hi
i have an old 4 channel amp, i used only 2 channels till now
now i have decided to dedicate other 2 channels to a sub
can any 1 tell me a simple method to calulate the Rms wattage of my system. i just need an aproximation, i have 2 multimeters, the amp n few 4 ohm speakers a PC with winISD freq. generator with me
any great Ideas
i have an old 4 channel amp, i used only 2 channels till now
now i have decided to dedicate other 2 channels to a sub
can any 1 tell me a simple method to calulate the Rms wattage of my system. i just need an aproximation, i have 2 multimeters, the amp n few 4 ohm speakers a PC with winISD freq. generator with me
any great Ideas
Drive you amp with pure sine wave. If you don't have frequency generator, just use the sound card.
You can download the software at
http://www.nch.com.au/tonegen/index.html
Load the amp with 4 or 8 Ohm high power resistor, or nichrome wire heater
Set the multimeter to AC, measure the output of your amp (with power resistor connected).
For example, if measured voltage is 15 VAC, (loaded with 4 ohm resistor)
then RMS power @4 ohm is 56.25 Watts
RMS Power = (V*V) / R_Load
= (15*15) / 4
= 56.25
You can download the software at
http://www.nch.com.au/tonegen/index.html
Load the amp with 4 or 8 Ohm high power resistor, or nichrome wire heater
Set the multimeter to AC, measure the output of your amp (with power resistor connected).
For example, if measured voltage is 15 VAC, (loaded with 4 ohm resistor)
then RMS power @4 ohm is 56.25 Watts
RMS Power = (V*V) / R_Load
= (15*15) / 4
= 56.25
One thing to watch out for!
Hi darw82,
You must use approximately 50 ~120 Hz as a test signal. Unless you are using a good Fluke or new Agilent hand held meter, higher frequencies will be inaccurate.
Most digital voltmeters have very poor high frequency response. 1KHz is already out of range for them.
-Chris
Hi darw82,
You must use approximately 50 ~120 Hz as a test signal. Unless you are using a good Fluke or new Agilent hand held meter, higher frequencies will be inaccurate.
Most digital voltmeters have very poor high frequency response. 1KHz is already out of range for them.
-Chris
Hi,
without a scope to check when the onset of clipping is ocurring, you will need an attenuated output fed to a speaker so you can try to monitor the distortion due to the clipping. Not accurate but it will give a clue.
Alternatively, measure the PSU supply voltage and get an estimate from that.
without a scope to check when the onset of clipping is ocurring, you will need an attenuated output fed to a speaker so you can try to monitor the distortion due to the clipping. Not accurate but it will give a clue.
Alternatively, measure the PSU supply voltage and get an estimate from that.
- Status
- This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.