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  #21  
Old 04-23-2010, 01:23 AM
pechinma pechinma is offline
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m_k: thanks for your warnings. i've tried it now though and it does work perfectly. after having read dozens of internet testemonies about using different chargers with success and having asked a technician ("just mind the voltage") i decided to go for it. i guess empirical evidence beats theoretical speculations on this
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  #22  
Old 04-23-2010, 05:09 AM
m_k m_k is offline
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Well, you're welcome, I guess, but I fear I've done you a disservice by posting something that seems to have been unclear to you, so bear with me as I try to clarify things.

Single data points are often interesting, but generally less than useful -- and this, when VALUE of the single data point is known. In this case, the single data point (which I will summarize as "I hooked up my Sansa to a power supply of unknown characteristics, circuit type, or actual voltage, with a label claiming a nominal voltage of a level acceptable to a Sansa, at a current level that is either not stated on the label, or, not shared in my post") -- is devoid of any salient data, other than the fact that the Sansa has not failed in the timeframe beginning with the first use of the power supply and the time that the post was submitted to the forum.

Quite prudent advice your friend gave, to "mind the voltage" -- and quite prudent phrasing, which hopefully was taken to heart. That is to say, he did NOT suggest that you pay attention to the LABEL (which, in an unregulated supply, is a meaningless number UNLESS it is accompanied by a milliamp rating AND the device being driven by the supply DRAWS the SAME level current, AND, the TOLERANCE the manufacturer is using is also known -- a "nominal" five volts, with 20% tolerance, may easily overdrive a voltage-sensitive device even if it DOES draw the "right" number of milliamps).

So, I trust that you have either opened the "wart" box, or, sliced into the cable (to enable you to connect your volt meter to the two power lines), or, located a USB breakout-box and installed it between the power supply's output connector and the player's USB jack, so that you can easily monitor the voltage without having to commit any gross insult to the physical integrity of the power supply.

Otherwise, you really don't know what the voltage is, unless you DO know that it's supply with known-good REGULATION (i.e., one of the known-good switching supply devices sold for use with Sansas).

In any case, since MOS and other LSI electronics are notoriously sensitive to even mild overvoltage conditions, AND will often NOT manifest the effects of a failure mode until some time AFTER the event (i.e., a small area of microscopically-thin insulation may suffer a breakdown -- but not a COMPLETE breakdown at the immediate time of the overvoltage event -- and then, the damaged area will CONTINUE breaking down, even when NOT connected to an overvoltage -- until some time later -- days, weeks, etc. -- it breaks through, creating a short circuit, which MAY cascade into a complete failure of the device.)

My main concern is that others will read what you've posted and conclude on the basis of a single data point SANS VALUE that "gee, it *is* OK to hook up any ol' '5VDC' supply to a Sansa!"
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  #23  
Old 04-28-2010, 08:57 AM
dracheschreck dracheschreck is offline
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I response to those huge posts about data points and whatnot:

If it's USB, it's USB, it WILL WORK, end of the story.

All usb cables / chargers / computer ports comply with very strict specifications and will work with your other USB device, end of story.

This does not apply to some devices which attempt to draw more than what the regulations assume (apple ipad for example)

You will have 0 troubles hooking up your clip to any ol' usb compliant source.
(Then again, this usb compliant source should be trustworthy... any charger from another device of a reputable brand won't give you trouble)
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  #24  
Old 04-28-2010, 12:15 PM
Mikerman Mikerman is offline
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The actual issue can be the quality of the charger. I have had some poor luck with some no-name chargers (and USB cables).
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  #25  
Old 04-28-2010, 12:24 PM
m_k m_k is offline
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Quote:
Originally Posted by dracheschreck View Post
I response to those huge posts about data points and whatnot:

If it's USB, it's USB, it WILL WORK, end of the story.

All usb cables / chargers / computer ports comply with very strict specifications and will work with your other USB device, end of story.

...

You will have 0 troubles hooking up your clip to any ol' usb compliant source.
Awfully thoughtful of you to sign up and leave as your sole post The Voice Of AUTHORITY on the matter. I guess what can I say, but "Yes, Master..."

On the other hand, there's this slight problem I have with "voices of authority" on the Internet that waft in with "don't worry, just DO it" messages.

Funny how they seem allergic to stuff like "common sense" and "caution" (generally cast to the wind).

So, "All usb cables / chargers / computer ports comply with very strict specifications and will work with your other USB device, end of story"?

I guess you haven't heard of this thing called "China" -- or discovered that "what's on the label" ain't always a close match for what's INSIDE THE CASE.

I've seen "USB" stuff (generic wall-warts with a USB connector) that definitely do NOT deliver a REAL five volt regulated output.

If people want to accept the assurances of an anonymous voice that promises them that it's impossible for anything with a USB plug to do ANY harm, then that's their right.

But, for those who CARE about their equipment, well, common sense never went COMPLETELY out of style for SOME folks.
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  #26  
Old 04-28-2010, 01:15 PM
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Both sides of this "argument" are anonymous.

