three Burr Brown PCM 1742KE (released in 2005 and still in production), an up-to-date delta-sigma converter incorporating functions into only one IC for which the Kenwood DP-5090 and the Sony CDP-470 needed up to five seperate ICs. It´s also quite expensive when I consider that the Pioneer DV-610 was only a budget model. For SACD its potential is partially unused since the Mediatek chip resamples DSD from 1/2.8224 down to 24/88.2. The huge amount of parts for D/A converter and output stage present in the CDP-470 and the DP-5090 is absent, the Pioneer achieves the goal of converting and amplifying with a much simpler layout.

Responsible for good picture quality at 1080p

Manufacturing quality is ok but nothing to get mad about. The DV-610 is lightweight, its front is made out of plastic and the drive mechanism (by Orion) doesn´t feel too robust (though it still works very well, reliably and fast). It´s certainly not manufactured as well as the Kenwood DP-5090 which probably is the reason that this player and its predecessors didn´t fare too well in reviews when used as a CD/SACD player. Several audio magazines here in Germany compared it against much more expensive players (heavier, more parts, etc.) and - surprise! - they fared much better. As we all know, weight, manufacturing quality and a high price tag are all important for audio, aren´t they? To find out if that´s the truth let´s have a look at my measurments which have been done seperately for CD and SACD:

Pioneer DV-610, CD

Pioneer DV-610, SACD

Pioneer DV-610, jitter, CD

Apart from the amount of jitter the measurments are excellent throughout, noise or distortions are absent. Jitter indicates a mixture of low frequency jitter (the "spread" around the 11.025 Hz sine) and periodic high frequency jitter. However, everything is well below -110 dB so it´s probably inaudible. Measurments are slightly better when the test signal is played back on SACD - this is exactly as it should be since it offers higher resolution. The SNR and Dynamic Range show the skill with which the engineers designed the PCB layout: the DACs are rated at -106 dB, I measured -104 dB which is a fantastic result. Still, I´m slightly disappointed because 20 Bit output quality theoretically allows for a SNR of -121 dB. I know, I know, I´m complaining on an extremely high level, furthermore if someone needs to be blamed it´s Burr Brown for constructing such 'noisy' DACs in the first place.

CD playback

CD material shows dynamic capabilities close to the reference files (transients seem a tad too timid), the stage is well represented albeit a bit too compact and not particularly stable; instruments tend to change their place. Furthermore, the timing is not very good for lower frequencies: bass sounds as if it "follows" the rest of the frequency spectrum where timing and snap are impeccable. Overall EQ displays a little fondness for bloated and too thick bass while treble is diminished a bit which hampers detail and resolution to be reproduced properly. But there are advantages as well: this player won´t ever sound strident, sibilant or shrill, it also won´t sound slow or boring because apart from the bass mids and treble show a lot of speed with a particularly enjoyable amount of snap. Yes, this player really grooves. Sonic colour is the area where the player clearly surpasses the reference; it adds a nice voluptous and engagingly wet yet precise euphonic sheen to the music. This sheen naturally is artificial and not the original but it´s still jolly good fun, therefore:

Sonic Balance:

Dynamics:

Resolution:

Stage / Ambiance:

Character:

SACD playback

When playing back SACDs the Pioneer DV-610 sounds... well, it doesn´t really sound. It was extremely difficult for me to hear any difference to my reference files at all. Dynamics are almost perfect, the timing problem audible with CD material vanished upon playing SACD. Staging sounded like a carbon copy of the reference, just like resolution, level of detail and colour. Still, stage and imaging on occasion show some tiny difference, sometimes instruments seem to be placed rather strange with the left channel sounding as if coming from behind (don´t know how else to describe it). But instead of creating a euphonic colour the player now sounds perfectly neutral and completely retains the character of the recording. Any deviation I´ve just described is tiny, but I have to mention it and I will therefore substract one point for dynamics & stage. The pristine sound with SACDs leaves me with only one possible rating, the highest I´ve ever given to a player:

Sonic Balance:

Dynamics:

Resolution:

Stage / Ambiance:

Character:

Pioneer DV-610 close-up

Sound quality differences with optical outputs - why?

