A lot has been written online about how much better batteries are for our walkmans, and I'm assuming this means other brands besides Sony. I want to share my solution because I use my WM-D6C in my two channel home stereo setup quite often. I thought it would be easy to find a decent power supply, but I was wrong and I could not see putting a seven dollar switching power supply into my almost irreplaceable walkmans. So I re-searched, and I am assuming that this Casio is a linear power supply, but of course the plug did not match my Walkman. So I bought the cheap seven dollar power supply just so I could get the end off of it, and then I just cut the cables on both and spliced the correct and into the Casio power supply. In a perfect world I would have used a good crimp connector, but the wire is pretty delicate and I just decided to splice them together and electrical tape them very well. I tested both of them for output voltage, and surprisingly the cheap switching power supply was almost dead on at around 6.10 V, but the Casio was even closer and right at 6.0 V output. Since this was my first time messing around with an external power supply for my walkmans I'm glad I researched it because as all of you know most/all of the new power supplies that are sold today have the polarity reversed, and it's the inside pin that's the positive, unlike ours that need the outside to be positive. One little mistake and our delicate electronic parts would be fried. Here is the model number to the Casio supply that I used, and it works so well that I bought a second one, because that's how we roll, and what sane portable stereo person would buy only one lol. As a sidenote, even a typical AA battery doesn't put out exactly 1.5 V who knew? These are available on eBay, and just a great linear power supply from back in the day and is pretty hefty; Casio AD-K64 AC Adaptor Power Supply Output 6VDC 800mA This is a typical switching power supply sold by a half dozen sellers on ePay, and this one had to correct polarity. AC Adapter For Sony WM-D6 WM-D6C Professional Walkman Recorder Power Supply Cord
Three comments Casio are also (in)famous for using centre negative power supplies on their keyboards Like many PSUs from the 1980s/90s Casio supplies were unregulated so could go up by about 30% when not loaded. While switch mode supplies are far more accurate they always have the potential to add noise to sensitive analogue circuitry. I would think the best PSU would be a regulated linear one. You used to be able to get those from the likes of Radio Shack / Tandy. This sort of thing. They do tend to be quite large and heavy. https://www.ebay.co.uk/itm/304550936328
Hi, It's not going to matter because the power plug doesn't fit any walkman anyway and has to be changed. What I did was get the correct plug where the outer part is the positive and the center negative, and just hook up the positive and negative wires from the Casio into it. Perfect 6.0 V. It's obviously regulated, because I tested it and it's never strayed away from 6.0 V while not under load. The Casio brick that I got was from the 1980s or 1990s, and it's also large which means it's a linear and not switching. By definition of linear power supply is regulated; Linear regulated power supplies gain their name from the fact that they use linear, i.e. non-switching techniques to regulate the voltage output from the power supply. The term linear power supply implies that the power supply is regulated to provide the correct voltage at the output.
Yes you can tell that is linear from the size of it, and old from the fact that it was "Made in Japan". I can't fault your choice there although it could be difficult finding another. p.s. the silly thing is that the components needed to add regulation to a linear supply only cost a couple of dollars. However, in items like the keyboards it was probably only necessary to regulate the digital supplies while the power hungry audio amplifier could cope with a wide range of supply voltages.
I almost always use NiMH rechargable batteries in walkmans because of 3 aspects: - convenience (with a supply they're not so portable anymore); - new type NiMH batteries last more than long enough for normal use, so I rarely feel the need for an external supply; - the fact many linear power supplies (especially the unregulated ones, but even some regulated ones) will introduce audible hum in the audio; The center negative thing, I incline to believe it may be more of a Japanese thing than an 80s thing: I have a Brother label printer (Made in Japan) which has a center negative barrel plug despite it's a recent model. Then as far as power supplies goes, regulated ones are ok to be used, but I must point out people should test for that before assuming that a linear supply is regulated because most are NOT. For the WM-D6C, adding a 5V low-dropout regulator is the best choice, as 6V might be too much for it (has been explained already in a dedicated thread). A mod similar to this (but with 5V output) is what I recommend if one really wants to use the D6C with a power supply: https://stereo2go.com/forums/thread...y-mod-also-applies-to-ac930a.8429/#post-65051 If I had that Casio and wanted to use it for the D6C, I would simply replace its internal regulator with a 5V one instead of the 6V. The term "linear" does not imply that a supply is regulated. The 2 are completely separate. Linear means the active devices (diodes, transistors) are operated in their linear region, not fully on/fully off (which is done in switching supplies). The simplest form of linear supply (which is also the most common) consists of a transformer, a bridge rectifier and a filter capacitor. This type of supply is not regulated, so will have a higher voltage when in no load condition and will also have quite significant variation with mains voltage. The regulated form of this supply also has a series pass element (being it a bipolar or MOSFET transistor) that controls the output voltage. The disadvantage of such a regulator is that most generic ones will require quite a high voltage drop to regulate properly, hence they will dissipate quite a lot of heat under high load conditions. For example, a LM7805 requires a minimum voltage drop of 2V at the rated 1A current. So one will need at least 7V at its input, in practice it will be more since you need some headroom to account for variations with mains voltage. So, with a 7.5V input, you will have a 2.5V drop across the regulator. Multiply that by 1A and that gives you 2.5W of power dissipated. You will need a big heatsink for that ! Hence the reason why such regulators weren't used as much (apart from the added cost). But nowadays low dropout ones are much more common and one can easily find a regulator with dropouts as low as 200-500mV at full load. The WM-D6C has a rated maximum current consumption of 150mA when recording on TYPE IV tape (so highest bias voltage). In this case, adding a regulator is not that hard at all. On the other hand, switching supplies are almost always regulated unless the load is constant (which is rarely the case).
