How To Connect A Car Amplifier To Hi-Fi Sound!

Necron

Necron

Necron

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Ever questioned yourself if is it possible to connect a car amplifier to your hi-fi? Now here's the tutorial ;)

  1. Get a normal Power Supply, make sure it has at least 15 Amps for a 400W-500W RMS amplifier.

  2. Secondly get the amplifier and make sure you have the labels of the GND (ground), 12V (12V power connection), REM (Remote or also can be labled as MEM).

  3. The next thing is to get a 4 pin molex connector which has 2 ends (4 pin male to 4 pin female or whatever) This is used so that you don't cut the PSU wires and damage permanently the PSU.

  4. Connect the YELLOW 12V line to the 12V socket of the amplifier. Connect the ground BLACK wire next to the yellow wire to the GND socket. Now for the REM, we need to do a loop, just cut the RED wire from the 4 pin molex(or any other wire of the PSU - I used RED to show you) and connect it to the REM socket and to the 12V socket. This is to bypass the connection of the CD stereo used in the car to control the volume.

  5. Now for the input, use male RCA plugs to 3.5mm jack and connect them to the input sockets of the amplifier.

  6. Connect the jack to an MP3 or your PC and you can listen to music.

  7. Connect the speakers using the speaker + and - sockets.

  8. Now we need a small trick so that when the PSU is plugged in and switched on, it switches on. The trick is to find the green wire of the 20/24pin motherboard connection, connect a wire to the green wire and to the black wire near it so that the PSU turns on.

  9. Once you done this, turn on the PSU and the amplifier LED should come RED and then GREEN when voltage has stabilised to 12V.

  10. Now for the final touch, make sure the voltage knob (or volume or sound knob whatever you can call it) of the amplifier is set to minimum as possible, and the audio source to 1 at first. Continue turning the knob of the amplifier volume bit by bit until you hear sound coming from your speakers. Now turn the source volume to full until it is heard normal. Continue turning the volume of the amplifier until you hear distortion. When distortion occurs this means that that's the max it could go as well as for sound quality.

    NOTICE: Make sure you watch the 12V Green LED while you turn up the sound. Seeing the Green LED light dimming or blinking if the volume is turned up a lot is the sign of stressing the Power Supply! Make sure you have a stable green LED which does not blink or dim!!!

Enjoy your car amplifier with your home sound or even your car speakers

NOTICE 2: I'm not held responsible for any loss or damage to any of the equipment or yourself. This is utterly for experimentation purposes and am not responsible. DO IT AT YOUR OWN RISK!

Hope you enjoy the tutorial!

If you need any help or more images, just tell me!
thumbnail.asp


My sound setup:

bgeoo9.jpg
 
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I guess if you had a suitable power supply and car amplifier around it'd work as a sort of ghetto solution, but if you had the money to buy both/either of those things you'd surely be better off buying a second hand integrated amplifier. Interesting guide though.

I'm a little dubious of the claim on that car amp: "pure class A". If it were and it only had the heatsink area shown, you'd be looking at a power output of about 10W per channel at best before the heatsink became scalding hot!
 
A true 400-500w RMS amplifier requires far more than 15 amps @ 13.8V (PS car gear is normally 13.8 because thats the voltage across a car battery thats being charged by the alternator.) Some car amps are measured when running from a 14.4v source to boost the numbers.

That said, the vast majority of car amps are just "fake" numbers, Like amps claiming to be 2000W, but only needing a 20amp fuse... Its simply not possible to get power to the speakers if the power isnt coming in from the supply :) (if the amp contains big enough capacitors it "might" be able to output 2000W for a fraction of a second) IMHO the marketing teams for car amps just invent the numbers out of thin air. They are even worse than the home theatre marketing teams. Probably as bad as whoever decided that Qtek could call there PS Powersupply 600watts :)
 
1. You're Welcome
2. It's just an experiment/cheap solution instead of buying a home amp
3. The amplifier supports from 1-16ohms as said on it's manual and site and is a real 500W RMS amplifier taking 2x30Amps fuses.

Also for everyone saying that sound quality is crap, I've tested lots of music which offered nice crisp clear voice, guitar base, base, etc including:
RnB, Trance, Techno, Minimal, Electro, Indie, Rock, Folk, Pop, Oldies and much much more styles.

About Movies:
Sound quality is great, the voice is crystal clear, the base of explosions and those stuff is also clear, no crippling in sound or that stuff. The watching of a surround movie is a complete awesomeness on this amplifier, and it's not just my idea, I've got several people in my house which listened to it and never complained about sound quality!

