which tone control circuit?

[ruleworld]

i want to make tone control circuit for tda2030a amplifer. i use it for listening to fm radio and tv card. i made a tda1524a tone control but it has some noise. so i want to make opamp tone control. which of the following is better?

1. http://sound.westhost.com/project97.htm
2. http://www.runoffgroove.com/tonemender.html
3. (Fig 2) http://headwize.com/projects/showfil...=equal_prj.htm

[kaos]

3

[jaycee]

IMHO, 1... you certainly want a buffer opamp before the tone circuit.

[mlloyd1]

search around here and look for the Apt-Holman preamp tone control circuit. someone posted the manual which contains manual for the entire schematic.
if you have to put in a tone control, this one works well.

mlloyd1

[kaos]

Option 3 fig 2 has a buffer, IC1.

[ruleworld]

thx. i am thinking of making this. similar to no. 3 with single power supply.

http://users.otenet.gr/~athsam/3_band_eq.htm

[ruleworld]

i made this Tone Control on a breadboard and it does not have any noise. the bass is not as good as tda1524a though. and mid range control has almost no effect. the ouput is not very high

can i add this volume control circuit to it with single power supply
(fig 4) http://sound.westhost.com/project97.htm

P.S. I used old c4558 ic i had instead of tl072 / ne5532.

[kaos]

Here’s a link to a National data sheet that shows the math for a simple treble/bass control in the application area of the data sheet. Similar relationships will hold for your circuit as well. You can adjust the values so that the bass will be very pronounced when turned up (if that’s what you want). With a 4558 I don’t think that R10/C8 are needed, though depending on layout, you may need a small value cap (around 33pF) from pin 7 to pin 6 for stability.

http://cache.national.com/ds/LM/LME49710.pdf

The volume control circuit you’re looking at will work with the tone controls when properly implemented. A simpler way would be to just raise the gain of the tone control buffer, either by increasing the value of R2 or reducing the value of R1 (your schematic), and installing a 50K volume pot at the input of the buffer.

[ruleworld]

thanks. adding 100k pot as volume control worked well. no need for volume control circuit anymore. and no need for mid range control too. i am happy with the circuit now.




i have two more simple questions

1. is 4558 is good? i have a few of them and 1558 ic.
2. will a split power supply do a much better job?

thanks

[kaos]

What sounds good is somewhat subjective, someone’s tea is another’s poison. If you’re happy with the 4558 then leave it. If you want to experiment, use a socket and plug in different types of op amps and see what you get. Be aware that some people feel that sockets effect the sound a little bit.

I’m not sure that a split supply will gain much in this application, possibly the elimination of C1 and C11 is all (if the offset is low enough to allow C11’s removal). Getting rid of caps where practical can improve the sound though.