If TDA7294 Can work in 30V AC transformer

[guaxian]

TDA7294 PDF says it max V. is 40V DC, But my transformer is double 30V AC, Will it broken?
Anybody try to use hight voltage in use

[abraxalito]

Yep, you'll definitely blow it up with such a high voltage transformer. Even the TDA7293 which can stand 50V will be a tad marginal with such a transformer, unless its regulation is 7% or better.

[guaxian]

Thanks Abraxalito, But I will still keep trying, If Broken
I will reply here.

[danielwritesbac]

You could use your transformer in Center Tap config with just 2 diodes (total), in the center tap specific full wave rectifier. . . pretty much just exactly like a vacuum tube rectifier.
Link ---> File:Fullwave.rectifier.en.png - Wikipedia, the free encyclopedia
This makes approximately 22vdc,0,22vdc after rectification

or, you could use a regulated power supply

[guaxian]

Thanks for reply！

[vedmitraa]

Hi everybody, This is Vedmitrasharma from City of Tajmahal . Can somebody guide me how to parrellel T D A 7294 I.C.s to get more current power to drive subwoofers as the have done with L M 3886 in Berringer moniter box with 3 I.C.s .regards everybody .waiting for reply

[guaxian]

Originally Posted by vedmitraa

Hi everybody, This is Vedmitrasharma from City of Tajmahal . Can somebody guide me how to parrellel T D A 7294 I.C.s to get more current power to drive subwoofers as the have done with L M 3886 in Berringer moniter box with 3 I.C.s .regards everybody .waiting for reply

I just had TDA7293 with 3 I.C.s. Working fine in +/- 45V!

[guaxian]

Hi all, I have input 30V AC on TDA7294, Working for two weeks,
It's working fine and the TEMP is no hight, TDA7293 may be safe on +/- 42V DC.

[masood]

Originally Posted by guaxian

I just had TDA7293 with 3 I.C.s. Working fine in +/- 45V!

hi guaxian,
can u send me this 3 ic shcematic and pcb details thanks

[ric-paul]

The first three words of the TDA7294 specheet: "ST", "TDA7294" and "100V".
I would have no problem running it on a 2x30V~ transformer.

Infact I did...

I made a PCB for the class G/H application of the TDA7294 and this is in the specsheet as being run of off +/-20 and +/-40. I had a custom transformer wound for it with a 2x30V secondary (and 2x15). It worked for a few months, and then it indeed blew up . But I have no indication the voltage caused it. It had other issues, like clipping at 25V with a +/-20 and +/-40V supply

As for paralleling it: it can be done (there's a commercial amp discussed on here somewhere with (iirc) 12 bridged sets of TDA7294's that can be paralleled to one channel).

But the TDA7293 has a special feature for it (never looked into it as I am stuck with a load 7294's due to the above mentioned failed project) but supposedly it is like a master-slave function and doesn't even need extra resistors. So it would be far easier to do it with a 7293.


Edit: another quote from the specsheet:

The TDA7294 is a monolithic MOS power amplifier
which can be operated at 80V supply voltage
(100V with no signal applied) while delivering output
currents up to ±10 A.