Sony MZ-R90 Portable Minidisc Recorder Review

by Marc Wielage
Exclusive for The MiniDisc Community Page
Nov 2, 1999

As the "Size Wars" continue in the battlefield of portable electronics, Sony has picked up the gauntlets flung down by Matsushita with their MR-SJ100 and Sharp with their MT-MD831 MiniDisc recorders. Sony's long-awaited R90 will undoubtedly dazzle MD fans just by its diminutive size, which breaks the record for sheer miniaturization: 3-1/16" W x 2-13/16" L x 11/16" D, without the extra single-AA battery pack. To put this in perspective, this is almost exactly the size of four stacked MiniDiscs without cases. If you clip on the AA battery pack, it adds another inch or so to the length.

The petite R90 makes the earlier R55 look big and clumsy by comparison, weighing about half a pound. Heck, it makes a lot of earlier players look pretty bulky. To my relief, though, the R90 feels very solid and rugged, made mostly of magnesium metal, with only a little plastic on the LCD readout and the Record lever. I could honestly believe that you could drop the thing a fair distance to the floor and have it survive... but for $400+, I'm not gonna be the first to try it.


The top of the R90 has a striking appearance that's evoked a lot of surprising criticism and strong opinions from MD fans. The right half of the top cover has about 30 horizontal ridges cut into the surface, while the left side is smooth. (I halfway suspect the designers took a cue from STAR TREK's "Borg" aliens, some of whom have similar metallic-etched faces.) I personally think the black model is dynamite-looking; for more conventional tastes, the R90 is also available in silver. The almost-identical (and cheaper) R91 is reportedly made of aluminum, but is a few ounces heavier.

The right side has the red Record lever and two Volume buttons (up/down); the left side has six silver buttons for Stop/Charge, Play, Pause, Track-Reverse/Rewind, Track-Forward/FF, and End Search. The middle has a 1" x 5/8" LCD display, with a function lever on the left side. All the buttons are the right size and shape, and have a reasonably-good feel.

The left-most edge of the machine has a 1/8" mini-phone stereo headphone jack and a multipin socket for the remote control. The remote extends the headphone jack, and also uses a conventional 1/8" mini-phone jack. Also provided on the left edge are a stereo 1/8" mini-phone Mike jack (which will power Sony-compatible "plug-n'-power" microphones), and a 1/8" mini-phone Line In jack, used for either analog or digital S/PDIF connections. The right edge has a small sliding cover for the tiny flat NiMH battery pack, along with a small square button near the back for Track Mark. Me personally, I'd rather they had put the Track Mark button on top, but I suspect Sony did this so that there would be less risk of hitting the button accidentally. I think I preferred the placement they had on the R55, which was on the front right edge. The R90's back edge has a unique micro-miniature socket for the 3VDC adapter, along with a screw hole and terminals for the AA battery pack. Unfortunately, you can't attach the AC adapter and the AA battery pack at the same time; I was disappointed that they didn't stick a little DC socket in the AA pack, as they did with the MZ-E55 player.

The front edge of the R90 has the sliding mechanical Eject button. Ejecting is much-improved over all the previous portable MD players and recorders I've used. The Eject lever button pops open at a very light touch, and the disc immediately slides out by about 3/4", making it really easy to get the disc out. I noticed that the disc slot doesn't open quite as wide as the R55, making it more difficult for butterfingered users to try to slip the disc below the slot and jam it. Definitely a wise move on Sony's part, but I have to admit, I'd prefer a "slot-in" design, eliminating the cover hinge completely. I think this would make the unit more "solid" and less likely to break when dropped, though it might also require some kind of internal motor for unloading, which might require a compromise in weight and power consumption.

The bottom side of the R90 has just two small sliding switches: one for "Hold" (defeating all transport controls, so it won't stop recording or playback even if the buttons are pressed), and one for "Synchro Record," which automatically stops when it senses an input signal, typically from a CD player.

