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Selecting Power Supply for Car Amplifiers

Last Updated on May 5, 2022 by Swagatam 43 Comments

The following discussion informs us regarding how to select the right power supply for a car amplifier which needs to be operated at home. The questions were raised by Mr. Gyaneshwar Singh.

Questions and Answers Regarding Selecting Car Amplifier Correctly

Question: Thanks for creating awareness on your own concept and resolving problems of others.

I am music lover requiring high bass with soft treble. .

Considering my requirement, I had initially planned to get an amplifier assembled, which would be getting inputs through USB kit having features of FM, Pendrive and Micro-card reader.

But due to feeling lacking a technical person to meet my requirement, I opted and got a Sony Car Music Player (Model No. XR-CA360X) to be used at home (not in car). It can run 4 speakers each of 45 Watts. ( 45 W x 4). On the backside of it, cc 12 volt 10 amp is written while on fuse, 10 is mentioned.

 One electronic shop runner has advised to 12 volt and 5 ampere of quality transformer while sony service engineer has apprised to that the system will use ampere ranging from 5 ampere to 20 ampere on 4 speakers.

I am very much confused. This is why, I am approaching you to extend me your help in term of suggesting me volts and ampere of a transformer or alternate viable option to run the above music system to its optimum. It would be a great help.

Answer: The Sony technician is obviously right and you must strictly follow his instructions, because while selecting a power supply for a car amplifier one must make sure that it has a range higher than the maximum possible consumption from the connected load...in your amplifier the peak power of the music could demand as high as 20 amps, therefore the power supply should be at least 20 amp rated.

A 10amp power supply might also work but that will restrict you to hear the music at lower volumes or you might experience occasional distortions in the music.

Question: :You mean I should opt for 12 Volt and 20 ampere Transformer ? Is it a safe suggestion given by sony person??

One electronic person, who does repairing of car music system, has advised me not exceed above 12 volt and 5 amp otherwise music system would be damaged.

Please make me further clear about above.

Answer: The voltage should NEVER be exceeded above the maximum specified rating of the gadget, that can be fatal!....but increasing current rating will only help to enable the gadget to run at the most optimal level, so in your case current should be 20 amps or as I mentioned earlier it could be 10amp with a compromised listening experience.

So if your amp is rated at 12V/10amp then as prescribed by the Sony technician the power supply should be a 12V/20amps preferably.

Question: You mean high level of ampere is not fatal to gadget.

If it is so (12v and 20 amp), then why fuse of 10 amp is installed. Also, please make it clear.

Answer: yes that's right you can use a 12V 100amp or 1000amp power supply without any fear.

The 10amp fuse is for ultimate protection against a catastrophic situation, in case the power supply malfunctions and its voltage rises or if any of the part inside the amp fails.

Question: For your kind perusal, I have attached manual of Sony music system. You may once again be sure for your recommendation ( 12 v and 20 amp) and suggesting me for:

1- speaker and woofer ( size, watt and ohm and company) for above music system ( 45 W x 4) or I should opt speaker meant by Sony for car.

2 Whether, can I link this music system with 2.1 home theater ( around 30 watt) ?

2- an amplifier for music purpose ( around 200 watt ) wanting two speakers and 1 woofer ( 2.1 home theater) for all purposes. I want high bass but soft high treble.

Answer: My suggestion is technically correct regarding selecting power supply for car amplifiers, and there's no doubt about it.

The manual specifies 12V as the operating voltage for the amplifier, so the power supply should be rated at a fixed 12V (regulated) and the current is immaterial and could be anything higher than 10amps upto infinity.

The speaker power should be preferably rated higher than the max wattage rating of the amplifier.

you can use it with a 2.1 home theater, there's nothing critical about it.

Sorry, telephonic conversation will not be possible due to my busy schedule.

Question: Behind my several questions, there reasons were different recommendations, contradicting to each other. Hope, you will understand my position.

In the light of below mentioned guidance, will you like to add anything related to my case? Your reply will support me.

Please note that Sony Music Company always claim that car music system will not work properly in non-car environment (at home) if I use transformer.

Is it true or only it is stunt to create fear in customer to go for purchasing otter set. Please share your views? Accordingly, I will do so.

Answer: Car amplifiers are extremely efficient units, of course I am referring to the good quality ones.

