Thursday, July 18, 2013

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.


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


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:
Stage / Ambiance:


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.



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.


  1. Hello, I enjoyed and appreciated this review of the R50. You write that: " 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" - what does this mean, please. Does this mean the attack of these sound frequencies is more/less faithful to the original source? Thanks.

    1. Thank you for your kind words.

      It means this: the attack/speed of low frequencies (bass) is less faithful to the original while the rest (mids and treble) is almost like the original or equal in quality. Essentially, bass is sluggish.


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