Audio Amplifier

[The Master]

Sounds like a good idea. Ill order some of those chips with my next order from Rapid and start messing with them.

Thanx for your help

[Ioannis]

The LM386 is a low power chip (0,25w@8 ohm, 1w@32 ohm) and has many flavors according to the drive load impedance and power supply. Choose carefully, according to the speakers ohms. Do not choose an LM386 driving 32 ohms if your speakers are 8! You will loose many milliwatts.

If you finally select this one, provide adequate earth on the PCB as this is what cools the chip.

I believe it is not suited for the case... Choose a stronger chip as Luciano suggested.

Ioannis

[The Master]

Hmm, looks like this is about as difficult as finding the correct PIC chip :P

I went back to Rapid's site and found a TDA2030H 14W HI-FI POWER AMPLIFIER (RC). The datasheet says "12W on a 4W load" so im sure that would be enough. The datasheet even gives a PCB layout design (I can read those better than schematics).

Just incase you think theres something better heres the list i have to choose from Audio power ICs. There are more powerfull things on there but i dont want to waste money buying 75W amplifiers for 5W speakers. 20W is probably about right because im not sure exactly what the speakers are

[skimask]

I had my numbers backwards the whole time.
I really meant to indicate the LM383 (8W), not the LM386 (which is more suited for driving headphones).
Yes, LM383. The datasheet has a schematic in there for setting up a pair of them in a 'push-pull' configuration to get a 16W amp.
But, as stated earlier, make sure you have a decent heatsink on it, for that matter, any chip you chose, otherwise you'll spend the bulk of your time in 'thermal overload shutdown' and eventually you'll start killing chips.

[The Master]

I think the best thing to do is order a few of the chips on that page and all the external components i need for each one so i can experiment a bit. I should probably dig out some old speakers and an old mixer too so i have better control over the volume and if something breaks it doesnt matter much.

Its a good job i know about the heat part. Normally if a chip even gets slightly warm it means ive done something wrong. This chip is obviously different and heating up is normal.

How do i put a heatsink on a chip? Is it as simple as just putting it ontop and securing it to somewhere else on the PCB to hold it on? Ive got some thermal paste for CPU heatsinks, should i put some of that on? What size heatsink should i use (roughly). Will one thats about twice the widthe of the chip, a little longer and about 1cm tall do or would i need really big ones? Theres going to be a fan or 2 in with it anyway so that should help

[Melanie]

Go with your own suggestion of the TDA2030... it's a standard TO-220 'style' package and Rapid have stacks of Heatsinks that will do the job.