USB Powered MD

[xispe]

hi people!

I've got tired of recharging my battery of my MZ-R70 every day that i went to work! So i've decided to build my own USB powered interface for my md! allright! :grin:

The MD should receive 3 Volt DC, but after measuring the output of the original sony adapter, it was around 5 Volt DC. The USB delivers exactly 5 volts, so there shouldn't be any problem!

So here it is, i've only bought the input jack. The USB cable (white) i had at home... it was a USB to PS/2 converter from my keyboard that i wasn't using... I've connected the red USB wire (+5V) to the middle of the connector, and the black USB wire (GND) to the border of the connector. And i've only spent 0,45 € bahahhah. :laugh: :laugh:

And it works! :happy:

funky! :rasp:

[Christopher]

Wow, this is definitely a sticky! You're quite the risk-taker, I'd be afraid that my unit would blow up if I tried anything like this. If you post a full guide it might be able to make front page news on minidisc.org, ya know. I can think of alot of people that would find this handy..

[skyther]

The output from the Sony adaptor isn't regulated. Under load, it'll drop to around 3V.

Could be potentially dangerous.

[xispe]

The output from the Sony adaptor isn't regulated. Under load, it'll drop to around 3V.

Could be potentially dangerous.

opps... ok thanks for warning me.

I'm going to apply a voltage drop of 0.6 * 3 ~= 2 volts before the main plug using 3 diodes. Like this i'll send around 3 volts to the unit.

i'll post more pictures later, and if i have time a full guide

BTW: i took this risk because i've seen in the service manual that the unit has a 2.5 volt regulator inside :smile:

[xispe]

ok, with 4 diodes in series i was able to get 3.2 volts in the output :smile:

here's the picture of my outstanding soldering skills (not) :wink: :happy:

now i'm going to try put this inside the connector :laugh: (lets hope it fits...)

[xispe]

ok! it's done!

I've tried to put all the 4 diodes inside the connector, but it was wayyy too tight!

So i decided to put the 4 diodes in a straight line...

I had to cut a bit of the usb cable... put everything inside, close bla bla bla and insulate the best i could with the black tape.

And the result is:

It looks worst than the first one, because i had to cut the cable, but now its just outputing 3.2 volts to the MD (not so dangerous!). :rasp:

[The_Stamp]

wow, you should go make one for the hi-md! (the 600)

[mAjEsTiC]

heyyy nice job... :happy:

[xispe]

yep, it works

[liljoeyjordison]

wow, im guessin you work with electronics or something? i take the route with you can mess with anything as long as you cant get fried, burnt, or lose however much money on a md.... so yeah good work *thumbs up*

[Daijoubu]

Looking at his soldering skill, no?

Keep in mind that the USB port can deliver a limited amount of current and try to not overload it

[Daijoubu]

I tried for myseld, using a diode zener of 3.9V (output is around ~2.9 when meseared)

Guess what happened? My mobo cut the power of those ports

So there's a difference between low-powered USB device (100mA max) and high-power (500mA)

Now how can I tell the computer I need 500 and not 100...hmm

What diodes did you use?

[xispe]

i used the standard ones, i don't know the reference right now, but they are the most common ones. Non zener.

[xeroxide]

standard in4004 diods take .7v so i think thats the type to go with.

[xispe]

yep, that's the type of diodes to go with.

[MDX-400]

I know this is an old thread but since it is stickied...

Why was everyone so concerned about the 5V that the original cable was outputting? Because newer MD units, including pretty much all the NetMD models have a degree of protection on their DC inputs. Since the original cable worked I would say that there wouldn't really be any problems with using it that way. At your own risk of course... But the truth is if you apply about 6 or 7V to the DC in on a newer unit, it won't fry it. Instead you'll get a message on the MD unit saying "Hi DC In" and the unit activates its protection circuitry. Certainly, given enough voltage you will likely fry the unit but 5V DC, even constant, isn't going to harm anything.

Unless you have some sort of power surge through your PCs power supply you'll be okay, plus motherboards usually have some kind of regulation for the USB ports too--if you did get enough voltage through the USB to fry an MD unit your motherboard would probably be fried as well.