The R90 package comes with several supplied accessories, including the AA external battery pack, one NH-14WM NiMH "gumstick" battery (rated at 1400 milliamps), a cloth carrying bag, earbud headphones, remote control, and a 100VAC adapter. The AC adapter is regulated, so it can theoretically be used with standard 120V U.S. AC current, but the adapter will get warm to the touch. I suggest if you plan to power the R90 mostly from AC, get an official 120-volt Sony adapter that puts out 3VDC at 500 milliamps; I've used the R55's adapter with no problem.

Battery Life

To me, the biggest news about the R90 is its battery life, which has been greatly expanded to a whopping 29 hours (!) for playback and 14.5 hours for recording, using both the internal flat NH-14WM NiMH battery and a standard alkaline AA. For anybody who's used these power-hungry monsters for the past few years, this is a monumental achievement. I suspect you could extend this time by 10% if you used one of the very expensive Lithium AA batteries (which go for about $5 each).

This battery life is considerably beyond any comparable unit I'm aware of. I was unable to test the R90 beyond 14 continuous hours of playback, but I can confirm that its battery-life display still showed three "full" cells, telling me it still had plenty of time left. No doubt, the playing time would be lessened if you attempted to drive a larger speaker, or if you repeatedly used the rapid-search or track-marking features. The recharge time for the internal battery is three hours.

With just the internal battery alone, the R90 is limited to about 12 hours of playback and 6.5 hours of recording, which is double the time of the widely-criticized R55. Hats off to the designers who managed the Herculean task of getting the power requirements of the R90 down so low!


Sony has taken the unusual step of removing the previous Mode switches and combined them into a single small lever switch on the left side of the unit. Pressing the button straight in brings up five different modes: Edit (Name, Name Bank, Bank Erase, Move, & Track/Disc Erase); Display (LapTime, RecRemaining, AllRemaining, & Clock); Play Mode (NoRepeat, AllRepeat, 1 Repeat, Shuffle Play); Audio Out (Line Out or Headphone), MegaBass (on/off), AVLS (on/off), and Clock Set (setting both the calendar and time). While in Record, you also get two extra modes -- Rec Volume (Manual or Auto) and Rec Mode (Stereo or Mono). Some functions (like Disc Erase) are only available while the unit is in Stop; others are only available while it's in Play.

To cycle through the sub-menus, you simply rock the lever back and forth. I found this completely intuitive and logical, and never felt a need to consult the instruction manual to go through any of these modes. I did have a little trouble figuring out how to manually set the record level, which is accomplished by using the Track-Forward button to raise the level, and the Track-Reverse button to lower it. Some users may be disappointed that there's no track-by-track programming, but to me, this isn't a significant feature for a portable. A few users have commented that they found the R90's built-in LCD display to be too small, particularly when compared to Sharp's portable MD recorders, but I found it adequate.

Like several previous models, the R90 has enough playback RAM to store 40 seconds of stereo sound (80 seconds of mono), which I think will be enough for most users. I noticed that, in a departure from all previous Sony portables I've used, there's a noticeable delay when you first engage the fast-forward mode. I assume this could be a different philosophy on how they're using the RAM buffer to store pieces of audio. Like all previous recorders, you can shuttle faster through a disc when the machine is in Pause, giving you non-audible cueing.

I liked the new stick-type remote for the R90, which is a little longer and thinner than the one on the R55. The R90's remote, the RM-MZ2S, has a multi-function black button on one end; you push it to stop the player, slide it in one direction to go into Play (or advance to the next track), or slide it in the other direction to reverse to the previous track. If you hold down the buttons, they can be used to fast-forward (or reverse) audibly through the material. The pins on this new remote were compatible with the old one on the R55 and the R50.


Like several previous Sony models, the R90 immediately slams into Record the moment you slide the red plastic lever to the right. This is a major departure from the design philosophy of Sony's table-model MD decks, which automatically check to see if the disc is blank or not. If the disc is already used up, you'll get a "Disc Full" error message on the full-size decks. The R90 will just blissfully start recording and blow away everything on the disc, so beware. If there's already material on the disc, you have to be sure to hit the End Search button first, to avoid erasing the existing tracks.

