Ah! Great explanation!

There would be no problems using lower voltage than +/-18V ? Lets say 12-0-12V?
Is that just "bolt on" on the circuit? or does the capacitors and resistors has to be adjusted?

Best Regards,
Olof

Hey again,

there is no problem using a transformer with a lower output voltage. 12Volt AC is ok too. Then the amp is supplied with 18Volt DC. But, this will decrease the output power. If you don't need the ~30 watt output power per channel, you surely can do it.

You wrote about a transformer with 12-0-12 Volts AC. This is a centre tapped transformer. As said - i would go for a "dual secondary" transformer. With a "centre tapped" transformer you must change the Power supply circuit, because the circuit from the project page is designed for use with a "dual secondary" transformer. It is not a big problem to change the PSU circuit, but you'll have to know how...

The transformer is hooked up to the Power supply circuit.
Please take a look on the "supprt page". There, you'll find some useful informations about the connections and wirings.
TDA2050 Project Support Page

I'm working on some further descriptions...

Hi again, just let me ask one more questioN!

How do I know if it's a centre tapped or dual secondary?

https://www1.elfa.se/elfa~se_sv/b2b/cat ... ab=catalog Are you able to see if this a centre tapped or dual secondary transformer? Sorry it's a swedish site but I think you get it

It says 2x18V so it should be a dual secondary? But it doesn't say anything if it's AC or DC. Or is it allways AC?

By the way, the complete amp circuits should be connected in parallel like this right? With the same GND point?

Hej,

Yep - 2 x 18VAC is a "dual secondary" transformer. That will say, that the transformer has 2 windings with 18Volt AC per each.
One with 18-0-18 is a centre tapped transformer with 18Volt AC from the outer leads to the middle (centre). The centre always is the "ground". Transformers are always rated in VAC. VAC is the short form from "Volt - Alternating Current".

You're right with your drawing. That's the way to connect the PSU (Power supply unit) to the amp.
As said - the amp connection is discussed on the Support page...

Transformers are always rated in AC.

Please try to contact "tjolle62" or "Soundbrigade". They should be glad to help you out with a source for transformers in Sweden.

Thanks again,

I got offered a 80VA 18Vx2 dual secondary transformer VERY cheap. If I choose to go with that one is there anything that has to be adjusted to the PSU and amp circuits?
I know it will affect the sound negatively, but since it's my first project I doesn't have to be "top of the line".

sorry for the bother, that was my last question!

Thanks again,
Olof

Hej Olof!

IMO - I hope that you'll stay

That's a great deal! There is nothing to adjust (even not with lower voltages or other VAs). Now - the 80VA is a bit low, but the only result is a little bit less power. The rest will be "as tested". Don't worry about it! The amp isn't meant to be a top level project. The project should show, that it's possible to build a good amp (yep - it is!) without to study electronics or to spend hundreds of bagis.

Take it ez and take you the time you need to get the stuff together. Feel free to ask if there is something you want to clear up.

Skål!

Hej,

You don't happen to have a PCB layout of the "Figure 3: DIY TDA2050 Hi-Fi Amplifier Schematic" ? or would you prefer soldering it on a photoboard? Didn't you waste a lot of solder?

Skål! I really mean it, 18 years old today!

Happy birthday Olof!