Also had the amplifier and sound running for more than 3hrs and the amplifier got only warm, and sound level was average to make the room 'vibrate' :p

Firestar_3x said:
^^^This really.

I wouldn't fancy powering a car amp with the standard super thin diameter power supply cable, enjoy your impending fire.
Click to expand...

For your information, as I said in the topic, it's just for experimentation. And also IF you read the whole topic, I said to watch the 12V LED to not dim, and not having your PSU on stress and explode (if you're saying it that way), and you won't have an impeding fire ;)
So if you don't like or have any interest, just don't post!

P.S.
I've changed the wire and now use high quality sound wire not those 2 whites shown in the pic...
vpb689.jpg
 
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RAM3 MK2 Power Amplifiers

Technical data:
Max. peak music power: 500W
RMS power at 4 Ohm (0,05% THD): 2x150W
RMS power at 4 Ohm, bridged (0,1% THD): 1x450W
RMS power at 2 Ohm (0,2% THD): 2x230W
RMS power at 1 Ohm (0,2% THD): 2x240W
S/N ratio (A-weighted): 105 dB
Freq. response (-3dB): 10-65 kHz
Stereo separation: 70 dB
Input sensitivity: 100mV - 4V
Input impendance: 20 kOhm
Fuse rate: 2 x 30A
Supply voltage: 12 V DC
Dimensions: 230 x 57 x 300 mm


from above specs its 500W peak, 300w RMS at 4 ohm. so roughly 150w at 8 ohms. However I wouldn't be confident with those numbers for a number of reasons. as the PSU side of the amp seems weak, only managing 240w per channel at 1 ohm.

Also it claims to be class A, a pure class A amp making that kind of power would need a massive heatsink to dissipate the heat as already mentioned. My class A amps are like radiators and are one giant heatsink to try and get rid of the heat.
 
According to Signat Products the Ram3 is....

RMS power at 4 Ohm (0,05% THD): 2x150W. With 8 ohm "home hifi" speakers connected you can pretty much drop that to 2x75W (which is plenty to be loud...)

The REM socket isnt a volume control, its simple an electronic on/off connector so the car stereo can power the amp off to save the car battery in a car installation. Volume is controled by varying the voltage on the pre-outs.

A high power CB PSU will be better for running a car amp, as it will output 13.8 volts instead of 12. Car battery + alternator gives you between 13.8 and 14.4 volts normally :P. By running at 12V your probably reducing the amps wattage by around 20%.
 
Necron said:
1. You're Welcome
2. It's just an experiment/cheap solution instead of buying a home amp
3. The amplifier supports from 1-16ohms as said on it's manual and site and is a real 500W RMS amplifier taking 2x30Amps fuses.
Click to expand...

2. Fair enough.
3. No it's not.

Necron said:
About Movies:
Sound quality is great, the voice is crystal clear, the base of explosions and those stuff is also clear, no crippling in sound or that stuff. The watching of a surround movie is a complete awesomeness on this amplifier, and it's not just my idea, I've got several people in my house which listened to it and never complained about sound quality!
Click to expand...

My parents dont complain about low bitrate divx and mp3, but I don't kid myself it's not low quality. Why is surround sound better? Surely a higher bitrate stereo track would be a better choice.

Necron said:
P.S. I've changed the wire and now use high quality sound wire not those 2 whites shown in the pic...
Click to expand...

I think it's the cables from the PSU he's saying are too thin, not the speaker cable.
 
1 molex cable is rated for "just" 7.5 amps on the 12v rail, so really you should jury rid multiple molex cables together so the load is spread over more wires.

Its still a safer bet to get a decent 13.8v CB type PSU.
 
I play mainly 256Kb/s-320Kb/s bitrate mp3's, which are mainly stereo. I also play 1080p hi definition videos on my computer which offer decent 5.1 sound.

I think it's the cables from the PSU he's saying are too thin, not the speaker cable.
Click to expand...

Yes, I know, but I mentioned that to tell that I have upgraded the sound wire and improved a bit in sound performance. Still, all I can say is that the sound is not a low quality one, maybe I haven't heard lots of surround systems, but the sound is absolutely nice. Don't know y r u saying that the sound quality is low using a car amplifier :S

1 molex cable is rated for "just" 7.5 amps on the 12v rail, so really you should jury rid multiple molex cables together so the load is spread over more wires.

