AC/DC for a sub. No, wait...
August 24, 2010 1:30 PM Subscribe
My son wants to DJ using a conventional amplifier and speakers, but with his car amp (Pioneer GM-D7400M) powering an 800 watt sub-woofer. This requires a 110 volt wall outlet converted to 12 volts. Can he use a battery charger, or does he need a larger, non-pulsing DC source, like an actual battery or DC power supply? Any other options/wiring tips? TIA.
Can he use a battery charger
No, probably not. And you're right that he'll want a clean source.
The issue here is one of current. Can whatever he's using to power the thing safely source as much current as the amp is drawing?
My guess is that lots of stuff designed to run most car accessories is going to fail miserably at delivering that much current.
posted by Netzapper at 1:47 PM on August 24, 2010
No, probably not. And you're right that he'll want a clean source.
The issue here is one of current. Can whatever he's using to power the thing safely source as much current as the amp is drawing?
My guess is that lots of stuff designed to run most car accessories is going to fail miserably at delivering that much current.
posted by Netzapper at 1:47 PM on August 24, 2010
You are going to want a good power supply. You can find larger ones at amateur radio supply shops. They will supply good clean power. You would be better off buying a new amplifier.
You will probably get hum from a battery charger.
posted by Climber at 1:54 PM on August 24, 2010
You will probably get hum from a battery charger.
posted by Climber at 1:54 PM on August 24, 2010
800 Watts into a 4 ohm load is about 14 amps. It's quite unlikely that you're going to find a DC power supply that can supply 15 A continuously.
The 'cleanliness' doesn't matter at all -- the B+ rail in a car with the alternator and ignition running is about as noisy a power source as they come so the amplifier has sufficient input filtering to deal with it.
posted by Rhomboid at 3:55 PM on August 24, 2010
The 'cleanliness' doesn't matter at all -- the B+ rail in a car with the alternator and ignition running is about as noisy a power source as they come so the amplifier has sufficient input filtering to deal with it.
posted by Rhomboid at 3:55 PM on August 24, 2010
(Er, scratch that.. it's 14 amps at the load but more like 66 amps from a 12V source, assuming it uses a dc-dc converter to get more than 12V required to put 800W into 4 Ohms.)
posted by Rhomboid at 4:01 PM on August 24, 2010
posted by Rhomboid at 4:01 PM on August 24, 2010
With Rhomboid's calculations, I found a 75 amp continuous output power supply. At $450, you are better off buying a nice QSC RMX amplifier. My 2450 works great. Overkill for what he is driving though. The 1450 would be a better fit.
posted by Climber at 7:07 PM on August 24, 2010
posted by Climber at 7:07 PM on August 24, 2010
This (or something along similar lines) should do the trick.
posted by InsertNiftyNameHere at 1:45 AM on August 25, 2010
posted by InsertNiftyNameHere at 1:45 AM on August 25, 2010
25A at 12V is 300W, which is a bit short of enough to power a 800W amp.
posted by Rhomboid at 2:08 AM on August 25, 2010
posted by Rhomboid at 2:08 AM on August 25, 2010
Rhomboid: "25A at 12V is 300W, which is a bit short of enough to power a 800W amp."
You are correct of course, sir. I saw your 12 volt @ 14-15 amp comment and jumped the gun.
posted by InsertNiftyNameHere at 2:45 AM on August 25, 2010
You are correct of course, sir. I saw your 12 volt @ 14-15 amp comment and jumped the gun.
posted by InsertNiftyNameHere at 2:45 AM on August 25, 2010
This thread is closed to new comments.
posted by sanko at 1:46 PM on August 24, 2010