High wattage speaker circuit

[The Master]

Hi, I got an audio amp circuit to work a while ago using a TDA2030H. Now I want to use 2 bigger speakers together. A 60W midrange and a 100W subwoofer. But i have a few questions.

1) Can/should both speakers be used together on the same amp circuit?
2) If they can then should it be in parallel and how do I calculate the total wattage? (I know how to calculate the impedance for parallel and series)
3) Do pre-made amp chips like the TDA2030H exist that are powerfull enough? The biggest I can find on Rapid is 75W. If not, is there a recommended way of making my own circuit?

[Ioannis]

You can connct them in parallel.

Just make sure the total impedance is not lower than the recommended by he manufacturer of the chip. Otherwise it will get too hot. Also maybe the fail-safe circuits inside the chip (if any) will be triggered.

As for more powerful chips, have a look at the STK series once B&O ued to have in their series of Hi-Fi models.

For example http://www.eleccircuit.com/power-amplifier-with-stk40xx-series-module/

Ioannis

[The Master]

The STK4044 looks like it should do the job. The datasheet is a bit hard to read but it looks like it says that chip can handle 8ohms. I think my speakers are 8ohms so i would only be able to use 1 of them per chip.

I've just been thinking about a power supply. Am I right in thinking that ohms law still applies here? The STK4044 recommends a 51V supply. On an 8ohm speaker I work that out to be 6.375A and 325.125W. So would a 51V 8A transformer do the job? Also, I assume the 325.125W are the peak watts and the 100W specified in the datasheet is the RMS.

On the voltage, is that 51V total (25.5-0-25.5) or does it mean 51-0-51V?

[Ioannis]

For the STK is clear that power supply is symmetrical so +/- 51 volts.

It is an old one but I think it can be found.

Look at Natioanal too as it has some interesting chips too.

http://www.national.com/cat/index.cgi?i=i//286

Ioannis