The question the OP posed was a simple one:
Quote:
hi. i wonder whether it's possible to use my old creative zen micro charge adapter to the sansa clip+? the clip seem to have the same usb port as the zen did. i also wonder: does it affect the battery in a negative way to have the clip+ charged for like 12 hrs? i mean can it be overcharged in the sense that it looses some power if it charges "more" than 100%?
As they are both devices running under the same umbrella of charge methods, the Creative charger is fine with the clip or any 5V USB charging device.

No more bloated uselessness.
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  #27  
Old 04-29-2010, 04:29 AM
m_k m_k is offline
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Quote:
Originally Posted by Adub View Post
Both sides of this "argument" are anonymous.

The question the OP posed was a simple one:


As they are both devices running under the same umbrella of charge methods, the Creative charger is fine with the clip or any 5V USB charging device.

No more bloated uselessness.
The Creative charger is likely to be OK; the name-brand devices I've seen, i.e., the Griffin USB chargers, are good quality REGULATED switching supplies.

I take issue however with the "any 5V USB charging device" advice, since I've seen various no-name "China, Inc." wall-warts with a USB connector and a "5VDC" label on them -- warts that are obviously nothing more than a transformer, a diode rectifier, and an electrolytic filter capacitor, and voltage that's all over the place, NOT safe for operating devices that do NOT have their OWN regulation, UNLESS they have sufficient current draw to load down the wart to 5V or below.

I don't think some people are understanding exactly what an unregulated power supply is, or what the voltage printed on the label of an unregulated supply means.

A few minutes with a volt meter will be a real eye-opener for these folks. A "five volt" supply may provide eight, ten, maybe even twelve volts into an open circuit (no load). As the load increases, the voltage drops.

At some point, the load will be precisely the right number of milliamps necessary to bring the supply down to exactly five volts.

Voila, etc.

Of course, if you adjust the volume control, or the battery's charge state changes, the LOAD on the power supply will change -- as will the VOLTAGE it feeds into the device.

And, if the device pulls MORE than the "right" amount of current, the voltage will drop BELOW five volts. This may only result in poor operation, or failure to charge the battery, or slow charge of battery. Or, it may cause damage. (More household appliances are likely damaged by "brownout" (undervoltage) events than overvoltage (spikes, lightning strikes, etc) in the household mains.)

As to both parties being anonymous, this is true. However, one is advising caution, and the other is advising "trust me, go ahead, it'll be fine."

If you can't see the difference in that... then I'm afraid you'll have to find someone else to explain it to you. Sorry 'bout that.

Finally, regarding the "No more bloated uselessness" swipe, I will simply say that if it's descended to "last word, enforced by personal attacks," then I guess you win, buddy. I'm too old for that kinda crap, I'm outta here.

Enjoy your hill, King.
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  #28  
Old 04-29-2010, 12:57 PM
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Quote:
Originally Posted by m_k View Post
The Creative charger is likely to be OK; the name-brand devices I've seen, i.e., the Griffin USB chargers, are good quality REGULATED switching supplies.
Indeed and that is all this thread was about, nothing more.

Quote:
Originally Posted by m_k View Post
Finally, regarding the "No more bloated uselessness" swipe, I will simply say that if it's descended to "last word, enforced by personal attacks," then I guess you win, buddy. I'm too old for that kinda crap, I'm outta here.

Enjoy your hill, King.
You have been defensive and at times on the attack in this thread which is not proper conduct when simply trying to help people. There are no personal attacks here on my part, you went on wild tangents that had very little to do with this thread and i told you to stop that is all.
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  #29  
Old 05-09-2010, 11:38 AM
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Quote:
Originally Posted by m_k View Post
The Creative charger is likely to be OK; the name-brand devices I've seen, i.e., the Griffin USB chargers, are good quality REGULATED switching supplies.

I take issue however with the "any 5V USB charging device" advice, since I've seen various no-name "China, Inc." wall-warts with a USB connector and a "5VDC" label on them -- warts that are obviously nothing more than a transformer, a diode rectifier, and an electrolytic filter capacitor, and voltage that's all over the place, NOT safe for operating devices that do NOT have their OWN regulation, UNLESS they have sufficient current draw to load down the wart to 5V or below.

I don't think some people are understanding exactly what an unregulated power supply is, or what the voltage printed on the label of an unregulated supply means.

A few minutes with a volt meter will be a real eye-opener for these folks. A "five volt" supply may provide eight, ten, maybe even twelve volts into an open circuit (no load). As the load increases, the voltage drops.

At some point, the load will be precisely the right number of milliamps necessary to bring the supply down to exactly five volts.

Voila, etc.

Of course, if you adjust the volume control, or the battery's charge state changes, the LOAD on the power supply will change -- as will the VOLTAGE it feeds into the device.

And, if the device pulls MORE than the "right" amount of current, the voltage will drop BELOW five volts. This may only result in poor operation, or failure to charge the battery, or slow charge of battery. Or, it may cause damage. (More household appliances are likely damaged by "brownout" (undervoltage) events than overvoltage (spikes, lightning strikes, etc) in the household mains.)