[Loonie]

Allow me to tag a "little bit" on to this thread.

Bear in mind that to charge a 3 volt battery, you would need to put more that 3 volts across it. Basically, best way to remove doubt is to measure what the official Sony PSU is putting into the player when under the load of charging. Yes, reasonably new units should be pretty well protected, though I can understand a reluctance to shove unknown quantities into expensive gear.

The newer Sony PSUs, as with most around now, appear to be switch-mode. That makes 'em smaller and cheaper than their transformer-based counterparts. Another advantage of that is that they are multi-region (I bought my NW-HD3 in the UK, and can use the same charger here in Canada. Provided I use an adapter to allow the UK plug to fit in the Canadian socket, of course). If you look on one of these PSUs, it even states "input: AC 100-240V~". Switch-mode has certain other implications to take into account.

Transformer-based PSUs rely on stepping down voltage according to a ratio of independent primary and secondary windings on an iron or ferrite core. For example, a transformer with 1000 primary turns and 200 secondary turns will produce an output at 200 divided by 1000, 20%. 100 volts in yields 20 volts out. Transformers drop power as the load increases because the windings themselves are not perfect conductors, and will be subject to Ohm's law, V=I*R. The current being pulled through the transformer, multiplied by the resistance of the windings, equals the voltage that will lost to that effect, which will be dissipated as heat. Okay, so it's a little more complicated than that, inductive loads, AC and so forth, but that's the jist of it. I shall ignore the bit of electronics responsible for AC-DC conversion for now, though it of course has an effect too (as someone here previously pointed out, a silicon diode, as used in rectification, has a 0.6V difference between anode and cathode).

The idea behind switch mode supplies is that the desired output is created electronically by taking the input voltage and switching it on and off really quickly through a whole bunch of coils, capacitors and other assorted crap. The controlling electronics monitor the output and vary the switching rate when required. If the load increases and the output voltage starts to dip, the 'tronics will pump more juice in, until the required voltage is once again restored. This is why they can generally handle multi region. They just switch the input at a different rate. The switching happens very quickly, which is why switch-mode supplies, like laptop charges, make a kinda squeaky, squealy noise, whereas transformers make that 50-60Hz buzzing sound.

So, where am I going with all this switch-mode talk, and how is it relevant to this, and what the hell am I talking about? Well essentially, switch-mode power supplies, by nature of how they work, are regulated. Not necessarily super-clean, but reasonably consistent under load (at least until the switching process is pushed to the point where it breaks down, or where the current limiter kicks in). The output voltage is rated at 6V on my NW-HD3 charger, and 6V is what ya get, whatever the load.

As for transformers, when they are rated at for example 12V @ 500mA, that means the voltage out of it is around 12V when under load, ie when you are drawing half an amp from it. When not under load at all, the output is more likely to be around 14-15V. If a transformer-based Sony charger is rated at 5V @ 300mA, that means when under a 300mA load (ie charging the battery), the voltage from the supply should be at 5V (...not that Sony would ever deviate from an established rating convention like that, no sireee...).

As far as this case is concerned, PCs use switch-mode supplies, and the motherboard voltage regulators are also switch-mode, on account of better efficiency and lower heat when compared to linear regulators. If the minidisc is rated at 5 volts, in theory it should be absolutely fine to feed it 5 volts from the USB, provided the USB can supply the required current.

This is a somewhat crude breakdown of the theory, but hopefully may prove of some use to those exploring this avenue of alternative charging methods.

Edited August 25, 2005 by Loonie

[MDX-400]

If the minidisc is rated at 5 volts, in theory it should be absolutely fine to feed it 5 volts from the USB, provided the USB can supply the required current.

Actually the MD units are usually rated at 3V which is what the concern was about. I don't know about the new Hi-MD units but the older non-Hi-MD units mainly came pacakaged with transformer-type AC adapters. The float output from a 3V AC adapter is therefore above 5V and as you explained (very well I might add ) which is why the original person thought that 5V from the USB was okay. There was a concern that since the transformer adapter would go to closer to 3V under load that 5V constant (from the USB) is too much. However that just isn't true because of the fact that I described above--the newer MD units have a degree of protection--if they are overvoltaged they display a warning on the display and lock out the power to the unit.