overmodulated: "It's obviously regulated, because I tested it and it's never strayed away from 6.0 V while not under load. The Casio brick that I got was from the 1980s or 1990s, and it's also large which means it's a linear and not switching. By definition of linear power supply is regulated." These are incorrect statements. Regulation should be determined as no voltage change between NO load and full load. All linear power supplies are NOT "by definition" regulated. Linear and regulated are two different things.
"If I had that Casio and wanted to use it for the D6C, I would simply replace its internal regulator with a 5V one instead of the 6V." Not a bad idea. I wonder how hard it is to get inside the Casio supply.
The barrel measures 3 mm inside diameter, and 5 mm outside diameter. I have not used the Casio power supply very much on mine because of the answers in this thread. Obviously I was wrong about this power supply, and as much as I wanted it to work it’s obviously not optimal. Makes a great paperweight lolol.
I don't see why the Casio AD-K64 won't work just fine if you heed the precautions mentioned by Deb64, Valentin, and others. You need to put in a 1N5818 diode in series with the WM-D6C power feed to prevent damage from reverse-voltage, and an MCP1702-4002E regulator in series with the DC feed to the fragile CX20084 motor IC to prevent overvoltage destroying the chip. Once that is done the Casio should be fine, though I agree with Valentin that it would be safer with a 5 volt regulator. "The barrel measures 3 mm inside diameter, and 5 mm outside diameter." That's ONE measurement; another: "5.55mm outer diameter, 1.9-2mm inner diameter, measured on the original plug from a compatible Sony AC adapter." Hmmmm.......?????? Anybody got a part # of a connector that will fit?
I also always use my D6C with eneloop rechargeable batteries. But considering the claims that they would work well with a 5v source, wouldn't it be possible to use a cell phone charger with a USB cable adapted to the center negative output compatible with the D6C? As far as I know, current original cell phone chargers have good stability, are compact and easy to find.
As far as I am aware, cell phone chargers are switch mode type. I would not use one on a D6C or any other walkman with a CX20084 chip.
@Deb64 Hi, I’m not versed in this at all, is there a way to tell if I opened up this Casio power supply if it’s regulated or not? If I took it apart and took a picture would you be able to tell?
Cell phone chargers are indeed switchmode, have been like that for a very long time. @overmodulated Yes an unregulated power supply will have just a bridge rectifier (can be integrated or 4 diodes) + filter capacitor. A regulated supply will have a regulator (IC or discrete) apart from the rectifier and filter. However it is to be kept in mind just because there is additional circuitry it doesn't necessarily mean supply is regulated. Some supplies can have overload and short circuit protection, but no regulation. Upload a picture here and we'll judge based on that.
Great I’ll see if I can figure out how to get it apart, but I think it snaps together, unless there’s a screw under the label.
I’m going to mess the case all up if I try anymore. Plus the plastic is 40 years old and I’m afraid I’m going to break it. Tight as a drum.
This power supply was made for a Casio LCD pocket TV, and made in the mid 80s sometime. I would think when they first came out, or the first five or six years of those types of TVs they were pretty delicate. Let’s say this is an unregulated linear power supply, and I did test it, and it output exactly 6 V. It’s also rated at 800 mA, but we know that a device is only going to draw whatever mA it needs. I’m not an expert, but I can’t imagine that Sony of all companies would rate something at 6 V if it couldn’t handle it. They recommend alkaline batteries, and I know 4 of them are 6-6.3 V. Is it possible that the voltage in the Casio is going to vary much at all due to the WM-D6C’s approx 200-300 mA draw? This is speculation only, but I think many of the units that were damaged, was human error. I think many of them did not know about the correct polarity with these, and blew the chip out themselves. I mean some uninformed people think you can plug anything into anything as long as the plug fits it’s good to go. Just my thoughts, and I’m not trying to justify the use of my power supply, I want to get to the bottom of it if it’s safe to use or not. I have not used it because I’m scared too now because of everything posted.
I put this question to the gentleman that fixed my Walkman, and he advised against any external power supply also. Rechargeable batteries it is!
Casio AD-K64 Well, I found one on eBay for $10 shipped so I bought it. It measures 6.03 volts unloaded and 5.76 volts under a full 750mA load, so it is regulated...sort of. 4.5% regulation is anything but stellar: a run-of-the mill 7805 will do much better than that. It does not appear to accommodate servicing of any kind---the case is not easily removed, so me and my dremel tool will have a look inside to see what can be improved. Unless someone out there has a better idea....