For years I haven´t been bothered with digital S/PDIF connections. I basically stopped using them in 2001 when I got rid of my MD deck. This deck had been connected using its RCA digital input, only because everyone was saying that these gave superior sounding results. I never actually checked out if this was true with the result that I ignored optical Toslink in-/outputs back then. But my recent encounters with the Sony MZ-R 30 and the Sony MZ-R 900 forced me to use them again - they are the only way with which I can achieve digital copies with these MD recorders. Thankfully many of my vintage portable CD players are equipped with an optical TOSLINK interface, sometimes I also bought them for this reason. With an optical cable I can connect my PCDPs to an MD recorder to create a digital copy even including trackmarks automatically set by the MiniDisc recorder.

Optical mini-Toslink on the Sony D-335

During the last few weeks I recorded roughly twelve MiniDiscs. Some were recorded with the respective CDs played back by my Sony D-465 or the Sony D-335, some were recorded with the Creative Soundblaster X-Fi HD USB as their the digital source. To my surprise the CDs copied with those two CD players sounded different to what I´m used to, it was apparent that the sound signature had been changed somehow. The ones made with my Creative sounded pristine instead. To use an analogy: recordings from my CD players sounded like a decent analogue copy while the ones from the Creative sounded like the originals. But how can this be true? In both cases I used an optical cable that transferred its data digitally, effectively creating a second original (ignoring the lossy ATRAC compression). All the digital outputs I´ve used so far are bit-perfect meaning they won´t change the digital signal in any way. I´ve confirmed this with one of my CDs from TELARC, a rare example of a DTS-recording they released some 15 years ago. Our Sony STR-DB 830 QS is able to recognize the digital signal as DTS-encoded, it doesn´t matter which device is doing the playback. So why do I hear differences between digital signals? It just doesn´t make sense.

My optical fiber cable (copyright: Philips)

The cable you can see above is the one I´ve used for all my tests involving MD recorders and my Creative. Build quality is good... the gold plated "connectors" don´t make sense of course; the signal is pure light and cannot be influenced by the conductivity of certain metals. People seem to expect it though... what the heck, it looks nice doesn´t it? Back to the question of why I´m hearing differences. The S/PDIF protocol necessary for digital Toslink transfer has several disadvantages. The most significant is that the receiver of the signal doesn´t control it, the sender does. Because of that it must synchronize its internal clock (necessary for D/A converting) to the one contained inside the signal itself which is generated by the device transmitting it. Now in case of jitter (you knew that I would mention this, didn´t you?) introduced by an unstable or polluted clock the receiver (D/A converter or MiniDisc) won´t have a stable clock reference, in effect making jitter audible upon conversion to analogue signals. Research into this subject has been going on for years, for example from members of the AES. This influence can be reduced of course by reclocking the incoming signal. Both my MiniDisc recorders do exactly that: they reclock the signal with their built-in samplerate converter, effectively creating their own clock reference. Another impermeable wall for jitter is the MiniDisc writing process itself because it is another reclocking step. All of this should in theory eliminate jitter completely. Would it be able to survive it would result in distortions not unlike those found in intermodulation distortion and in a compromised stability and clarity of the stereo image. How are my MD recorders doing this reclocking? They probably use a phase-locked loop circuit (PLL) which you can imagine as a huge flywheel averaging out speed variations. Depending on the quality and implementation of the PLL jitter reduction is more or less successful, according to an article from Soundonsound it cannot ever be eliminated completely though. Attention: even with jitter the transferred signal will always be the same, it still contains the same 0 and 1, albeit at different places (sort of).

