The AC adapter with my computer speakers is broken/dead and I want to
replace it with a new one. The specifications on the dead adapter are
as follows.

INPUT: 120VAC 60Hz
OUTPUT : 13VAC 800mA

If I have to replace it with a new one what are my options. Should I
look for exactly the same specifications or something other will also
work? Do I have to replace it with an AC to AC adapter or can I replace
it with a DC adapter? If I can use a AC to DC adapter what
specifications should I remember.

thankyou very much in advance.

Naveen

On 2 Feb 2006 10:42:49 -0800, wrote:

The AC adapter with my computer speakers is broken/dead and I want to
replace it with a new one. The specifications on the dead adapter are
as follows.

INPUT: 120VAC 60Hz
OUTPUT : 13VAC 800mA

Answered elsewhere. Just get a direct replacement.

Kal

As long as the plug size new adaptor is matches with dead adaptor , 9VAC
900mA, 10VAC1000mA,12VAC950ma will do the job. AC OUTPUT not DC

Best Wishes
Cyrus®

In article wKJEf.2452$MJ.477@fed1read07,
Cyrus® wrote:
As long as the plug size new adaptor is matches with dead adaptor ,
9VAC 900mA, 10VAC1000mA,12VAC950ma will do the job. AC OUTPUT not
DC

You can substitute a DC adaptor for an AC one, but not the other way
around.

--
*Money isn't everything, but it sure keeps the kids in touch *

Dave Plowman London SW
To e-mail, change noise into sound.

On Fri, 03 Feb 2006 15:38:16 +0000 (GMT), "Dave Plowman (News)"
wrote:

In article wKJEf.2452$MJ.477@fed1read07,
Cyrus® wrote:
As long as the plug size new adaptor is matches with dead adaptor ,
9VAC 900mA, 10VAC1000mA,12VAC950ma will do the job. AC OUTPUT not
DC

You can substitute a DC adaptor for an AC one, but not the other way
around.

No. You cannot!
(Only in rather rare situations this is possible.)
--
Kind regards,
Gerard Bok

Gerard Bok wrote:
On Fri, 03 Feb 2006 15:38:16 +0000 (GMT), "Dave Plowman (News)"
wrote:


In article wKJEf.2452$MJ.477@fed1read07,
Cyrus® wrote:

As long as the plug size new adaptor is matches with dead adaptor ,
9VAC 900mA, 10VAC1000mA,12VAC950ma will do the job. AC OUTPUT not
DC

You can substitute a DC adaptor for an AC one, but not the other way
around.


No. You cannot!
(Only in rather rare situations this is possible.)


The old 8 bit Nintendo comes to mind, the original adapter was AC but DC
worked fine as it had a rectifier and regulator in it. Many things that
use AC output adapters do so for a reason though and will not work
correctly on DC, though it's unlikely to cause damage right away.

In article ,
Gerard Bok wrote:
You can substitute a DC adaptor for an AC one, but not the other way
around.

No. You cannot!
(Only in rather rare situations this is possible.)

Please explain why not.

--
*What am I? Flypaper for freaks!?

Dave Plowman London SW
To e-mail, change noise into sound.

On Sat, 04 Feb 2006 23:20:01 +0000 (GMT), "Dave Plowman (News)"
wrote:

In article ,
Gerard Bok wrote:
You can substitute a DC adaptor for an AC one, but not the other way
around.

No. You cannot!
(Only in rather rare situations this is possible.)

Please explain why not.

Well, at first: if DC adapters were for 'universal use' no one
would bother to design / produce / stock / sell AC types :-)

If you supply AC to a device, you can do all sorts of nice things
with the input power:
- rectify it
- rectify it with a doubler (giving + and - for the same voltage)
- rectify it and pull some mains frequency for timing. (Old times
clocks used to do that. Before crystals and digital deviders
became cheap.)
- some loads do not allow dc at all. As several switches don't.
Some motors don't either. In general: if the device is some kind
of coil, don't even think of replacing an AC adapter with a DC
type.

What also counts is the voltage. If an adapter is labeled 10 Volt
AC it is quite easy to pull some 14 volts out of it. (Rectify it,
which yields root 2 times the ac voltage.) You cannot do the same
with DC. (And you cannot replace a 10 volt AC type by a 14 volt
DC type either. :-)
(Please note, that also the load applied may play a rather
important role in the actual voltage an adapter supplies!)

James Sweet mentioned a special case: if the only thing done on
the input is a rectifier, you can connect a DC adapter.
That is: if the device is designed to handle a rather big range
of input voltages and if the rectifier is overdesigned, as in the
DC situation the current through half the rectifier is more than
double that of the AC situation. (Again: with cheap diodes
plentiful in supply, a modern device is likely to handle this
situation. Old devices maybe not. I've seen many 1N4148 'bridge
rectifiers :-)

--
Kind regards,
Gerard Bok

In article ,
Gerard Bok wrote:
On Sat, 04 Feb 2006 23:20:01 +0000 (GMT), "Dave Plowman (News)"
wrote:

In article ,
Gerard Bok wrote:
You can substitute a DC adaptor for an AC one, but not the other way
around.

