Audio Amplifier Project question

[Thisisme]

Hi guys,

I'm trying to build an audio amplifier with tone control for one of my circuit design courses. I'm supposed to use either the lm833 or the ne5534 opamp to provide a gain of 10 and supplying maximum power to a resistive speaker load, upto 20 khz. The circuit should also be able to boost the treble and bass and provide attenuation up to 10dB before being fed to a speaker.

I have no idea about how to go about building this circuit. I got a hold of the lm833 datasheet, from here:

http://cache.national.com/ds/LM/LM833.pdf

and it has a circuit for tone control. But I'm not sure if it will do everything that I've been asked to do, or how to modify it to suit my requirements.

I'll be very grateful if anyone could provide any tips or hints on how to go about this, because I have to complete this project as soon as possible.

Thanks in advance.

Dev

[Khron]

The tone control schematic in the datasheet seems to be just what you're looking for; you'll just have to tailor the component values to suit whichever frequencies you'll want to boost/cut.

And regarding the attenuation... Wouldn't that be simplest to do with a pot, or a stepped attenuator? And i do hope that resistive speaker has a considerable resistance, because this poor little chip can't dissipate a lot of heat without burning up in the process

[davidlzimmer]

This chip will serve as a tone control only. It will boost and cut both bass and treble. You can use the values on the schematic. One circuit per channel.

But, this will have to feed a power amp that will deliver 20 watts at 20khz to meet your project requirements as you expressed them. Also, depending on the input signal level, you may need a preamp stage.

You might seek advice in the chip amp forum since you sound like you are in a hurry.


Don't jump on me guys! He didn't specify the amp had to be a discrete.

[Leolabs]

Well then get a LM1875 as the power amp task.

[ttan98]

Leolabs,

where do you live in Bukit Mertajam? it must be hard for you to get good quality parts over there...

I am an ex-Penangnite...now I live in Melb., there you go.

[Leolabs]

I usually go to Jalan Kampong Benggali near the NBCT.

[ttan98]

I am not so familar with B.M.

Buy via post, you can pay now via Paypal, much cheaper transaction cost. Postal charges are the killer.

with US dollar dropping you must find parts getting more expensive? good for exporters and not for importers.

any chance of ringgit revaluing?

[Leolabs]

Don't mind about the price as long as it's worth the price.Do u have any MSN contact???Sounds like we are hacking Thisisme's topic here.

[ttan98]

I am not working, are you?

don't let your boss catch you on the net?

sorry I don't have MSN. you can email me the address can be found using my profile if you like.

signing off...

[Thisisme]

Thanks a lot for the help guys! Are there any any power amps that I could use besides the LM1875? How do I decide which is the best power amp suited for the job?

Also, about the attenuation, would that go in the tone control stage or the power amp stage?

Thanks again!

Dev