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Betty19
Joined: 21 Oct 2016 Posts: 1
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Posted: Fri Oct 21, 2016 8:55 am Post subject: Audio amplifier limiting output power |
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What I have:
• A transformer rated at 150VA / 30V (center tapped) / 5A
• Speaker rated at 30W / 8 ohms (measured 6.3 ohms with my multimeter)
Will use class AB amplifier:
• LM4780 http://www.kynix.com/Detail/1143170/LM4780TA%2FNOPB.html
• Question:
If I send +30V & -30V to this chip, I will get 45W at 1%THD+N:
Is it possible to keep +30V & -30V but limit the maximum power to 30W? Is it by playing with the gain (feedback resistor value)?
I read somewhere "...power amps at lower gains requires more input voltage to get the same power output, with the same speaker impedance".
How to adjust/calculate the gain so that I get a maximum of 30W output with +30V / -30V power supply? I own the transformer already so I plan to use it as the power supply (+30V / -30V). It is center tapped. It is 30V-0V-30V.
I know that sending +40V/-40V is almost at the maximum (recommended) value of 84V. Is it possible to use more diode to drop the voltage or any other method (I didn't found any regulator that fit my needs)? Maybe I can send 40-0-40 but then my output power will be around 82W and my speaker is rated 30W. In this case, I can lower the gain to 20db to help (minimum value) and add a resistor before the speaker (ie: 4 ohms, but very high watt)? I guess I could add a potentiometer at the input (A-B) to limit the power sent to my speaker right?
from the title of the chip, I think I cannot go higher than 60W in stereo: "Overture Audio Power Amplifier Series Stereo 60W". What will happen if sending 40-0-40?!
if sending 40-0-40 to the amp then the output power per channel will be around 82W. What will happen (an implosion or a black hole)?
I am connecting a line out having 16ohms impedance and 1V RMS signal level. What if I add a potentiometer / volume control at the input of the power amp, thus limiting the amount of signal level going in the amp. Would the power amp consume the 80V even if the signal level is only 500mV RMS (ie)?
Any advice would be much appreciated. |
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mahanoor
Joined: 29 Nov 2020 Posts: 2
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Posted: Sun Nov 29, 2020 1:45 pm Post subject: |
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I am building 2x15W amplifier based on TA2024. I am also building small Munny speakers based on 1" full-range Tang Band drivers to go with the amp. The drivers are only 4W RMS and 8W max so the amp is way too powerful for them.
Is there an easy way to limit the output power of the amplifier so it does not exceed the speaker specs? This setup is going to my kids room so I am afraid that they may crank the volume all the way up destroying the speakers.
Thanks. _________________ Here are our reviews of the best toys for 5 year old boys to get as a gift. Check them out. List of best toys and gift for five year boy. |
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Guest
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Posted: Thu Dec 24, 2020 8:50 am Post subject: |
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What can be read in this manual? Are there other more detailed data sheets? |
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Guest
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Posted: Sat Jan 09, 2021 3:24 am Post subject: |
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Is there a standard for the size of the circuit diagram? |
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Guest
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Posted: Tue Aug 03, 2021 2:28 am Post subject: |
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Thank you for your sharing,That's pretty cool. |
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Larry_Dunbar
Joined: 02 Feb 2021 Posts: 1 Location: Minneapolis, MN, USA
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Posted: Sat Aug 07, 2021 12:32 am Post subject: |
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I am building 2x15W amplifier based on TA2024. I am also building small Munny speakers based on 1" full-range Tang Band drivers to go with the amp. The drivers are only 4W RMS and 8W max so the amp is way too powerful for them. _________________ You can buy instagram comments to increase their ammount. |
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Stellalucy0092
Joined: 15 Jul 2021 Posts: 1
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Posted: Sat Sep 04, 2021 12:51 pm Post subject: Electronic equipment repair and service manual search discu |
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You can get L-pad attenuators for 100W. Google "100w lpad" and the first few results should come up that are what you need.
Problem with using L-pads is that they load the device at full load constantly, and thus reduce part life - but if you're using a solid state amplifier this shouldn't be too much of a worry.
Simply get two (one for each channel) and put it a bit less than halfway, adjust to taste. That should kill about 60W from the output. _________________ Puppiespie #1 Plateform That Provide you to Get Best information About Pet, Price and Related Productes (puppiespie) That help to make Your decision. |
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