I was annoyed that the R90 does not automatically go into Record/Pause mode when the Record lever is engaged -- again, a departure from the table-model design. The manual advises the user to hold down the Pause button and simultaneously slide the Record lever, which I found kind of clumsy.

The R90 will not automatically insert Track Marks during analog recording (a feature that is provided on some other portables like the Sharp 831), but will do so when digitally recording from CDs. In a departure from previous models, the Manual Level mode will adjust both analog and digital sources. The level meter shows only one bar-graph, and there's no way to independently adjust left/right record levels -- a common problem of many consumer portable recorders.

Titling is accomplished by cycling through the various characters of the alphabet with the function lever on the left. Both Japanese katakana and upper/lower-case English characters are provided, along with a lot of symbols, including those shown here:

' , / : " # $ % & ( ) * . ; < = > ? @ _ ` + - !

Titling on the R90 is kind of a drag, because of the large amount of characters on the Japanese domestic model. On the plus side, you can title the tracks while playing or recording. If it were possible, I'd almost like to see some kind of infrared port available to allow titling by remote, or maybe even find a way to attach a connector from a PC keyboard. (OK, I'm dreaming on that last one -- given that the keyboard connector is about 1/4 the size of the whole damned machine!)

The R90 is the first portable MD recorder I know of with the "Joint Text" mode, which automatically copies over the CD Text characters from CDs that have this feature. I wasn't able to test this feature, however, since I don't currently own a CD Text-capable player. The Titling also includes a new "Name Bank" mode, which lets you store often-used words or phrases, so you can call them up and quickly use them as part of track or disc names.


The sound quality on the R90 was above reproach, at least as good as the R55 and possibly better. I detected no real difference in terms of tracking or dropouts, but I did notice that the headphone jack is intended only for use with very small, lightweight phones. Don't expect to plug in a 600-ohm pair of Sennheisers and get loud bass from this unit. The supplied "ear bud"-type phones are comfortable to some, but I personally prefer the "sport"-type in-ear phones that use a thin headband that goes over your head. I find those also make your ears sweat a little less, which might be a factor if you use the machine while jogging or exercising.

I don't know the technical specs on the specific A/D's or D/A's used in the R90, but they sounded fairly clean to me, particularly for a portable unit that weighs half a pound. Reportedly, the unit is using ATRAC 4.5 for encoding/decoding, and it had no audible distortion that I could detect, at least on a first-generation recording. I suspect keen listeners could be able to hear subtle flaws with some program material, but for the intended market � serious portable recording fans -- I think the R90 is perfectly fine. Its sound quality is certainly better than any portable cassette deck I've ever owned, and that includes the venerable WM-6C Walkman Pro -- which is the oldest product in Sony's current U.S. consumer electronics line-up.


What would I change with the R90? I've got a few gripes. For one, I can't stand the new location of the track-forward / track-reverse buttons. Inexplicably, Sony placed these two buttons at the very front edge of the machine, flopping them with the normally-found Stop & Play buttons. After a couple of years of using the R35, R50, and the R55, I found it very hard to break the habit of reaching over and hitting the track-forward button by mistake, instead of the Play button.

Once again, Sony has not provided illumination for the LCD display, making it impossible to read it in the dark. The remote wand is illuminated, but lacks some of the displays recordists will want to see, such as record level. I suspect this was omitted simply because of the large drain on battery life and the space (and thickness) needed for a light bulb. Still, I bet all users would really appreciate a backlit LCD readout on the top panel, mirroring the approach by Aiwa.