Its still a safer bet to get a decent 13.8v CB type PSU.
Click to expand...

Also is it really better to use more than 1 yellow wire for the 12V?


Thanks
 
You realise a car amplifier also has a SMPS, and you're feeding it with another SMPS?

2 PSU's lots of wasted energy, and other nasties.

Also, for the money you spent on a 15A 12Vdc PSU, you could have bought something like a QSC RMX 1850 which will drive 4 ohm loads all day long...

A class AB amp will only be around 50% efficient also, so for a 500W amp, you're going to need a 1000W PSU (20A at least) otherwise you're amp is going to clip, which can result in cooked voicecoils.

I'm not saying don't do it, but I am saying there are better solutions to this 'problem'.
 
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Yes you have a a point, well the PSU cost me nothing since I've just got it for free from a friend of mine heh.
Also what is SMPS?

The problem is that hear in Malta, the amplifiers are really high in price.

Like I bought this Signat amp from a friend of mine for 60eur, the amplifiers are double the price for a second hand 2 channel, and also 4x the price for new amps.

As example of the lowest price of an amplifier from this shop:
http://www.ultimate.com.mt/product_info.jsp?product=147

and another 1, which is quite a gimmick because the output is actually 35Wx2
http://www.tiptopsports.com/electronics-details-91.htm
 
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Necron said:
Also is it really better to use more than 1 yellow wire for the 12V?


Thanks
Click to expand...

if you are going to run that system, then absolutely yes. an amplifier that runs on a 12v supply will need buckets and buckets of current. as Mike said, class AB = 20amp minimum draw for 500w rms output, so you should be using at least 16guage wire (1.3mm conductor diameter, not including the insulation).



I picked up a brand new vibe a4 for £110. that really does manage 1kw RMS output. muchos power for money and it's not a bad amp either :)


edit: actually wait, wait am i saying.....20a is way short isnt it? you're looking at 80 amps at least arent you (80 amps x 12v = 1000watts more or less). i know my vibe packs 3x 35amp fuses (at 14.4v = 1500 watt draw)
 
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good thread, but tbh no point. car sub's/speakers work on most good hi-fi/AV amps, but tbh i didn't know that a car amp would power h-fi speakers because of the ohms being different

im powering 2 500w rms car sub's on a 5.1 AV amp without any problems :p
 
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Necron said:
Also is it really better to use more than 1 yellow wire for the 12V?
Click to expand...

Think how many yellow 12v lines are used to feed a modern graphics card :). If you break open the PSU and look inside you'll find that for each "official rail" multiple 12v yellow wires are simply connected to the same 12v output stage, so joining them back togeter again will simple spread the load over several wires, and prevent overload.

I wouldnt recommend joining 12v lines from different PSU rails. But you can pretty much safely assume that multiple molex power cables from the PSU are all on the same rail. (IE the Rail 1 is commonly ATX+12, Rail 2 for the Molex and SATA, and Rail 3 for PCI-Express). To make matters worse, some 3 rail PSU's are actually 2 rail PSU's with a bit of funky wiring, but only 2 physical 12v regulators.. and some multirail PSU's only have a single BIG rail for the entire PSU, you just dont know without opening the thing up).

Anyway, most PSU's have 3 or 4 sets of wires with molex and SATA power, so it's pretty safe to assume they are a single rail and safe to combine.

You could take all the yellows from the PCI-Express cables instead, that gets you between 2 and 8 12v wires depending on your PSI. a lot of PSU's have an 8 way power connector for the motherboards ATX+12 (technically EPS+12), 4x7.5 amps = 30 amps which will almost certainly be on a single rail from the PSU :).

If your PSU only has 1 rail, you can take and combine any of the 12v power lines without concern :)

A simple non switch mode CB type power supply would still be better, and as they are simple transformers (rather than switch mode power supplies) its a lot less likely to cause problems anyway.

Or you could go "ghetto", and get an old car battery (one that doesnt really cut it for the starter motor anymore), and just recharge the thing every day :)
 
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By the way, is there any reason why your standing your speakers on packing foam? They should either be spiked to the floor, or sitting on a few blobs of blutak (blutak rocks!)
 
Well Actually, just for fun/wear and tear safety? lol. How do you place your speakers on the floor, do you have any floor rubber or something to put under the speakers?

Also thanks for the mini tutorial of the rails of a PSU. Currently I have 2 wires only connected from 2 different rails. I think I have to do more to make it more stable.

Thanks!
 
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