Car sub Amplifier using a TDA8560Q

[Marcos]

Hello, I am a working in a project of the a subwoofer amplifier for car use, the quality of sound is very good, the subwoofer is double voice coil of the 2 ohms, but when the amplifier clipping the sound it is bad, with snaps...
When the engine in in running, it is very, very bad.
I am use a electrolitc cap of the 4700 uF x 25 volts in paralel with power supply.
What I can make for the trobleshooting the problem?

Thanks to all and excuse me my english.

Marcos

[sidehack]

Is the power for this regulated? Taken straight from the battery, or stepped up with a switching? Is there a filter inline anywhere to cut out alternator hum?

[glen65]

You didnt say whether or not you had a datasheet
on the chip. If not you can get it here..
http://www.ortodoxism.ro/datasheets/...TDA8560Q_3.pdf
They seemed pretty concerned about the way pin 12
should be configured. You might want to have a look and
make sure everything meets thier requirements.

[Eva]

The phenomena thay you describe is probably due to the undervoltage or the overcurrent protections of the chip being activated. That IC is rated at a maximum repetitive peak current of 7.5A, and this value may be easily reached when driving a 2ohm load into hard clipping with the engine on (higher supply voltage). If you measure the DC resistance of the voice coils, you may find that each one has only 1.5 ohms or so.

Anyway, remember that audio amplifiers are not supposed to sound well at all when clipping, and that kind of 12V ICs behave in a particularly poor way when clipping due to the topology employed. Note that these ICs are only designed to drive 4 ohm loads in a realiable way, despite what you can read in the datasheet about 2ohm operation.

Furthermore, since the virtual ground employed internally by the IC is referenced to the power ground, you will have to add a differential input stage if your signal source is not floating and you want to get decent sound without alternator whine (a head unit is not floating while a battery powered a discman is).

[sagarverma]

what ckt have u used?
i have the same ic to power up the midrange speakers in my car.its a nice ic with good power ratings(but low for woofer).
Engine whine was a problem with my whole system in the car.i placed an inductor in between battery positive and the +V input for power (inductor from pc smps).engine whine that increases with the increase in engine RPM,disappeared.try the inductor.

regarding two ohm load driving capability,well this ic drives 4 4 ohm speakers,connected as pairs to give two pairs of net resistance two ohm each and there is no problem at all.
regarding floating ground,i have a cassette player head unit with fm,,for playing the cds i use sony discman.wether its HU or CDP,no effect on sound,its the same either way.

[Marcos]

Thanks to all.

I already also placed a subwoofer of the double voice coil of the 4 ohms, the power is low an the noises and snaps (tac, tac, tac...) they continue...
Many times the problem only occurs with the on engine.
The circuit is power supllyed for the car batery (80 A).
The pin 12 of the CI, is a diagnostic of the clipping, I placed a led for to monitor the clipping, and the problem is occurs only when the led on.

[manyu]

Originally posted by Marcos
Thanks to all.

I already also placed a subwoofer of the double voice coil of the 4 ohms, the power is low an the noises and snaps (tac, tac, tac...) they continue...
Many times the problem only occurs with the on engine.
The circuit is power supllyed for the car batery (80 A).
The pin 12 of the CI, is a diagnostic of the clipping, I placed a led for to monitor the clipping, and the problem is occurs only when the led on.

hello!!! i've the same problem now.... can you post the circuit that you constructed?

[manyu]

can someone give me the circuit that he used constructing his amplifyer with TDA8560Q.. I cant find it on the internet, but the datasheet doesnt help me much :-(

[desertrose]

hi all
i'm new here but i hope find help
i made this circuit with TDA8560Q and it's not work
i tried alote to find the problem but i couldn't
hmm i think the probelm with pin 11 and Pin 12 idon't understand well how to confg it well
and i tried this circuit on 12V not 14v it's diffcuilt to find

iwill be glad for ur help

[pacificblue]

Originally posted by manyu
can someone give me the circuit that he used constructing his amplifyer with TDA8560Q.. I cant find it on the internet, but the datasheet doesnt help me much :-(

Page 10 in the datasheet shows the complete audio circuit. It takes a 470 nF blocking capacitor at each input, a 100 nF capacitor as close as possible to pins 3 and 10 and a 2.200 µF or bigger smoothing cap after the rectifier.

In addition to that you need to connect pin 11 to the positive voltage. Do that through a 10 kOhm resistor to provide a little protection for that input.

Originally posted by desertrose
hi all
i'm new here but i hope find help
i made this circuit with TDA8560Q and it's not work
i tried alote to find the problem but i couldn't
hmm i think the probelm with pin 11 and Pin 12 idon't understand well how to confg it well
and i tried this circuit on 12V not 14v it's diffcuilt to find

iwill be glad for ur help

Same as above. Connect positive voltage to pin 11. If possible through a 10 kOhm resistor. If no voltage is present at pin 11, the amplifier will be muted, and you will hear little or nothing coming out of it.

Pin 12 is not necessary for the function. It provides a signal, if something is wrong. You can connect a LED to it or you can just as well forget it.