No. You cannot!
(Only in rather rare situations this is possible.)

Please explain why not.

Well, at first: if DC adapters were for 'universal use' no one
would bother to design / produce / stock / sell AC types :-)

Err, AC wallwarts are cheaper and because of slightly smaller size like
for like may be the answer for some. And of course AC is fine for things
like low voltage lighting. Might also be that a device produced for using
throughout the world makes sense to have the DC conversion and regulation
within it.

If you supply AC to a device, you can do all sorts of nice things
with the input power:
- rectify it
- rectify it with a doubler (giving + and - for the same voltage)
- rectify it and pull some mains frequency for timing. (Old times
clocks used to do that. Before crystals and digital deviders
became cheap.)
- some loads do not allow dc at all. As several switches don't.
Some motors don't either. In general: if the device is some kind
of coil, don't even think of replacing an AC adapter with a DC
type.

I think you're clutching at straws. ;-)

What also counts is the voltage. If an adapter is labeled 10 Volt
AC it is quite easy to pull some 14 volts out of it. (Rectify it,
which yields root 2 times the ac voltage.) You cannot do the same
with DC. (And you cannot replace a 10 volt AC type by a 14 volt
DC type either. :-)

It would be a very poor description and specification of transformer which
supplied 14 volts while being labelled as 10 volts. ;-)

(Please note, that also the load applied may play a rather
important role in the actual voltage an adapter supplies!)

You're missing the point that most electronic devices which use an AC
wallwart will have internal regulation. And the only common one is most
external modems. Why - I've got no idea.

James Sweet mentioned a special case: if the only thing done on
the input is a rectifier, you can connect a DC adapter.
That is: if the device is designed to handle a rather big range
of input voltages and if the rectifier is overdesigned, as in the
DC situation the current through half the rectifier is more than
double that of the AC situation. (Again: with cheap diodes
plentiful in supply, a modern device is likely to handle this
situation. Old devices maybe not. I've seen many 1N4148 'bridge
rectifiers :-)

With any DC device designed to be fed with an AC source you can feed it
with DC - provided you take into account the voltage drop through the
rectifier. And given the poor regulation of most AC wallwarts this is
rather easy to calculate.

--
*If a pig loses its voice, is it disgruntled?

Dave Plowman London SW
To e-mail, change noise into sound.

With any DC device designed to be fed with an AC source you can feed it
with DC - provided you take into account the voltage drop through the
rectifier. And given the poor regulation of most AC wallwarts this is
rather easy to calculate.



That's really not always true, I had an external modem years ago that
would only work properly from an AC output adapter, and a couple
different bubble lamp things and kinetic sculptures that used
synchronous motors and vibrating air pumps, those devices all required
12VAC and would not work correctly from DC. I've built a few digital
clocks that also require an AC output wall wart because they derive the
timing from the line which is much more accurate long term than a
crystal though since those are not a commercial product I can't really
count them.

In article ZnCFf.35724$DV2.17646@trnddc07,
James Sweet wrote:
With any DC device designed to be fed with an AC source you can feed it
with DC - provided you take into account the voltage drop through the
rectifier. And given the poor regulation of most AC wallwarts this is
rather easy to calculate.



That's really not always true, I had an external modem years ago that
would only work properly from an AC output adapter, and a couple
different bubble lamp things and kinetic sculptures that used
synchronous motors and vibrating air pumps, those devices all required
12VAC and would not work correctly from DC.

Yes, but they're not true DC devices if they include an AC motor etc. The
modem should have worked properly - I've used a DC supply for one with
success. But if say its internal electronics have a 12 volt rail the DC
supply will need to be higher for the internal regulator to work, and
regulators fed with a lower voltage than they require can output nasties.

I've built a few digital clocks that also require an AC output wall
wart because they derive the timing from the line which is much more
accurate long term than a crystal though since those are not a
commercial product I can't really count them.

Yes again, but then it's not a DC device. The OP's speakers will be.

--
*If you think nobody cares about you, try missing a couple of payments *

Dave Plowman London SW
To e-mail, change noise into sound.

What also counts is the voltage. If an adapter is labeled 10 Volt
AC it is quite easy to pull some 14 volts out of it.

Many of these ****ty supplies are marked with RMS voltage.
The PEAK voltage however is RMS X 1.414 (X2 for full wave) which
is what appears after being rectified and smoothed. Best to check (if
possible)
the output from the original with a 'scope or meter (a meter measures
RMS)
or better still get a direct replacement.