I missed having a separate Line Out jack as well. Apparently, Sony omitted this in order to save space, since a 1/8" mini-phone jack does take up a lot of space -- comparatively speaking -- on a circuit board. I would also like to see a Digital Out jack, which (to my knowledge) has never been provided on a standalone portable Sony MD recorder. [Sony's first two MD portables, the MZ-1 and MZ-2P, were equipped with digital output jacks. -eaw]

I commented earlier about the lack of Auto-Track Marking, and I'm continually frustrated as to why Sony omits it, given that it's a software feature that would cost them nothing in parts to provide. I personally would like to see auto-track marking at 1 minute, 3-minute, 5-minute, and 10-minute intervals, and make it another Record Mode selection. (A similar mode was provided on one of the ES table models, but no other current U.S. models, to my knowledge.) In my opinion, auto-track marking should be a standard feature on every MiniDisc recorder made, period.

Another minor complaint: the higher-end Sony portable MD players come with the BC-9HU2, which is an AC charger for the little "gumstick" rechargeable NiMH battery packs. I'd like to see this same charger provided free with all of Sony's recorders. In fact, I'd go a step further and ask that the AC adapter have a slot in it so that it could simultaneously charge the machine and a second battery stick inserted in a slot in the adapter itself. And finally, the AC adapter only charges the battery when you push the Stop button; I'd like the adapter to have the ability to simultaneously power the unit and charge the internal battery, if possible.

One last very important comment: Why won't these people provide a carrying case for these delicate, costly portables? It drives me crazy that they often provide a carrying case for a $75 battery-operated CD player, but you get zip with a $400 MiniDisc Recorder. Makes no sense at all. To me, Sony is obligated to provide us a little padded vinyl case to protect the thing and maybe clip it to your belt or something. It'd cost a couple of bucks to manufacture (if that), and to me, it would be greatly appreciated by anybody who intends to use the R90 while jogging, exercising, or just walking. At the very least, they should offer a couple of nicely-styled cases as low-cost options, maybe one heavy-duty one for jogging and a smaller leatherette case for occasional use.

Where To Buy It

Sony's U.S. marketing arm has not yet announced when or whether they'll be importing the MZ-R90 (or the less-expensive R91) to North America. [My guess is that it will be shown in January 2000 at CES in Las Vegas, and will be available in April for about US$400.] The R90 is an expensive machine; it lists for 46,000 Yen, which at current exchange rates works out to about US$350. Reportedly, the demand for it is so high, and the product is so new, few Japanese domestic dealers are discounting it much, if at all.

Most grey-market importers are bringing the R90 in for about US$400 plus shipping and import duty, which adds up to about $450 total. Although the R90 is available from Japan-Direct and several other suppliers, I made the decision to buy it from simply because they were the only ones that could take charge cards. (Reportedly, now also stocks the player, and I've had good luck with them as well, since they take charge cards.)

At this time, my opinion is it's simply too risky for anybody to send cash or checks through the mail to any Internet dealer, because of the lack of protection for the consumer. As with any grey-market import, warranty service on the R90 could be dicey. If you took this into most American Sony service stations, they'd probably look at in bewilderment, as if it came from the year 2525. I suspect with some prodding, local Sony shops could theoretically repair the R90, but would have to charge you the going rate. Caveat emptor!

Despite the nitpicks above, I have to say I'm thoroughly delighted with the R90 in just about every way. Every audiophile I know has been thoroughly impressed with it when I've showed it to them. Now, if Sony could just find a way to cut the machine's retail price by about 25%, and drop blank MD prices to a buck each, I'd say they'd sell half a million R90s in North America alone. :-)

You can find a copy of the English portion of the manual on the Web at as part of the web pages. The manual goes into much more detail on the R90's features and operation. You can find photos of the MZ-R90 and R91 at For different points of view on the R90, you can read Robert Nguyen's review on at In addition, Brian Youn has an excellent, very-detailed comparison of the R90 with the Sharp MD-MT831 at brian_youn/r90831.html. And you can also read users' comments on the Usenet newsgroup
c) 1999 Marc Wielage
All Rights Reserved.

This review may be reprinted without permission so long as it is done in full, without editing, and with the author's copyright notice preserved intact.

Last updated 11/2/1999. [email protected]

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