Another tda2030 question

[pimster987]

I just recently built a single supply tda2030 amplifier and I was wondering what are the benefits of using a split power supply (+- voltage). I tried to look it up but all the results that come back are splits +12V or +5V rails. I know you can use lower values in components but I dont know exactly why. Could someone please provide me some reference.

[jackand08]

By using a dual supply (say +/-15V), it allows the amplifier output at idle, to stay at 0V instead of being at around 1/2 supply voltage (in single supply) which means that a DC blocking capacitor is needed on the output to block the DC offset but allow the AC audio signal through.

There are many problems with having a capacitor on the output of any amplifier as these components, regardless of quality and price, will always detriment the sound quality of any amplifier (just by varying degrees depending on what capacitor is used). The capacitor also causes a roll-off in bass response if its value is too small but using a higher capacitance value will affect high frequency response and will mean needing a physically bigger capacitor.

Using a dual supply, it does away with the need for this capacitor and therefore the deterioration in sound quality that results. It also allows the amplifier to output its full power as stated in the datasheet as the output now has (with a +/-15V supply) a 30V rail-to-rail swing whereas a single supply with +15V only has a 15V voltage swing.

[pimster987]

Thanks that cleared up some things for me. I have one more question. I understand what all the components in the circuit do except for two capacitors. What does the 22uF capacitor and 2200uF capacitor do? I understand the other caps are bypass and decoupling caps and the .1uF is part of the zobel network. The circuit I am talking about is figure 1 (single supply amp).

http://www.st.com/stonline/books/pdf/docs/1459.pdf

[Minion]

The 2200uF cap is the DC blocking output Cap , in a dual Supply version this cap would not be needed ..... The 22uF cap is used on the Voltage divider that is used to referance the input to half supply , I believe it helps keep the referance voltage stable , this and the two 100K resistors wouldn"t be used in a dual supply version ........