D25S Question
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AssafL

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Just got the D25S from Silicon Salvage. For me it is a reminder that for some reason portable audio has been left with no high end (or mid fi...).

Anyway, I have two questions I hope some of you can help with:

1. Russ Arcuri (in his great review) said that the original Sony Battery is 4 volts 600mAh. As standard rechargeables consist of 1.2V cells, I would assume that the battery is either a 3.6V battery (consisting of 3 cells) or a 4.8V battery (consisting of 4 cells).

2. Is my assumption that the little red 3 way connector (located at the bottom back of the unit) is a recharger connector correct?

I ask this as the Sony battery is quite large. At current technology it should be quite possible to find stick cells that could easily give 1.2-1.6Ah (at 3.6volt) in the available space.
That would increase the portable life 2-3 fold (i.e. 6-12 hours). Also, it could prove to be much cheaper....

AssafL.
 
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meithkiller

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Quote:

Originally posted by AssafL
Just got the D25S from Silicon Salvage. For me it is a reminder that for some reason portable audio has been left with no high end (or mid fi...).

Anyway, I have two questions I hope some of you can help with:

1. Russ Arcuri (in his great review) said that the original Sony Battery is 4 volts 600mAh. As standard rechargeables consist of 1.2V cells, I would assume that the battery is either a 3.6V battery (consisting of 3 cells) or a 4.8V battery (consisting of 4 cells).

2. Is my assumption that the little red 3 way connector (located at the bottom back of the unit) is a recharger connector correct?

I ask this as the Sony battery is quite large. At current technology it should be quite possible to find stick cells that could easily give 1.2-1.6Ah (at 3.6volt) in the available space.
That would increase the portable life 2-3 fold (i.e. 6-12 hours). Also, it could prove to be much cheaper....

AssafL.


1. The original battery (BP-2EX) is just as Russ stated, 4 volts 600mAh. I have one that I got from Sony this year, and have had others (that were old and didn't work). The reason it doesn't follow the current standard of being divisible by 1.2 like normal NiMH and NiCad batteries is because it is lead-acid, not NiCad or NiMH.

2. The little red/orange 3-conductor connection on the bottom of the D-25S is for another optional lead-acid battery, the BP-100. I have two of these that still hold a charge, but one only lasts about 15 minutes, the other one an hour or so. The BP-100 batteries are the complete size of the bottom of the player and clip onto the bottom. They are rated at 6v 1000mAh. These are no longer available from Sony.

Both batteries are recharged by plugging the unit into the wall wart AC adapter in back. Your best bet for portable battery power is to get 9 volts, or close to it (9.6 or 8.4 v) and plugging it in the back power in jack.

-Keith
 
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AssafL

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Thanks meithkiller,

Lead Acid will definitely explain the 2V and the measley 600mAh. Late '80s technology...

I agree that the easiest portable source would be a 9V external battery. However, it can't be ignored that using the battery bay would be very convenient.

As lead-acid has a very steep discharge curve (almost as bad as alkalines), it may be that the d25s will work at voltages as low as 3.6V very well. That is the voltage of Li-Ion cells. All Electronics Corp. sells surplus Sony Li-Ion cells that may fit (I think they are AA size which would fit in the battery compartment if the inner plastic case is removed). Two cells would provide 2.4Ah in the limited space available. That would last 6 times as much as the Lead Acid cells.

Of course that means that the internal charging circuitry could not be used (or will have to be replaced). It may be worth a try...
 
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meithkiller

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Yes, if it would be possible to make something fit in the stock battery compartment, that would be most desirable if compactness and ease of portability is the goal. 2.4 or 3.0 v should work, although it won't likely be as powerful as if a battery with higher voltage was used. Something else to consider is that many other early Sony PCDP's used the 4v battery, but some of them also had provisions in the same compartment to use two AA batteries, my D-303 and D-9 are two such players. The D-303 has the provisions built in to the player in the form of a swinging "arm" with connections for AA batts on it, while the D-9 has a separate adapter that holds two AA batts and removes for use of the 4v lead acid battery. I checked, and the adapter casing unfortunately doesn't fit into the D-25S's battery bay, plus it doesn't have the third connection like the D-9 does for the AA batts.

The only precaution you would probably have to take, is just to remove your homemade battery pack from the D-25S before plugging in the AC adapter, unless you found that the built in charging circuit actually worked with your batteries.

-Keith
 
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AssafL

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Quote:

I checked, and the adapter casing unfortunately doesn't fit into the D-25S's battery bay, plus it doesn't have the third connection like the D-9 does for the AA batts.


That is an interesting point. The red/orange connector does have a third connection point. Perhaps the circuitry is the same as the D-9?

Quote:

The only precaution you would probably have to take, is just to remove your homemade battery pack from the D-25S before plugging in the AC adapter, unless you found that the built in charging circuit actually worked with your batteries.


I would assume the carge circuitry in the D25S is a constant voltage charger (suitable for Lead-Acid). Ni-MH and Ni-Cd require constant current (or some form of current charge), While Li-Ion require a multi stage charging cycle which consists of pre-conditioning (getting the battery voltage to the recommended charging start voltage), switching to approximately 1C charge and concluding with a temp controlled constant voltage charge. So, alas, unless sealed Lead Acid cells are found, I assume the charging circuitry will not be suitable...

Thanks Meithkiller for your input. I will do this later on (as the current project is experiments on balanced power transformers).
 
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JML

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It's probably just easier to get the Radio Shack international AC adapter, the 9V 1500 mA one. It's very small, the plug folds, and it's light. The D25S is not the sort of thing you'll use in a train or bus, or even carry around -- there's no shock protection at all. And it sounds better with AC power anyway.
 
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puppyslugg

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Hi AssafL,

Are you using the d25 as a 'portatble'?
 
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AssafL

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PUPPYSLUG: I use the D25 as a luggable. When I use it at home I usually use it with a Cosmic. Sometimes I take it to elsewhere, as it can drive the Ety's without a problem.

It is for those times I want to get it to be more portable.

JML: Anchored to a receptacle I am very happy with a 9V regulated supply. In fact, my traveller bag is now a hefty bag with three wall warts, 4 D cells, the D25S, a Minidisc recorder, microphone and cabling. Also, I don't seem to be having problems with skipping: I guess the weight of the hefty bag serves to cushion the D25S...
 
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JML

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As long as you're carrying that much stuff around, consider the Radio Shack AC adapter that has selectable output voltage, will charge AA cells, and then act as an outboard power supply and run off the batteries. I posted the reference numbers for it months ago
 
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AssafL

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JML: Thanks. I actually have the RS charger/adapter/DC-DC power bank (used it with the portable Stax with limited success).
I could then use 4 D size NiMH for the Cosmic (I think the current density is 9000mAh), and use the RS as a DC-DC converter to run off the same 4 D cells. Less batteries, less wall warts. Now if the RS can be made to charge 4 D Cells (the RS power bank is horribly constructed and RS do not have a schematic)....
 
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