This is a somewhat crude breakdown of the theory, but hopefully may prove of some use to those exploring this avenue of alternative charging methods.

Actually I'd say it was a pretty darn good breakdown!

[KrazyIvan]

provided the USB can supply the required current

That is the problem, it can't. Best case scenario you will cause an instability and your system will reboot itself. Worst case scenario you will phisically damage the motherboard or yourself.

Now if you tried this with a powered hub it may be a different story.

I highly recommend not trying this from the motherboard USB header or any USB header directly on the computer itself. I am speaking from first hand knowledge.

[Sparky191]

That is the problem, it can't.  Best case scenario you will cause an instability and your system will reboot itself.  Worst case scenario you will phisically damage the motherboard or yourself.  ...

How can it do that?

[KrazyIvan]

Due to the nature of my work I cannot go into details.

What I can say is when you overdraw the USB bus strange things can happen like uninitiated reboots or lockups. In extreme cases I have seen motherboard USB headers burned, motherboard traces burned. Small fires started by overdrawing current from the USB bus.

Think about it. Most every item that has some sort of USB cradle has a seperate AC charger that plugs into the base of the charger. Why? Because in most cases the USB bus is not capable of providing the current necessary to charge modern day devices. There are items that can charge via USB like cell phones but the current draw is minimal.

To be compliant with USB specifications a high-power function must not draw more than 500 mA from the bus during normal operation.

Most devices that don't have an AC charger connected to the base do not charge the device. Some devices that come immediately to mind are PDA's. The USB dock always has a seperate AC charger. There are MD units that cannot be charged via USB even though they have a USB dock.

I have to take back my comment that it "can't" be done. Maybe I should reword it to say "Be very very careful!" As long as you fall within the USB specs for current draw you should be okay.

National Semiconductor has an interesting article that is relevant to this discussion. It pertains to Li-Ion charging but maybe some knowledge can be gained from looking at the schematic they have for the charger they propose:

http://www.national.com/appbriefs/files/AppBrief101.pdf

[Sparky191]

Any device I've seen that can't draw enough current from one USB port, uses a Y cable to draw power from two ports. Like the faster and larger capacity 2.5" Hard disks.

[tuemura]

If de desire is to charge using the USB port without burning your PC USB ports out, you should take a look at this:

http://www.ladyada.net/make/mintyboost/process.html

You can create a circuit to charge your device using a USB cable and two AA batteries, i think that is much more safe, effective and portable.

[Sparky191]

....Think about it. Most every item that has some sort of USB cradle has a seperate AC charger that plugs into the base of the charger. Why? Because in most cases the USB bus is not capable of providing the current necessary to charge modern day devices. There are items that can charge via USB like cell phones but the current draw is minimal.

Most devices that don't have an AC charger connected to the base do not charge the device. Some devices that come immediately to mind are PDA's. The USB dock always has a seperate AC charger. There are MD units that cannot be charged via USB even though they have a USB dock.....

I don't agree with you on this. I've had PDA's which have cradles and AC ports which also charge from USB. Same with Mp3 players, mobile phones etc. The AC and cradle is for convenience not because it can't pull power from the USB port. Main devices that need more power, come with USB Y cables so you can pull power from more than one USB port.

http://www.bixnet.com/5vps2powercord.html

http://www.pexagontech.com/products/cables...it-drive-61.php

I've use these with USB 2.5" Hard Drives for many years with no problems. Even with up to four drives connected to a machine. I usually have 2 connected up to my laptop for example. The only propblem, I've ever experienced where theres not enough power on a single cable is that the device wouldn't charge or power up. Its not unsual in my experience for USB ports to be below the USB spec for power. Even in a machine with 5 or 6 USB ports you might find only two of them meet the spec.

Edited June 1, 2007 by Sparky191

[ronny69]

I tried for myseld, using a diode zener of 3.9V (output is around ~2.9 when meseared)

Guess what happened? My mobo cut the power of those ports

So there's a difference between low-powered USB device (100mA max) and high-power (500mA)

Now how can I tell the computer I need 500 and not 100...hmm

What diodes did you use?

Hi!

