Mukhalled Posted October 27, 2004 Report Share Posted October 27, 2004 hiCan this circuit work at 12V input?http://www.electronics-lab.com/projects/audio/027/index.htmlThanx :) Quote Link to comment Share on other sites More sharing options...
audioguru Posted October 28, 2004 Report Share Posted October 28, 2004 Hi,This amplifier is designed for a 32V supply, so certainly won't give much power output with only a 12V supply.10W into 8 ohms is a voltage swing of a little over 25V peak-to-peak.So the voltage loss in the circuit is a little more than 7V. If you have the same voltage loss with a 12V supply, the output is only 5V peak-to-peak. That is only 391mW into 8 ohms or 782mW into 4 ohms at clipping.Since the output voltage swing is reduced, the output current will also be reduced, so the voltage loss will probably be only 4V. The resulting 8V peak-to-peak will give 1W into 8 ohms or 2W into 4 ohms at clipping. Quote Link to comment Share on other sites More sharing options...
Mukhalled Posted October 28, 2004 Author Report Share Posted October 28, 2004 Thank you :) Quote Link to comment Share on other sites More sharing options...
Mukhalled Posted October 28, 2004 Author Report Share Posted October 28, 2004 but how can I do if I want to connect this amplifier to a car stereo I mean you know the car battery has 12V so shall it give a bad output power?I need your help :) Quote Link to comment Share on other sites More sharing options...
audioguru Posted October 29, 2004 Report Share Posted October 29, 2004 Hi again,You can't use this amplifier in a car unless you also use a DC to DC step-up converter to get plus and minus 18V. Most very high power car amps do it this way, and use many strong output transistors so that they can drive a very high current into a very low impedance (1 or 2 ohms). Since Power = Voltage X Current, they increase the voltage and the current and therfore have a high output power.A trick that many "ordinary" car amps use to increase the voltage is to use 2 amps for each speaker, wired as a bridge, with each amp driving 1 wire of its speaker, out-of-phase with the other. This results in nearly 4 times the output power. Most car amps are also rated to drive a 4 ohm speaker, into which they can deliver nearly 2 times the power than an 8 ohm speaker.Some car amps even use low-loss Mosfets to increase their output power.The most output power that an "ordinary" car amp can deliver to a 4 ohm speaker is about 25 Watts, at only 1 middle frequency, at 10% distortion and with a 14.4V supply. They are usually advertised as "50 Watts maximum power" (per channel, the 4-channel amps are advertised as "200 Watts").I am sorry that I can't find a good car amp for you now. Maybe another of our members can help you or maybe you can find a car-audio forum on the web. Quote Link to comment Share on other sites More sharing options...
audioguru Posted October 29, 2004 Report Share Posted October 29, 2004 Look what I found:A car radio amplifier IC that gives 24W into a 4 ohm speaker:http://www.semiconductors.philips.com/acrobat/datasheets/TDA1516BQ_1.pdf Quote Link to comment Share on other sites More sharing options...
Mukhalled Posted October 29, 2004 Author Report Share Posted October 29, 2004 Thank you so much for your answers :) Quote Link to comment Share on other sites More sharing options...
Giuflex Posted November 6, 2004 Report Share Posted November 6, 2004 U can search a schematic for a car amplifier with tda 1562q. this circuit should give U 70watts RMS (thet's what the manufacturer says)This link should help U a little http://www-us.semiconductors.philips.com/acrobat/datasheets/TDA1562Q_ST_SD_2.pdf Quote Link to comment Share on other sites More sharing options...
audioguru Posted November 6, 2004 Report Share Posted November 6, 2004 Hi Giuflex,That's a tricky IC that uses a supply voltage-doubler. Its channels are internally out-of-phase so that mono bass doesn't load down the voltage-doubler too much, another neat trick.Watch out about what the manufacturer says about power output. They guarantee only 45W at clipping, for a low-spec one that may have been made late on a Friday. Some ICs might produce 70W, but at a horrible-sounding 10% distortion (turned-up too much giving square-wave output). The power ratings are with a 14.4V supply, which is too high for a normal car battery, and without the voltage losses of a fuse and supply wiring. Quote Link to comment Share on other sites More sharing options...
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