Jitter test signal on MZ-R 900, played back by Creative Soundblaster X-Fi HD USB

Jitter test signal on MZ-R 900, played back by Sony D-465

Look at the two pictures above by clicking on one of them, then scroll through them with your mousewheel. They were created employing the Sony MZ-R 900, its analogue output recorded with my E-MU 0202 USB. I set the MD recorder into record-pause mode in order for it to serve as a D/A converter only without the result being distorted by the ATRAC encoding. In both cases I used exactly the same signal, it´s the jitter test I usually use for my vintage portable CD players. In case of the Creative it was played back by foobar2000, utilizing the WASAPI interface of the soundcard - without resampling of course. Exactly the same file (this time burned on a CD-R) was then played back by the D-465. Level matching was unnecessary since both results have the same gain. On the pictures you can see that the spread of the signal is wider with the Creative. With the signal played back by the D-465 however there are additional sidebands absent with the Creative. The example below also exhibits a noisefloor higher for roughly 1-2 dB. While I assume these tiny differences to be insignificant, they (or something else) do have an audible effect on music. Recorded from the D-465 music has an unsharp and compact image, sounding a bit bloated and less crisp. Piano for instance sounds a bit distorted while strings loose their gloss. All of this was restored to normal when the Creative was used as a digital source for recording. I even did a DBT, not only for you but also for myself to make perfectly sure that I wasn´t hallucinating these differences:

foo_abx 1.3.4 report
foobar2000 v1.1.13
2012/06/25 20:54:42
File A: D:\Coast Guard Rescue Creative.wav
File B: D:\Coast Guard Rescue D-465.wav
20:54:42 : Test started.
20:56:15 : 01/01 50.0%
20:57:00 : 02/02 25.0%
20:57:29 : 03/03 12.5%
20:57:48 : 04/04 6.3%
20:58:08 : 05/05 3.1%
20:58:26 : 06/06 1.6%
20:59:45 : 06/07 6.3%
21:00:00 : 07/08 3.5%
21:00:06 : 08/09 2.0%
21:00:41 : 09/10 1.1%
21:01:01 : 10/11 0.6%
21:01:08 : Test finished.
----------
Total: 10/11 (0.6%)

For this DBT I recorded the same track ("Coast Guard Rescue", The Perfect Storm) twice, again with the D-465 and the Creative. Level matching was unnecessary as both had the same level, they needed precise alignment of course in order for the DBT to be successful. By this example you can see that different digital sources might have an impact on sound, even when they are bit-perfect. I´ve subsequently tested several other players and their digital outputs: all my portables appear to be susceptibe to something that distorts the digital sound while still being able to transfer a bit-perfect digital signal. There was only one portable player coming closer to the clarity of the Creative transferred signal, the DE-J 725. It didn´t sound bloated but flat and uninvolving (strangeley mirroring its analogue signature). The player almost sounding like an exact clone of the Creative was my Pioneer DV-610 AV which is nothing more than a simple DVD player. Are the reasons for this jitter? Or is it something else? I´d like to know if you, dear reader, have made similar experiences. Maybe my portables do have an unstable clock source or their signal gets distorted by other factors unknown to me yet. In either case the Creative once again proves itself to be a very reliable device of high quality. Additionally a clean digital signal from the source seems to be vital for perfect sound. To all the doubters out there: a bit-perfect realtime signal doesn´t mean that it´s free from some kind of distortion! You might now think that everything is a bliss - you are mistaken there. Recording to MD with the Creative is quite tiresome, trackmarks are not transmitted and therefore I have to set them myself after recording which essentially means that I have to divide a single, 60-minutes track into several pieces. But I´m obviously not a person that loves convenience that much (Exhibit: using MD recorders) so my desire for quality usually gets the upper hand and in the end I´m rewarded with perfect sound quality from MiniDisc. Before I forget: my reviews for the MZ-R 30 and the MZ-R 900 have been done with recordings from the Creative.

Last update: 10.01.2013