help me in troubleshooting my design

[kavi_e2]

Ωhello guys
iam eletronic student ....currently i doing project with audio amplifier and LED.

i need to design a 0.5w audio amplifier with mute and volume control....the design should allow user to select two different bandwidth....selected choice must be indicated visually using LED...the power supply is +- 12V ...the leval of baseband signal is 250mv pk to pk at 1khz...

components should be used ...MicroA741. TDA7052A, regulator (LM78, L05), transistor 2N2222......

my group was able to design a circuit for our topic...we think there could be some minor faults in ckt.we are supposed to use only 1bandpass filter..and v should not use it for music.now the main problems in our ckt are:

*only two switches must be used,but in our ckt we don't knw which one 2 omit as there are 3switches.

*what is supposed to be done in between the frequency supply and the music's BJT?whether a resistor or some other device to be used there?

*when we test our ckt,do we need to test part by part(op-amp by op-amp)or we can directly patch up the whole things and test for the output?

we have attached two ckt diagrams with this post..the one with red circles was done by us(which is 2 b corrected)
If the other one is more accurate and workable than ours..pls try 2 modify it for us.
pls kindly reply to me ASAP..it would be really helpful if do this favour for us. Thanks in advance

 

[bacterozoid]

Well, if I were doing that, I'd just use an LM386 with a mechanical switch to connect/disconnect the input and a voltage divider/potentiometer for volume...but somehow I get the idea that that's not the purpose of this project

I don't do well with analog electronics in general, but I can answer one question: Test your circuit, as much as you can, separately. Run it through a simulator and your brain and know what to expect at certain nodes in your schematic, then hook it all up to a scope and see if that's the output you get. If you're really (really really really) lucky, the whole thing will work if you just hook it all up and go, but that never happens...for me anyways.

Good luck!

 

[audioguru]

I answered your questions on the other website.
Why are your schematics as big as my entire city?
Why is the second schematic upside-down?