These may be emitting more heat because these are designed for high bass music, heat and power dissipation are directly proportional to the bass level, and therefore car amplifiers could be notorious for their heat dissipation rate, it's not their fault.

power supply could be a transformer based or SMPS but of a good quality to ensure perfect output.....lower quality could pose problems.

V and I specs will be as specified by me earlier.

A car amp can be operated at home as effectively as in car using a high quality SMPS power supply with specifications as explained by me earlier, however nothing can match the quality using a car battery since these are ideal DC producing devices.

The "stunt" to is to make sure that the amp is strictly used with a 12V source (car batt) and not with non-standard power supplies which could damage the amp and result in higher replacements.

Question: A lot of thanks for sharing your technical opinions. It has been very enlightening for me. After three days of discussion, I have been enabled by you to say below mentioned points seeking conclusive clarification:

1.Car Battery is the most suitable option but very costly (In this situation, Can I use my inverter battery of Exide 150 amp connected with Micro-tek inverter 1025 E Square)

2.SMPS is second preferred option (Can I use SMPS of computer to be purchased from market? If no, which SMPS I need to purchase. Please recommend name of company, which make SMPS)

3.Electric Transformer is third option (Sony Technician has recommended it over SMPS).

4.Can I use 12 V and 5-amp transformer for running only one speaker (instead of all 4 speakers) in low volume for connecting to 2.1 home theater? ( Is it a safe method for both music system and home theater)

Solving the Queries:

1) Car battery can be the ideal choice for all electronic equipment right from a home theater, computer, DVD player, TV set etc. but since we have mains operated equivalent converters at home in the form of SMPS and transformers, a battery is never preferred.

2) It can be an SMPS or a transformer, doesn't make any difference, but it must be a regulated voltage type (fixed voltage DC).

12V 5amp power supply will do if you are using just one speaker instead of the stipulated 4. Assuming your 2.1 has a separate power supply, still there's no harm in feeding the music from it to your amplifier.

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Filed Under: Audio and Amplifier Projects Tagged With: Amplifiers, Power, Selecting, Supply

About Swagatam

I am an electronics engineer and doing practical hands-on work from more than 15 years now. Building real circuits, testing them and also making PCB layouts by myself. I really love doing all these things like inventing something new, designing electronics and also helping other people like hobby guys who want to make their own cool circuits at home.

And that is the main reason why I started this website homemade-circuits.com, to share different types of circuit ideas..

If you are having any kind of doubt or question related to circuits then just write down your question in the comment box below, I am like always checking, so I guarantee I will reply you for sure!

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Reader Interactions

Comments

Fanuel masekaseka says:
December 28, 2023 at 7:36 pm

How are you.
I have a 15v transformer 0.6 ampere,can i use it on a 12v pioneer car radio

Reply
Swagatam says:
December 28, 2023 at 10:25 pm

Hi Fanuel, 15v from the transformer will become more than 20v after rectification, therefore it cannot be used with your 12v radio.

Reply
Mohd Affidi Ali says:
July 26, 2023 at 10:46 am

Why is the over load indicator on, i have installed my car player and the amp for more than 2 years. After 3 months of not driving and starting my car due to air con problems that i just repaired. Recently my player doesn’t work and after checking i noticed that the amplifier shows over load indicator and cut off the sound, how do i overcome this problem ?
Please advice and thank u in advance

Reply
Swagatam says:
July 26, 2023 at 11:38 am

As you may know that sophisticated electronic items can malfunction if not used regularly or is kept idle for many months. I think the circuit may be malfunctioning, and it will need to be diagnosed by opening the amplifier circuit fully. You will have to consult a qualified engineer to repair this fault.
Alternatively you can check the amplifier response by removing or disconnecting the loudspeakers from the amplifier. If the overload indication stops showing it would mean that the speakers are getting shorted somehow and will need to be checked further.

Reply
Shawn says:
May 23, 2023 at 1:00 pm

Hi, I was wondering, couldn’t you just use a car battery and some form of trickle charger. Also would a solar panel powered one work.

Reply
Shawn says:
May 23, 2023 at 1:22 pm

OK, thanks for the feedback but a solar panel would definitely work because all solar is DC anyways, correct.

Reply
Swagatam says:
May 23, 2023 at 1:28 pm

Yes, solar panel will work if its voltage and current specifications satisfy the amp requirement.

Reply
Swagatam says:
May 23, 2023 at 1:16 pm

Hi, At home we can use an AC to DC power supply, no point in using a battery. A trickle charger will not work since the amplifier consumption will be significantly high. A solar panel will work, if it is rated appropriately as per the amplifier requirements.