[...]
Hi, since you seem to know about the technicalities of this, I wanted to ask something:

Some one gave me one of these AC->usb plugs with the back information printed that it supplies 5v +-5%. I grabbed a multimeter and the voltage reading is always topped on 5.15 with oscillations that make the V drop to 4.90, 5, 5.05, and so on. But the reading always go back to that 5.15 V.

Is this device safe? (I have no clue of electronics or electricity, I had to read on the internet how to use the multimeter).
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  #30  
Old 05-09-2010, 02:48 PM
m_k m_k is offline
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Quote:
Originally Posted by henriquemaia View Post
Hi, since you seem to know about the technicalities of this, I wanted to ask something:

Some one gave me one of these AC->usb plugs with the back information printed that it supplies 5v +-5%. I grabbed a multimeter and the voltage reading is always topped on 5.15 with oscillations that make the V drop to 4.90, 5, 5.05, and so on. But the reading always go back to that 5.15 V.

Is this device safe? (I have no clue of electronics or electricity, I had to read on the internet how to use the multimeter).
Without actually having the unit in hand it's impossible to give a definitive answer, but based on the info you provided I'm hard pressed to see how it could be anything other than a well-regulated switching supply, which is the best type of supply to use with voltage-sensitive devices. The only other caveat is that you did not mention a current (milliamp) rating, and, I don't know the current draw of the device you'll be powering (device+battery charge), so, it IS possible that the device could attempt to draw more than the supply could provide.

A well built switching supply/charger will handle this scenario by going into shutdown mode (rather than dropping its voltage below the specified output). This would mean that if your player tried to pull more current than the supply could safely provide, it would simply shut off -- and inconvenience, but LESS inconvenient than possibly damaging anything via lower voltage or overheating.

BTW, if it seems like I am selectively replying to posts, bingo. I have decided to avoid responding to personal attacks and those who would try to bait me with smarmy insinuations. Life is too short for crap like that. I have a real life. Granted, not much of one remaining to me, but I don't intend to waste any of it involved in that which has metaphorically been summed up in a punchline saying something like "because they enjoy it, and you only get muddy."
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  #31  
Old 05-09-2010, 03:46 PM
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henriquemaia henriquemaia is offline
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Thanks for your reply!

In the meantime, I'll stick to charging it on the computer's ports. The charger/plug has a too cheapish look for me to assume that it's well built and regulated. If this was a more simple matter of knowing if the voltage remains the same, I'll probably would feel a bit more at ease with it, but since it's not, I won't take chances.
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  #32  
Old 05-09-2010, 04:52 PM
m_k m_k is offline
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Quote:
Originally Posted by henriquemaia View Post
Thanks for your reply!

In the meantime, I'll stick to charging it on the computer's ports. The charger/plug has a too cheapish look for me to assume that it's well built and regulated. If this was a more simple matter of knowing if the voltage remains the same, I'll probably would feel a bit more at ease with it, but since it's not, I won't take chances.
Well, the computer's ports are always going to be safe (but on some computers, the front panel ports have reduced current, so it may take longer to charge your battery if plugged into te front), but don't be fooled by the lack of "heft" (for lack of a better term) that is common with switching supplies.

It may seem counter-intuitive, but a cheap unregulated wall-wart will often seem to be better-built due to it weighing more and seeming to be heavier, higher quality.

This is due to the unregulated supply being made with a step-down transformer which consists of lots of copper wire and a stack of heavy (iron) laminations forming the transformer core. Apart from the transformer, which steps-down the house mains to a lower voltage, there is a diode rectifier (sometimes a full wave bridge), and a small electrolytic filter capacitor to smooth out the 50 Hz hum.

The transformer is fairly heavy due to all that metal used in its construction.

A switching supply, on the other hand, takes the mains voltage, rectifies it, and then feeds it to an oscillator that converts the 60 Hz to a fairly high frequency (I think generally in the 40 KHz range). This high frequency AC is then fed to a transformer to reduce it to the lower voltage. The regulation is built into the circuit, so that it will always feed the necessary current to the oscillator to ensure the right voltage regardless of load (within the supply's specified range).

The main thing to consider though, in this context, is that the step-down transformer used in the switching supply will be very small, very light, because of the very high frequency AC it's using. Transformers are more efficient at higher frequencies. The lower the frequency, the larger and heavier the transformer must be. So, the truly cheap wall-wart must be much heavier than the actually higher-quality switching supply.

Generally, when you are accustomed to the typical weight of most common (unregulated) wall-wart type supplies, the first time you pick up a regulated switching supply, it will feel like an empty plastic housing with nothing inside!
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  #33  
Old 05-09-2010, 05:58 PM
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henriquemaia henriquemaia is offline
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Thanks again for your thorough explanation. And that comes as a surprise, because the weight of this unit is almost none. Had I buy it, I would know more about some technical specifications of the unit, but since it was given, I have no clue whatsoever to what's inside or its quality.

Here's a picture of what's printed in its label:

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