Well i stand corrected. It finally went up in smoke. Oh well, it was old anyways. Care to point me into a direction of where i can buy an amp desighned for somthing like this? Thanks again, David
Just for info, the more powerful car amps have a built-in voltage converter to boost the alternator supply up to a much higher voltage, as Wolfe says. From simple Ohms law, a 12V supply can only possibly produce about 15W RMS into 4R speakers, and that's with a double bridged amp (which they usually are). With the engine running you'll get 20W RMS, which is what most car radio chipamps (eg, TDA2005) are rated at. And even with the voltage converter, the 600W PP is sales hype.
Not ressurecting a thread, just adding my 2 cents for info.... Anyone who needs to have a good 12 volt supply for mobile equipment requiring large current should check out an Amateur Radio supplier. Most stock very good quality suppplies designed for just this purpose, since many Amateur Radio operators have mobile equipment and like to use it at home. The shops often carry both linear and switching supplies rated from 10 to over 100 Amps. These are 24/7 power supplies that give clean power, since they are designed for use with radio equipment. Computer PSU's can do the job, but a big enough quality one often cost more than a dedicated supply. Prices vary, but expect to pay about $150 US for a 40 Amp supply
Ok im opening this up again... So this is what i have... i have an old SoundWorks sound system that i bought a few years ago for my computer... turns out the power supply is a 15v kind... Is there any way i can use that to power a amp for my 2 12" subs? Would this also do the trick? >> Link I understnad that a cars batt is rated at 12v... and i have tryed to use a 12v line from a computer PSU but the amp shuts off after a peak "thump" of a song... guess trying to tell me that it doesnt have enough power to produce enough to push the subs... Ill prob buy a mono amp @ about 300w max.... im still looking. David
Couldnt you just use a transformer from ac to 12v dc in whatever amp range you need? They sell them at the hardware store usually for door bell ringers and such. I use these for 12v lights and motors in my house... Your amp certainly has a power suppily you need 12v and at least 2 amp for the trigger need to match up the amp's the amplifier wants with the inverter... Also watch out for the impedance ratings cars usually do 4ohm (these days) and your home speakers at 8... since you say sub's make sure you present the amp with proper ohm m'age... in other words check your sub wiring so you dont end up in "protect" mode at every bump!
care to post some links to these transformers? i cant seem to find any at home depot, lowes.... David
Sorry so long on the reply David... Which this all brings to mind ... Anyone have any ideas how one could rectify an AC transformer into 12v dc? that be even better.... After all CARS ARE AC which are converted to DC (an ALTERNATOR is an AC generator) My thought was this route... http://www.elights.com/kictran.html the K15E60BK is cheap and should fit the bill.... I use a larger unit to power several interrior "mood lights" and a few 12v motors.... Sorry I meant to say lighting and not AC door ringers.... (Ya had me thinkin' of some rectifier circuit using an AC step down) There are many such animals and likely cheaper ones at HD or Lowes: http://www.electricsuppliesonline.com/tr300wa120vo.html http://www.1stoplighting.com/detail.asp?catalog=m3c19s86p37053&source=BizRate&kw=ppc http://www.rockler.com/product.cfm?...word=Deck+Lighting+12+Volt+Transformers++Wire Again sorry for the delay....
HowY: It looks to me that all those links point to products that still are AC. The amp needs DC 12v (to 18v max) power to power it. David
Sorry I thought they were ac to dc 12v converters upgraded to one for my outdoor lighting... You'll need this too... http://www.grainger.com/Grainger/wwg/itemDetailsRender.shtml?xi=xi&ItemId=1611587872 And is what I use here... I started with a typical doorbell transformer but tapped into the lighting circuit and forgot about the power rectifier I already had in line. Sorry my bad... Which just amounts to a set of diodes wired so as to strip out the ac waveform.... And if you can tell I was trying to get someone to chime in on a circuit for just this... (then again these guys mod boxes and I my house!) And remember to wire the sub accordingly... in fact wiring it for higher ohms (8) will reduce the power drawn from the amp. Do I need to digress with wiring multiple coil speakers to obtain 2/4/8 ohm loads?...
