Help with a car AMP diy project

[Turtulica]

Hello guys, one of my friends bought a car amp but wants to use it as a regular amp for some home speakers. The problem that we encountered is that we cannot power it on. This is the AMP
I recommended him to get a 12V 8A DC power supply. Like this one
Got all the audio input wiring done and when I pluged it in we realised that we need a power antenna lead? which comes from a car, as it is a CAR amp.
MY question is, can we power this amp without a whole car audio system?

In the manual of the amp says something about 5V to the REMOTE input:
Manual

"The head unit's power antenna lead is logic level
output (+) 5V, negative trigger (grounding type),
or cannot sustain (+) 12V when connected to
other equipment in addition to the vehicle's power
antenna. If any of the above conditions exist, the
remote turn-on lead of your BBX-T600 must be
connected to a switched power source (ignition) in
the vehicle. Be sure to use a 3A fuse as close as
possible to this ignition tap. Using this connection
method, the BBX-T600 will turn on and stay on as
long as the ignition switch is on."

Tell me what you think about this, should he return it, or can this thing be powered from a buck converter or something else.

 

[Diver300]

You just need to wire the remote input to the +12V along with the main +12 V input. So "remote" and "battery" need to be connected to +12V and "ground" connected to the -ve of the supply.

The "remote" input makes integration into a car much easier as whatever switches the amplifier only has to provide a small current. The main power supply can stay on all the time without need to be switched.

In a car, it's important that very little current is taken when the amplifier is turned off. When the amplifier is run from a power supply in a house, the current when turned off is less important, and the whole lot including the power supply can easily be turned on and off with a mains switch, so there's no need for the remote input.

 

[Tony Stewart]

To me it reads +5V or open is off, Ground is ON (negative trigger). Like ignition switch to gnd.

12V will supply 30W to 4 ohms each. 16V will supply 30W peak as advertised into 2 Ohms. but with > 330 W input to include losses. To avoid high temp failures at max power, you need 22A @ ~ 16V in to 2 Ohms per channel and good air flow. So a motorcycle battery and 14.5 charger is another possibility.

 

[Diver300]

To me it reads +5V or open is off, Ground is ON (negative trigger). Like ignition switch to gnd.

12V will supply 30W to 4 ohms each. 16V will supply 30W peak as advertised into 2 Ohms. but with > 330 W input to include losses.

Car amplifiers usually contain boost converters to provide a voltage to the speakers that's larger than the input voltage, so the powers quoted for those voltages don't apply.

The specification for that amplifier says that it contains a DC-DC converter for that.

 

[Diver300]

The power supply is rated at 96 W and won't be sufficient for full volume. However it will probably be fine a lower powers.

 

[Tony Stewart]

The power supply is rated at 96 W and won't be sufficient for full volume. However it will probably be fine a lower powers.

12V/8A= 1.5 Ohm load if your load is this. Load impedance and supply voltage determine the draw current and audio power.

 

[Diver300]

12V/8A= 1.5 Ohm load if your load is this. Load impedance and supply voltage determine the draw current and audio power.

Ok, but the power supply that the output stage of the amplifier isn't 12 V. It is a significantly larger voltage, as there is a voltage converter between the 12 V input and the amplifier power stage.

 

[rjenkinsgb]

12V/8A= 1.5 Ohm load if your load is this. Load impedance and supply voltage determine the draw current and audio power.

It's rated 2 x 70W RMS output in to two ohm loads.
The specs do say it incudes a DC-DC converter.

I'd expect something like a 20A supply would be needed for full power operation.


Re. the aux control input, it looks like the text in the original post should be prefixed with IF..

The first section is for the levels that it cannot work with, and it states to use a direct 12V (eg. ignition) switched power source instead of the radio aux power control, if the radio does not give 12V out as a power control signal.

The main supply could be hard-wired to a suitable PSU, with a low current switch controlling that aux input to switch the amp on.

 

[Nigel Goodwin]

The thing to do is just try it on the 8A power supply, if he's already ordered it - otherwise order a larger one.

But bear in mind that car audio specifications are usually wildly imaginary, although this one actually seems to give real RMS power output Most home speakers though are 8 ohm, so it will only give 25W per channel anyway to 8 ohm speakers, so an 8A supply should probably be OK.

But overall, not a very good idea - you could easily get a proper home amplifier with much higher quality, higher power, and much better facilities. As it is you've got to build or buy a preamp to make it work.

 

[audioguru]

The power ratings are with a 14.4V supply. Its minimum supply is 11V but using a 12V supply is far from 14.4V and is too close to 11V. Does the power supply and wiring provide good enough voltage regulation so that the 12V NEVER drops below 11V?

The stereo outputs are 2 x 50W (4 ohms speakers) or 2 x 70W (2 ohms speakers). The subwoofer output is 130W. The amplifier uses PWM so it is class-D with 10% heating. Then the power supply must produce 297W from 14.4V which is 20.6A for full power from all speakers at the same time.

I never turn up my sound systems to maximum. Then I would use a 14.4V, 10A power supply.

 

[Turtulica]

You just need to wire the remote input to the +12V along with the main +12 V input. So "remote" and "battery" need to be connected to +12V and "ground" connected to the -ve of the supply.

The "remote" input makes integration into a car much easier as whatever switches the amplifier only has to provide a small current. The main power supply can stay on all the time without need to be switched.

In a car, it's important that very little current is taken when the amplifier is turned off. When the amplifier is run from a power supply in a house, the current when turned off is less important, and the whole lot including the power supply can easily be turned on and off with a mains switch, so there's no need for the remote input.

Thank you, I tried your method today and it worked!