Reply
David Eakins says:
May 5, 2023 at 9:41 am

Like i said my vehicle had some serious volume with no distortion but I drew a lot of power the cheaper less capable equipment FAILED n I ended up figuring it out as I learned but I would hate to make a mistake n damage my equipment just cause I got the power supply wrong
Any input pls help?

Reply
Swagatam says:
May 5, 2023 at 9:56 am

Please provide the maximum voltage and current rating of your amp, the AC to DC power supply should be also rated with those specifications. The good thing about modern SMPS is that mostly their current output is constant and controlled so your amp cannot draw excessive amounts of current and get damaged.

Reply
David Eakins says:
May 5, 2023 at 9:36 am

Without my cap installed I miss the crisp sharp delivery of bass to my subs but I do know that it draws in amps at high volumes
Does this need a supply with a higher amp rating than just running through a head unit?
I’ve popped 60amp car fuses in the past but I was running 24 sprs 3 amps and had a 2nd battery split charged etc etc
But using my equipment at home on 240v ac is something I have not yet mastered
Would luv some input

Reply
David Eakins says:
May 5, 2023 at 9:28 am

Hi just read the q n a I am also trying to convert my old car audio to a home dj set up I understand all the above criteria but I have a car audio capacitor which is wired from source to sub amp to sub would that work from 240v inverter or would I need separate supply for my sub element as it is the dump valve for my bass

Reply
Swagatam says:
May 5, 2023 at 9:53 am

Hi, I could not understand what you meant by ….”I have a car audio capacitor which is wired from source to sub amp to sub…”

To operate your sub amp with a 220V supply you simply have to use a regulated AC to DC power supply which must be rated according to your sub amp spec. There’s no other criticality involved.

Reply
Dan says:
September 13, 2021 at 7:15 am

using a gaming computer power supply output with 12v 20A or 30A for car stereo is Good.

Reply
Dan says:
September 13, 2021 at 7:09 am

Use A gaming computer power supply with 12volts output 20A or 30A for your car stereo.

Reply
Asegai says:
July 11, 2021 at 4:52 pm

Good work. keep it up!

Reply
rtrg says:
January 28, 2021 at 6:16 pm

can a 12volt dc 2 watt power supply power a 12 volt dc 20 watt audio amp?

Reply
Swagatam says:
January 29, 2021 at 9:51 am

yes it can power

Reply
Divyarajsinh Rathod. says:
March 29, 2019 at 2:50 pm

Hi, Swagatam.

This is Divyarajsinh Rathod from Ahmedabad (Gujarat).
I have JBLE250P powered sub woofer that I was using at my home.
But before few days the back plate AMP burnt, also when i approached the JBL service station for the replacement amp for it, they told me that the model is out dated and no replacement plate for this model availabe now.
So if you can suggest me what should i do. One of my friend told me to use the car audio amp with computer smps, but i doubt that it wont give enough current(amps) for the sub and car amp.

The help which I want is, Is there any proper ready made plate amps for this sub indian made available, or is there anyone who can make on demand.
If not than shall i go with the car amp, please suggest me the proper power supply for it.

Thanks.

Reply
Swagatam says:
March 29, 2019 at 3:09 pm

Hi Divyarajsinh, I don’t know much about plate amps so I won’t be able to suggest much, but you can surely use a car amp instead. For the power supply you can easily buy a 12V/20 amp SMPS from amazon at less than Rs.1500/-

Reply
KAANAAVIL says:
November 21, 2016 at 6:18 pm

Why you cant use 12V 30 Amp led power suplay For car audio ? Its low price also.

Reply
Gyaneshwer says:
February 3, 2016 at 11:37 am

I am talking about computer SMPS only.

Reply
Swagatam says:
February 3, 2016 at 3:08 pm

Check it with a multi-meter, that's the correct way of proceeding

Reply
Gyaneshwer says:
February 3, 2016 at 5:21 am

There are several yellow and black wires in SMPS. whether I should use all or particular one plug which has two yellow wires and one black wire.

Reply
Swagatam says:
February 3, 2016 at 11:14 am

I won't be able to confirm that without seeing practically, I think you should talk with the dealer from where you purchased it.

Reply
Gyaneshwer says:
February 2, 2016 at 5:36 pm

Yellow wire of SMPS is 12 volt therefore yellow ( as mentioned on PCB) and black wires, need to be used.

a black cable with 3 pin plus comes for SMPS and green wire is not visible inside the black cable.