You all seem to keep skipping my question.... The power supply has a 15VDC with a 3A. The input is 120VAC 60Hz 0.6A. Would this be ok to use to hook up to the amp? David
do you mean at the same time ?? if so maybe if you play it at a low volume or not at full load if you drive the main amp up to 20 % you still have about 20- 40% of the power avalible however it will run hot maybe or upgrade the psu inside to cope with adding more current use to its load {add bigger rectifer and larger VA transformer and a cap} however i realise its not a stage amp so prob yes just add a fan and a feed to the amp from the back with a fuse rated at 2.5 amp or so usualy these amplifier supplies are dual rail if so youll only get 1.5 amps per rail best to just add a second transformer inside {use a donut torroid type } as for 2x12" woofers best use a small amp design for sub woofers look at this site {very good} ESP AUDIO you can buy pcb from them for some project cheep even complete projects to mount it also inside your amp is your intension i supplose???
Just FYI, 15v @ 3a gives you 45w total. Realistically, any computer speaker system is not going to be able to power a 12" car sub, let alone 2 of them. As far as those projects go, i you know enough to build and troubleshoot them, you can probably already build a simple power supply. I think i found the problem. Your playing rap !
man oh man... every time i read these posts it just confuses me even more than i already am.. OK, here is the amp that i prob will be getting to power the subs: http://store.yahoo.com/wholesaleoverstocks/keka10x2-poa.html Now with that amp above... can i use the 15v power supply from the old sound system to power the amp? If not what can i use to power the amp since the amp takes DC and not AC. I just cant understand how a cars battery 12-15v that an amp uses can not do the same thing when converting AC to DC 12v? David
It depends. power(watts) = Voltage * Amperage. Therefore, Power (watts) -------------- = amperage Voltage IOW, 600 w -------- = 41.6...a 14.4v Essentially, you need a power supply capable of providing about 45 amps ( a little extra for safety). This is either going to require a swithing power supply, (like a computer ps) or a really big ( > 40 lbs) transformer, and some HUGE capacitors. I think your best hope is to look on ebay for something like "12v power supply." In the end, it might be cheaper to just buy a regular mains powered amp.
I do have a computer PSU.. but the 12v lines are so skinny on it.. usualy when you hook up a 12v line in the car from the batt to the amp its about 8ga wire to do so... David
savages {call your selfs modders lmooh } man what are you guys doing in an electronics forum ???? if your not prepaired to build your own equipment and psu's ??? correct me if i am wrong this is a modders forum ???!!!?? so for a start i dont see why it wont power it it maybe able to the guys info is as thin as a skin with nothin in and your calculations are balmy its power = current X voltage {P=I X V} not V X I a small point but important if you work with none whole numbers here is a link for beginners to calculations LINK TO THE POWER WHEEL EVEN THESE AUSTRALIANS GET IT WRONG !!!! HOW EVER THEY ARE UPSIDE DOWN ALREADY SO HAVE AN EXCUSE YOU NOT ALONE M8 you all those projects on ESP AUDIO are concidered beginners grade {1 week in general science to make them } as for psu's well this subject is a farse as i pointed out to the guy it prob wont work hence the reason i sudjested replacing the psu however personaly on this occassion i dont care at all but i dont allow people to try and make me feel somehow smaller than them so dont try this again by quoting me pal just becouse sompeople are stupid enought not to just add a second amp and plug it into the wall you seem to want to try somehow to belittle me for making what is a valuble link on this board to a good reputable audio site for beginners where and when i had already pointed out you can mostly buy full kits / pcb only / or diy it maybe you need to look at the site and not be too crytical as for rap isnt that just jungle music with baked someguy {rap artist} chanting along a load of rubbish somehow trying to look superiour to others becouse he re-itterates what he think's may be important to others in his own way rap is CRAP after the c is used up bring back classical Although there is nothing wrong with a bit of passion, I would suggest you tone down the attitude a bit. If you have a constructive comment to make, make it constructively. Nobody listens to a rant. --Nexxo
as a further point there is no way this amp your on about is 600 w rms 45 amp staic load is more than i have seen used in any car hifi system thats over 900W peek and will need a buss bar and a truck battery to power it best advice is a truck battery and some buss bar and i hope you like tinitus becouse man youll have one sore head
It's a forum for all grades, from total n00b to knowledgeable, and occasionally the knowledgeable have to point out to the n00bs that some wishes can't come true due to hard science. A 45W power supply won't run a powerful amplifier, especially when the OP wants taut bass. Period. One could also point out that putting 12V through a 4R speaker can only generate 36W peak, and that's with a bridged amplifier circuit and zero losses. To get more needs a higher supply voltage, or an amplifier with built-in DC-DC inverter to give the higher supply voltage, which will add extra inefficiency. 12.01 x 3.002 != 3.002 x 12.01 ? Can I ask what you're smoking? And please run a spell-check over your posts.
