I have a class D car amplifier that produces about 1200wrms, (1 Ohm , mono) now have a wife = no car stereo any more so i would like to use it in a home system. So my question is what sort of transformer/ torroid etc do I need (240v Mains)??
TIA, Beau.
TIA, Beau.
if its a really 1200w mono... u need hell lotsa power even if it was 99% effiecent. i think the average class D puts out about 30% of heat.
so....
1200/70 * 100% =~1714w
u need about 1714w.
1714w/12v = 142 Amperes
u need 12v at 142 Amperes. good luck at getting a power supply to suit ur requirements.
on the other hand, i doubt the amp is 1200w RMS. i bet is a mini 100w.....
u`ll do ok with a pentuim4 psu.
so....
1200/70 * 100% =~1714w
u need about 1714w.
1714w/12v = 142 Amperes
u need 12v at 142 Amperes. good luck at getting a power supply to suit ur requirements.
on the other hand, i doubt the amp is 1200w RMS. i bet is a mini 100w.....
u`ll do ok with a pentuim4 psu.
those large woofers some times dip down to 1 ohm... lets play safe... since they are ment to drive 4 ohmz. the likelyhood of them going down to 1 ohm is very high.
I am using 3 Dual 6 ohm subs in parallel= 1Ohm, And the amp has been independantly tested, it came out at 1232wrms AT 14v, 1%distortion.
Re: Re: Power supply question..
Whatever it is, it will for sure not be 1200W continuous. If it was, you'll loose the car doors before the battery runs out. Not to mention the internal cranium heamorrage.
Jan Didden
Matttcattt said:
Whatever it is, it will for sure not be 1200W continuous. If it was, you'll loose the car doors before the battery runs out. Not to mention the internal cranium heamorrage.
Jan Didden
1200w on 50db/w speakers....
plus... do you trust those labs... at 1200w. the internal smps has to be hell of a chunky... i don`t think so...
plus... do you trust those labs... at 1200w. the internal smps has to be hell of a chunky... i don`t think so...
hacknet said:
yeah. 1200w at 12v means 100 amps. Most batteries are rated about 50amp cold crank amps (for a brief period of time), and most alternators are rated 85amps.
Beau what brand of amp is this>???
And since it is a class D amplifier they do not draw near as much as a regular car amplifier....I know this because we did extensive testing on some comp. sytems when we were designing them
Multiple batteries are necessary and premature alternator failure was always a problem until a 200 amp custom wound was utilised
DIRT®
And since it is a class D amplifier they do not draw near as much as a regular car amplifier....I know this because we did extensive testing on some comp. sytems when we were designing them
Multiple batteries are necessary and premature alternator failure was always a problem until a 200 amp custom wound was utilised
DIRT®
hacknet said:
50dB/w speakers? Show me!
And of course you are going to put in those multi-farad capacitors to take care of the current peaks so your smps only needs to be rated at a couple of 100 watts continuously, tops.
Jan Didden
Hi Joe, It is a crossfire CFA1000D, so even if it isnt What it is supposed to be, is there a way I can use it at home?
1200W/1R=34.64V RMS=48.98V PEAK
These are usually bridge amps and run on a maximum of 60V DC, just build a 60V supply for home use.
"And of course you are going to put in those multi-farad capacitors to take care of the current peaks so your smps only needs to be rated at a couple of 100 watts continuously, tops."
AFAIK a 1F cap can only supply 1A for 1Second.
Bass in modern music has close to a 50% duty cycle, so 1200W out means 840W in, and that's driving a resistor with a 100% efficent amplifier.
I would probably use a 42-0-42V 1KVA transformer, 60KµF or so, and 60A rectifiers with a soft start.
These are usually bridge amps and run on a maximum of 60V DC, just build a 60V supply for home use.
"And of course you are going to put in those multi-farad capacitors to take care of the current peaks so your smps only needs to be rated at a couple of 100 watts continuously, tops."
AFAIK a 1F cap can only supply 1A for 1Second.
Bass in modern music has close to a 50% duty cycle, so 1200W out means 840W in, and that's driving a resistor with a 100% efficent amplifier.
I would probably use a 42-0-42V 1KVA transformer, 60KµF or so, and 60A rectifiers with a soft start.
Get a couple of car batteries...charge them up and listen to em?? Guess you would need a hell lot of charging...just to listen to some songs...try a few PC PSUs...down here in Singapore...you can get a scrape NEW one for 5 bucks...10A...so 10 ($50) should give you at least 40A...enuf??
hacknet,
I believe he was suggesting building a simple unregulated power supply and then run that into the amplifier . bypassing the switching power supply thats already in the amplifier.
question for you. you seem to be very skeptical about car audio amplifiers, have you tested some yourself or what ? Not all car audio amplifiers are junk, look around.
I believe he was suggesting building a simple unregulated power supply and then run that into the amplifier . bypassing the switching power supply thats already in the amplifier.
question for you. you seem to be very skeptical about car audio amplifiers, have you tested some yourself or what ? Not all car audio amplifiers are junk, look around.
hmmm...sorry I didn't look carefully enough...I thought he wanted to use the internal PSU as well....he might consider getting a few bigger trafos then...60V??
The clue is in the distortion figures. At 1% distortion I guess almost any Class B amp with a rail voltage over 50V can deliver 1200W into 1 Ohm. Clipping will be included, but only will occur on the peak of a sinus cycle.Beau said:
The trouble starts to deliver this amount of power at a distortion of less than 0.01%.
BTW this amount of distortion would be nice in a tube amp, running 90W Class A or so. Which might produce 720W of heat (@12.5% efficiency) (per channel).
li_gangyi said:
Nice idea: use a car-battery from a diesel engine and a serious charger. I've no idea how much noise this would generate, but a bulky choke and some of those MultiFarad caps might help.
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