TDA7293 circuit = half wave rectifier

[booj]

Why?

<a href="http://s235.photobucket.com/albums/ee61/myspaceblogphotobucket/?action=view&current=TDA7293circuitcopy.jpg" target="_blank"><img src="http://i235.photobucket.com/albums/ee61/myspaceblogphotobucket/TDA7293circuitcopy.jpg" border="0" alt="Photobucket"></a>

I know the power supply is anemic. I can fix that. I'm new to this stuff. Anybody?? anything??
help!

[booj]

Well, that link doesn't do anything. Lets try something else!

[pikkujöpö]

A voltage doubler ,to get V+ and V- from a single supply.A split supply would be better for a power amplifier.

[booj]

Ok....that pic doesn' load either. Try again?

TDA7293 circuit copy.jpg

See if this works!

[pikkujöpö]

Hi booj

What is it you are asking,could you be more specific.

I can see my answer wasn't very clear either.What you are referring as "half wave rectifier" is called a voltage doubler or voltage multiplier.In this PSU it is used to get V+,V- and GND from a transformer with only two leads.Better solution for a power amplifier is to use acenter tapped transformer or two transformers.there are several ways to do it as you may already know.

[jaycee]

The power supply is silly - it produces +12V and -12V, but at the kind of current a power amp will use it will have excessive ripple.

The configuration of the TDA7293 itself doesnt make any sense either. The best thing to do is read the datasheet - it has a few good example circuits (and pcb layouts, double sided though) that you could use.

[booj]

Thanks so much for your replys. I'm sorry that my circuit is so crappy! It's just a quick throw together type breadboard circuit that I thought should have worked at least enough to improve on.
The reason I don't follow the spec sheet is because although it shows a circuit with all the parts it has the standby and mute going off somewhere with some vague reference to going to V+ through a resistor. Does it or don't it?
And the clip detector goes to Vclip. So what's that?
Guess I should have started with the thread and then built the circuit. I was trying to sort of copy a Marshall AVT50 circuit, which uses a TDA7293 in the output stage. That file is too big to download here. So's the spec sheet on the chip.
If anybody cold help me with the Vclip and the mute and standby things I'd probably be set. The datasheet is easy to Google

[Minion]

Actually the TDA7293 datasheet has a single sided single channel PCB that is useable , I built an amp with it and it worked fine , I suggest you try it ......

a Voltage doubler is whoefully inadequate for a Power amp expecially with the currect demands of a TDA7293 which will probably sag the supply down to +/-10v with lots of ripple ..... I used a 200Va 2 x 28v Transformer for a single channel with 10,000uF per rail and 1000uF at the chip .....




PS: You don"t need to use the clip detector , the Mute feature needs most of those parts to eliminate the turn on thump , it can simply be connected to the positive power rail through a resistor (10K should work) so no seperate 5v supply is needed .....

I also used a TDA7293 to build a Guitar amp (a 100w head) with a tube preamp , sounds great ....

[booj]

Hey Minion,
Is the scat you use exactly the same? I noticed you said a 10 k instead of a 22 k would work fine for getting out of turn on pop. Any other changes?
Also, I'm not trying to get the max power from the chip. I want 30 watts max. Maybe less. I want a "blowproof" design.
As far as the power supply is concerned, what do you do when the ONLY thing you've got is a 12 volt tranny? Huh? Scuse me!
Dude(s)! I can buy a tranny! I can do this! BUT.... I am ignorant to the point of nausea about these circuits! I need help.
So here I am, and this is the latest sketch.
This works.jpg

I think I need a 10 ohm is series with a .22uf to ground on the output. Any other suggestions?
Thanks again guys