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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