I think you should use 1N4148 or 1N4004 or equivalents for the diodes.

But why just not put in a +5V regulator? That would be more relaxing,maybe?

-Chiron

Norway

[Strungup]

I have a Lith Ion batt pack , from Filco /Diatec 4.4 amp hours 3.7 volts , with a USB out , it charges from 5 Volts DC , I just tried to charge it from my Macbook Pro, right USB and Left did the same thing , a Pop Up warning window comes up , and says " The device connected is drawing too much power and the USB port will be deactivated"

That should answer everyone here , Ivan is giving fair warning and is obviously correct , I just wanted to test it out . Certain devices can indeed charge from USB as long as the power requirement is within base values , but on a computer with an OS that doesnt give a warning like OSX will , you stand to do damage if you arent completely sure of the needs of what you have connected.

[Sparky191]

Nice thread revival.

I take the point if you have a faulty or out of spec device or faulty or out of spec USB port/motherboard, it could damage the USB port and the motherboard its on. This would be especially a concern from a home made device. However I've never had a problem with USB charging in many years of doing it with my laptop. One of my current laptops which a couple of years old regularly has up to 4 USB drives 180~320GB running from USB power plus a MP3 player, and a phone charging from it all at the same time. I've not had any problems. I've worked in IT for years and never seen a problem either with boards being damaged from it either.

Maybe theres a problem with the device you are using, and/or maybe theres a problem with that laptop. Theres certainly enough threads on the INTERNET about people with problems with their MacBookPro USB ports.

For example...http://discussions.apple.com/thread.jspa?threadID=1032615&tstart=0

However this thread is about charging a HiMD form a home made charger which is a little different no?

[Strungup]

well my reply was about the argument over the USB port on the comp.

As for a Homeade charger

Since your in IT , I think you will have no problem with this one.

4xAA Battery container ( Full enclosure with a Lid type)

a USB circuit mount and associated small circuit board

1 x 8 ohm resistor , 1x 200 kohm resistor , 1 Diode

from Batteries Positive terminal , Diode ->pin 1 of the USB out

Pin 3 & 4 get bridged with the 200 kohm resistor

Pin 4 to the Negative terminal of the battery thru the 8 ohm resistor

6 volts - .7 drop from diode = 5.3 volts

5.3 volts / 8 ohms= 663 ma's

standard USB is 5 volts - 500 ma's

This works for the RH1 , the 200 kohm to pin 3 send a trace current to the Charge sensor of the RH1 and turns it on . This Batt pack will also work for all other MP3 or USB powered devices .

if your needing a little faster charge change the 8 ohms resistor to 6 ohms ( 800 ma's ) 5 ohms gives 1 amp .

Rechargeable batteries 4 x 1.2 volts = 4.8 no need for the diode , just the current limiter

4.8 / 6 = exactly 800 ma's

Edited November 1, 2008 by Guitarfxr

[Sparky191]

....

Since your in IT , I think you will have no problem with this one....

My lack of a RH1 prevents me from trying this. But sounds great.

[Strungup]

My lack of a RH1 prevents me from trying this. But sounds great.

Why does it prevent you from trying it ?

if you have anything that charges from USB then you have reason to do it .

" The Sun isnt out ,.....So I will not work today " .......... Is it raining I ask ?

"It is Winter so I will not walk " ,.......... Do you not have warm clothes ? take some of mine .

[Sparky191]

Sorry I should have said I have no need for it, but it sounds great. No need to mention the RH1 at all.

[samueldilworth]

I'm thinking of getting an MZ-RH1. Could someone definitively confirm all or any of the following:

1. All functions including recording from mic-in can operate while charging from USB.

2. All functions can operate while powered by USB alone, with the internal battery totally dead (though Guitarfxr basically confirmed this elsewhere; thanks!)

3. All functions can operate while powered by USB, with the internal battery physically removed.

4. If recording can be done by USB power, that the signal-to-noise ratio is unaffected.

Merci!

These home-made USB-power devices are fun, but if you're not too handy with a soldering iron you might be interested in the following products, which are the best battery-to-USB power supplies I've seen so far. Sanyo is one of the most experienced battery manufacturers in the market, and their famous "eneloop" AA cells are among the best NiMH cells available. The company can probably be trusted to do things right.

