AC/DC Power Supply for a marine Stereo Unit

[cb]

I've bought a marine CD/Stereo unit (Jensen MCD5112) to install in a
swimming pool building in Australia and am stumped as to how to choose the
most economical 240 VAC/12 VDC power supply for it and would appreciate any
advice.

The unit is intended to be powered by a boat's 12 VDC system but I have 240
VAC available. I thought the stereo would be a good one for the moist
environment in the pool house.
-------------------------------
Specifications for the stereo are:
Amplifier--
Total System Power 200 W peak
Power Output 4x50 W
General--
Power Supply 11-16 VDC, negative ground
Speaker Output Impedance 4-8 Ohms
Fuse Fast Blow ATO (15 amp)
-----------------------------------------
I planned to connect a pair of indoor/outdoor speakers and can choose
between:
30 W rms, 8 Ohm or 25 W rms, 4 Ohm
The 25 W pair have slightly better sensitivity and frequency specs and cost
a little more.

A label on the stereo unit states, "The amplifiers in this radio are only
designed for use with 4 speakers." I don't know if this means it cannot be
used with just two speakers, or that you cannot connect more than four. I
was only planning to connect two.

My questions are:
1. How small of a power supply can I safely get by with? If I choose the
choose the 25 watt speakers, and find a 80% efficiency, 150 W power supply
would that be sufficient?
2. If the label does mean I need to connect four speakers, can I instead
connect two and substitute appropriate size 4 Ohm resistors for the other
two?

Thanks.

 

[loedown]

Someone finally says first where they are in the world, before asking for
help, well done.

The 4 ohm speakers are the better choice.

I can't see a reason why connecting just 2 speakers would be a problem, but
then again I don't have the unit in front of me, just set the fader control
for just front or just rear, depending which set you connect.

As for power supply, the best would probably be an old AT / ATX computer
power supply, you may have to load up the +5V rail to get it to work, but
they supply +12V at around 8 amps, that's more than enough for this
application and probably the cheapest way around needing an expensive
dedicated supply.

Paul

 

[Art]

Actually any company that does automotive radio repair or even retails the
product should be able to give you a lead to a nice, compact, +12VDC supply.
Even from Radio Shack, however I do prefer the Computer Power Supply
direction only because there are a plethora of them available on the cheap.
Cheers and Have a Great Holiday, Enjoy your Summer Down Under Gov.
"loedown" <zero242@internode.on.net> wrote in message
news:41c92631$1@duster.adelaide.on.net...

Someone finally says first where they are in the world, before asking for
help, well done.

The 4 ohm speakers are the better choice.

I can't see a reason why connecting just 2 speakers would be a problem,
but then again I don't have the unit in front of me, just set the fader
control for just front or just rear, depending which set you connect.

As for power supply, the best would probably be an old AT / ATX computer
power supply, you may have to load up the +5V rail to get it to work, but
they supply +12V at around 8 amps, that's more than enough for this
application and probably the cheapest way around needing an expensive
dedicated supply.

Paul