Hatto
Active Member
I was recently loaned a nice digital oscilloscope to play around with my stereo setup. I've sucessfully set it up to measure stereo amplifier voltage output under load (8ohm speakers) in realtime. My objective is to find the clipping point of my stereo amp under real-world conditions. I determined the voltage output is capped at +-9V (18Vpp). I tried measuring the current output in real-time with a nice multimeter, but I'm guessing I wasn't succesful in doing so considering most I could measure was 100mA.
My first question is, since P = V^2/R: Can one say the amplifier can provide 10.125W (9^2/8) peak power?
I'm trying to find a case where the difference between Vpeak and Vrms is maximum and it looks like this in one of the extreme cases:
In this case, Vpeak (8.60V) = 5x Vrms (1.72V) which means there's 25x power differential between RMS and peak power for this track.
I'm trying to find out, at what point clipping might occur due to a current cap. Now, I know that I can calculate the instantaneous current by using instantaneous voltage and impedance, but I don't have the impedance curve of my speakers.
My second question is: What is a conveniently accurate way to measure the current output of the amplifier in real-time?
As far as I know, impedance rarely dips under the nominal rated value (8ohms) and current draw is maximum when the impedance is at minimum. So I'm assuming the amplifier should be able to supply enough current to support 9V over 8ohms.
Therefore: Is it safe to assume that the amplifier can provide a peak current of 1.125A (9V/8ohms)?
In general I would be delighted if anyone can enlighten me about the error of my ways.
My first question is, since P = V^2/R: Can one say the amplifier can provide 10.125W (9^2/8) peak power?
I'm trying to find a case where the difference between Vpeak and Vrms is maximum and it looks like this in one of the extreme cases:
In this case, Vpeak (8.60V) = 5x Vrms (1.72V) which means there's 25x power differential between RMS and peak power for this track.
I'm trying to find out, at what point clipping might occur due to a current cap. Now, I know that I can calculate the instantaneous current by using instantaneous voltage and impedance, but I don't have the impedance curve of my speakers.
My second question is: What is a conveniently accurate way to measure the current output of the amplifier in real-time?
As far as I know, impedance rarely dips under the nominal rated value (8ohms) and current draw is maximum when the impedance is at minimum. So I'm assuming the amplifier should be able to supply enough current to support 9V over 8ohms.
Therefore: Is it safe to assume that the amplifier can provide a peak current of 1.125A (9V/8ohms)?
In general I would be delighted if anyone can enlighten me about the error of my ways.