Determining truth of 555 watt amplifier board

In summary, the conversation discussed the truth of a "555 watt" amplifier board. The math showed that the amplifier actually produces 140 watts at 8 ohms when using +/- 36V, and 555 watts when shorting the output with ground. However, when considering the internal resistance of the IC and using the formula V=IR, it was found that the actual RMS power at 8 ohms is about 140 watts, not 555 watts. Additionally, increasing the output current capability does not affect the RMS power. The conversation also touched on the importance of considering peak voltage and the datasheet for accurate power calculations. The conversation concluded with a question about why the focus was on 8 ohms impedance when the datasheet
  • #1
Tesladude
168
1
Determining truth of "555 watt" amplifier board

My math is showing that this amplifier is not 555watts but 140watts at 8 ohm at +-36v and 555 watts when shorting the output with ground. What do you guys think?

amplifier board:
http://www.ebay.com/itm/High-power-7x-TDA7293-IC-in-Parallel-555W-Mono-Power-Amplifier-Board-Assembled-/121245748119?pt=US_Home_Audio_Amplifiers_Preamps&hash=item1c3acf4b97

IC datasheet:
http://www.st.com/web/en/resource/technical/document/datasheet/CD00001887.pdf
 
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  • #2
The power is always directly proportional to the voltage.
So for +/-36V at 8 ohm we can get theoretical
P_max = 36^2/(2*8) = 81W RMS power. Of course in real life the power will be much lower in range of a 50W ...60W

And if you shot the output, the power dissipated in the amp will be equal to:

Ptot = 36V * 7*6.5A = 1638W (234 per TDA).
 
  • #3
What do you get with all of them in parralel?

I found the internal resistense of the ic at max power, found what it is all at parralel and added the 8ohms and used v=ir and iv=w and got bout 140
 
  • #4
Tesladude said:
What do you get with all of them in parralel?
Current, you increase output current capability.
Tesladude said:
I found the internal resistense of the ic at max power, found what it is all at parralel and added the 8ohms and used v=ir and iv=w and got bout 140
But this is wrong. This 140 has nothing to do with RMS power (continuous power).
To get 140W of a RMS power at 8 ohm you need √(8 * 140) = 33.47V but this is RMS voltage.
The peak voltage is 1.41 times larger. So your power supply voltage must be larger than +/-47.3V
 
  • #5
Ok thanks, I think thatsall I need for now, thanks.
 
  • #6
Why are you fixated on 8 ohms impedance?

555W from 7 chips is about 80W per chip. That is consistent with P0, in table 2.3 of the datasheet.
 

1. How do you determine the truth of a 555 watt amplifier board?

To determine the truth of a 555 watt amplifier board, you can conduct various tests and measurements. This can include analyzing the circuit design, testing the board's components, and comparing its performance to the manufacturer's specifications.

2. What tests should be conducted to determine the truth of a 555 watt amplifier board?

There are several tests that can be conducted to determine the truth of a 555 watt amplifier board. These include a frequency response test, distortion test, and power output test. These tests can help evaluate the board's performance and determine if it meets the advertised specifications.

3. What factors affect the truth of a 555 watt amplifier board?

The truth of a 555 watt amplifier board can be affected by various factors such as the quality of its components, the accuracy of its circuit design, and the manufacturing process. External factors like environmental conditions and power supply quality can also impact the board's performance.

4. Can the truth of a 555 watt amplifier board change over time?

Yes, the truth of a 555 watt amplifier board can change over time. This can be due to wear and tear of components, changes in environmental conditions, or other factors that may affect its performance. Regular maintenance and testing can help ensure the board's continued accuracy.

5. How can you ensure the accuracy of the truth determination for a 555 watt amplifier board?

To ensure the accuracy of the truth determination for a 555 watt amplifier board, it is important to follow proper testing procedures and use reliable equipment. Double-checking the measurements and comparing them to industry standards can also help verify the accuracy of the results.

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