Sanyo call these products "Mobile Boosters". Read about them here, Japanese site here. Of particular interest is that Sanyo specifically mention the Sony MZ-RH1 in their list of compatible products. Three versions are available, all of which supply up to 500 mA at 5 V:

The Sanyo KBC-E1S:

66 x 60 x 25 mm, 55 g (empty), about 100 g (with cells). This model is perhaps the most interesting, as it runs on 2 AA cells so is "future-proof" to some extent (which is my main concern about the lithium-ion battery in the MZ-RH1). Because it's branded eneloop it will certainly work with the lower voltage from NiMH cells, whereas companies like Energizer, etc., may have a vested interest in making their USB-power products work poorly (or not at all) with rechargeable cells. It's also a USB charger, charging the two 2000 mAh AA cells via your computer's USB port in less than 4 hours.

The Sanyo KBC-L3S:

70 x 39 x 22 mm. 70 g. This one uses a 2500 mAh lithium-ion battery (3.7 V) to provide about double the energy of the KBC-E1S in a more compact package. Charges from a USB port in about 7 hours.

The Sanyo KBC-L2S:

62 x 70 x 22 mm, 130 g. A beefier version that uses two lithium-ion batteries, storing double the energy of the KBC-L3S or quadruple the energy of the KBC-1ES (5000 mAh at 3.7 V). Has two USB sockets for charging two devices simultaneously if required. Charges fully from a USB port in 14 hours (!), or via an included AC adaptor in 7 hours.

I don't know the conversion efficiency of these, but it's probably decent enough.

Hope someone finds this useful. I'm looking for one for myself, so I thought I'd share what I found, especially as the MZ-RH1 is specifically listed as compatible in this PDF file.

[Strungup]

The RH1 is on Page 7 of that PDF .

All the ones listed as incompatible , some have a DC input instead of USB , so use a USB to DC cable and the compatibility is then solved.

The bottom one , Wow , 5 Amps , that is a lot of juice , in a small package . I will have to look or that one . and 2 USB ports ,cool , I have a 6 Volt Solar Panel that would go well with that one .

[Strungup]

I like that last one too ... Might look into it sometime. Although the magnesium version of the Solio classic solar charger also tempts me ...

They got a New one ?

Mine got some sun yesterday !!!

[Strungup]

Spammer , it i not the best , TOOBLE works best for You tube and it is FREEEEEEE , so get lost !

[walkdude]

My take on this is:

I can power my MZ-R500 and MZ-N510 from a USB to pin adapter both coincidentally and ironically taken from a Powered USB hub.

My research dictates that my players pull around 3.7 volts around 500mA during boot/playback/record, just enough to run them, but not enough to charge a battery. My PC (and most ones built after may 2006)include the Battery Charging Specification, this means my computer will happily provide 500mA to my devices weither its on, or in sleep/off mode. (which also explains why I only need 1 USB for my 2.5" external HDD)

I can also use two the same cable on this iPod Wall charger which provides 2 USB Ports at 1A Per plug to charge (N510) and run (R500) both of my walkmans at the same time.

[shamrock]

awesome

[topcat36]

@walkdude: I have a MZ-R500, MZ-N505 and MZ-N710. I want to power it from an external charging battery of 5V. Using the cable like you shown in the picture, I power the MD with 5V but the MD has only 3V input rating. I tried to power it for a few minutes but I have the feeling that is getting hot. I just want to know if 3V powered MD's work safely with 5V power supplies.

[Nisei]

I wouldn't use 5V either.
I have made cables for both regular players (just power) and NetMD devices (data + power) that convert the power to 3V.

 

 

 

[Nisei]

 

QUOTE

provided the USB can supply the required current

That is the problem, it can't. Best case scenario you will cause an instability and your system will reboot itself. Worst case scenario you will phisically damage the motherboard or yourself.

What do you mean?

The specs of my original Sony adapters say 3V 500mA, that's 1.5W

A USB port can supply 5V 500mA which is 2.5W

Unless other MD devices are using way more power than the ones I own, USB can supply more than enough power.