Reply
Swagatam says:
February 3, 2016 at 5:17 am

It's important to check from where these wires are terminating…look for the (+) and (-) symbols around the SMPS connectors and integrated the wires accordingly…or you can also use a multi meter for verifying the same.

if green wire is not provided at the input side of the SMPS then simply don't use it, and anyway since your amp does not have a green (earthing) wire so you can just forget about it

Reply
Gyaneshwer says:
February 2, 2016 at 9:36 am

but how to know whether a car music system has a compatible earthing wire with its cord??

Reply
Swagatam says:
February 2, 2016 at 1:30 pm

I think it won't be there since there would be just a (+) and a (-) to connect…so ignore the green wire, use only the red and black outputs from the SMPS.
at the AC input side make sure to use the green wire, with a 3-pin plug

Reply
Gyaneshwer says:
January 31, 2016 at 2:35 pm

Thanks

What about green wire of SMPS. whether it is to be liked with any material like speaker or other material.

I have arranged two computer SMPS of Hipro and Zerbanoics companies. Is their any comment on these two SMPSs.

Today, I had seen two sony car speakes each of 150 watts and 4 ohms. Will these speakers will work properly with sony car music syste of 45watts x 4.

Reply
Swagatam says:
January 31, 2016 at 4:03 pm

green wire is the earthing wire, use it only if your amp has a compatible earthing wire with its cord, otherwise just leave it.

all reputed companies are reliable, you can use any of those.

150 watt speakers will work, but according to me the speaker wattage should be on par with the amp wattage rating, hence a 70 watt speaker will perhaps work better with a 45 watt amp rather than a 150 watt speaker.

Reply
Gyaneshwer says:
January 29, 2016 at 2:35 pm

I am finally recommended to use a transformer of 12 v and 20 amp with output of 240 watt.
Now, I need to connect this transformer with music system of 180 watt (45 watts x 4 speakers).
If I want to use one pair speaker wires (45 watt) with home theatre, what would be effect on both music system and home theatre, as music system would be bearing an input of 240 watt through the transformer.
In other words, whether one pair speaker wires (having flow of 240 watt ???) would damage both the music system and home theatre as the power (240 watts) of music system would not be full exploited through this arrangement.

Reply
Peter says:
February 23, 2022 at 8:53 pm

Good,insight.can I use a laptop powersuply rated 15v 4amp to car radio?

Reply
Swagatam says:
February 24, 2022 at 10:43 am

Yes you can, if your amp is also rated at 15 V.

Reply
Swagatam says:
January 29, 2016 at 3:05 pm

where exactly do you want connect speakers wires…is it from from transformer DC to the music systems? please clarify on this.

Reply
Gyaneshwer says:
January 30, 2016 at 5:36 pm

Have you made any powerful amplifier circuit, which give high bass and high but soft treble. I want it for home purpose.

Reply
Swagatam says:
January 31, 2016 at 7:01 am

bass and treble are determined by additional filter circuits included with the amp….I have tried the following design and was quite happy the results

https://www.homemade-circuits.com/2012/04/how-to-make-simplest-100-watt-mosfet.html

the circuit can be used to achieve upto 400 watts by suitably raising the voltage upto 100V

Reply
Gyaneshwer says:
January 30, 2016 at 5:35 pm

Your reply on your website does not send alert to the question raiser. Please do needful.

Reply
Swagatam says:
January 31, 2016 at 6:58 am

other readers have never complained about this issue and it seems they are all getting the alerts from here….make sure you tick the "notify me" box before posting the comments.

Reply
Gyaneshwer says:
January 30, 2016 at 5:34 pm

I want to one speaker wire ( instead of 4 speaker wires) to home theater

Please recommend rating of speaker wire.

Whether in computer SMPS, before linking with music system, I need to add further any diode etc.

Reply
Swagatam says:
January 31, 2016 at 6:55 am

divide the expected peak wattage by the supply voltage which the wire is supposed to carry….. you will get the current rating for the wire, add 10% more to that figure.

Reply
Swagatam says:
January 31, 2016 at 6:56 am

diode will be already persent inside the amp, so no need of adding any further diodes.

Reply
Swagatam says:
January 29, 2016 at 3:26 pm

if the wire is not adequately rated it could get warm and restrict optimal output power from the amplifier but that would have no adverse effect on the systems.

Reply

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