TDA2050 10Watt, Power Supply

[lineup]

I will build a gainclone with TDA2050.
Will have 10Watt/8Ohm and approximate 16Watt/4Ohm.

Here is my idea of regulated power supply.
Will use 2x12VAC transformer.

Supply will give around 2X13.0 VDC.

Here is my idea for the positive part of my circuit.
Will be the same for the negative, with LM337 and MJE15031 transistor.

Any opinions are welcome.What capacitors will I need?

 

[lineup]

Here is the correct image attachment.
Sorry for that.

 

[rayma]

Here is the correct image attachment.

See figures 9 and 23 here: http://www.ti.com/lit/ds/symlink/lm317.pdf
Also you need a larger cap at the supply output to ground.
Ensure adequate heatsinks for both active devices.

 

[FauxFrench]

It is a bit just. The LM317 needs a minimum drop of some 2V not to saturate. Then you add a Vbe to the 2V. With 13V out, you need a minimum of 16V in. With loading and ripple, you will go below 16V with that transformer.

I would either use the 2x12V transformer without a regulator or get a 2x18V transformer and use the regulator. 2x18V will allow you to go closer to the 2x25V the TDA2050 can handle.
Minimum of 6800uF for the storage capacitors. 10000uF if you have such.

 

[lineup]

Yes, I think you are right.
A 2x18 VAC transformer is much better.
I might be able to use 2X15.0 VDC for the amplifier.

 

[lineup]

Any thoughts on how big transformer I will need?

My thinking now is dual mono supplies with two 80VA 2x18VAC trafos.
The peak current will be like 4-5A when using a 4 Ohm speaker.

As I said the max power out will be like 16W RMS.

 

[FauxFrench]

Any thoughts on how big transformer I will need?

My thinking now is dual mono supplies with two 80VA 2x18VAC trafos.
The peak current will be like 4-5A when using a 4 Ohm speaker.

As I said the max power out will be like 16W RMS.

The ability to supply peak current is mainly decided by the electrolytic storage capacitors. This is why they are so important.

If "dual mono supplies" means an individual power supply for each channel, 2x18V/80VA is generous. But, for transformers in general: "the more the better" (except for cost, size and weight) and it will allow you to use the same power supplies for another project later on.

Nominally, 2x18V/80VA means 2.2Arms. But, an amplifier feed from a symmetrical transformer (not bridge coupled) pulls current from either the positive or the negative rail. Therefore, effectively the 2.2Arms corresponds to 4.4 Amp in use. Again, the energy to supply current surges op to 4-5 Amp is stored in the electrolytic capacitors. The rating of a transformer is largely decided by the voltage drop from loading and the corresponding heating of the transformer.

 

[lineup]

I have decided to go for supply without regulation.
A guy pointed out that the TDA2050 is well regulated inside.

So, I will use 80VA 2x12VAC transformer.
There will be 2 transformers, one for each channel.

The max output will be like 10Watt RMS into 8 Ohm
and 16Watt RMS into 4 Ohm.

I have 4 Ohms speakers.