High-power TDA7293 555W ?

[zorkwan]

High Power TDA7293 IC in Parallel 555W Mono Power Amplifier Board Assembled | eBay
7*TDA7293 PARALLEL 555W


is it worth it?
i want to buy one just to analyse it with my college professor,,thats why im asking,,shoud i buy it or do you recommend me something else?

 

[abraxalito]

To get that level of power output from the specified 35V rails you'll need a fairly low impedance load, not your usual 8 or even 4 ohms. What is there to analyse?

 

[zorkwan]

To get that level of power output from the specified 35V rails you'll need a fairly low impedance load, not your usual 8 or even 4 ohms. What is there to analyse?

So you mean that to gain that power I need to use 2 or less ohm at the output..analyze the difference between class D and standard transistor amplifier.

 

[JimBeam69]

It's very simple:

Prms=(Udc)^2/(2*R)

Prms:The absolute maximum output Power you can get from a BTL Class D amp without clipping
Udc:Your DC supply Voltage(Here we have +-35V=>70V)
R:Your Speaker Impedance

It will actually be a bit less (times 0.9 or so) because of things.

 

[theAnonymous1]

TDA7293 is a Class-AB chipamp.

 

[JMFahey]

True.
But that is the least of the problems.
That EBay offer is absolute nonsense design, it's ludicrous.
7 amps in parallel will demand 1/7th output impedance load, 0.57 ohms speaker in this case.
Good luck finding one.

Plus supply filtering is also wrong; they have 4 x 2200uF caps, they need 14 ... nuff said.

Just another proof that the Chinese Industrial and Commercial system is the best in the World:

**ANY** Chinese, no matter how unqualified (this "design" is proof enough) , can make any product, no matter how cheesy or poorly made and sell it to the World in exchange of good old US Dollars.

Need more proof that uneducated buyers fall for it?
It's straight in the EBay ad:

Seller : laserlands (22937 sales) About laserlands
99.4% Positive feedback
Get fast shipping and excellent service from eBay Top-rated sellers.
More than 10 available / 13 sold

 

[Marcelo Gustavo]

This assumption it is not correct.

Each amplifier needs to deliver only 1/7 of the loudspeaker total current.

 

[zorkwan]

Well..i just bought the L25D ..and i think i did the right thing after searching in this forum

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[Pafi]

This assumption it is not correct.

Each amplifier needs to deliver only 1/7 of the loudspeaker total current.

"This"? Which?

1/7 of the current of 7 paralleled 4 ohm speakers, otherwise 550W will never be delivered. And you may know: 1/7x7=1...

 

[Marcelo Gustavo]

I have done my post in response to the post made by JMFahey.

(7 amps in parallel will demand 1/7th output impedance load, 0.57 ohms speaker in this case. Good luck finding one).

 

[Pafi]

I know. But which "assumption"? The load impedance? It is not an assumption, but result of calculation, and your statement is not denying it. Or the difficulty of finding 0.57 ohm speaker? Why? Have you seen any?

 

[Marcelo Gustavo]

Pafi:

The amplifiers are in paralell not the load. The calculus is incorrect.

 

[Pafi]

How do you think the load can take the full power if it is not paralleled multiple speaker? Do you know the equations P=V*I, I=V/R?

 

[Marcelo Gustavo]

Pafi,

Do not get me wrong, I'm not trying to offend you.

But I'm not willing to discuss basic theory of circuits.

Sincerely, Marcelo.

 

[zorkwan]

You never know how Chinese people think!!

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[Pafi]

Pafi,

Do not get me wrong, I'm not trying to offend you.

But I'm not willing to discuss basic theory of circuits.

Sincerely, Marcelo.

As you wish. But you started (the discussion about a very basic question). The statement you denied is based on basic theory of circuits only.

 

[Pafi]

From datasheet for those who don't like math:

Parallel mode is possible by connecting several
devices and using pin11. High output power can
be delivered to very low impedance loads.

(And I quess the designer of that board didn't know the difference between "several" and "seven"... )