Electronics > Projects, Designs, and Technical Stuff
Texas Instruments 3116D (ClassD) amp chip
TimFox:
Turning the volume control to 12 o’clock does not mean you are putting out half power.
Look at my earlier response to one of your many posts about estimating your power output and requirements using a CD player.
DW1961:
--- Quote from: TimFox on August 15, 2020, 09:18:44 pm ---Turning the volume control to 12 o’clock does not mean you are putting out half power.
Look at my earlier response to one of your many posts about estimating your power output and requirements using a CD player.
--- End quote ---
I understand that for sure. The point I was making is that the knob is never past a 25-35% when I first hear music. And, that is nowhere near full power because it will continue to get louder all the way to the right stop, when the dial no longer turns. I don't know how many watts it is, but it is nowhere near 50%.
As far as testing how many watts are being used at a specific dial indication, wouldn't it be easier to use a MM connected to the amps outputs for volts and a clamp meter to get amps?
TimFox:
Again, I refer you to my other post. To determine the output power under continuous conditions, you measure the voltage into a known resistance R and calculate P = V2/R.
The volume control is a log-taper gain control. The output power also depends on the input level.
A typical gain control might have a useful range of 40 dB, so half way would be 20 dB below the maximum gain. However, with a “normal” source signal level, the maximum gain may be way too much for the output capability of the amplifier. My good preamp uses a precision stepped-switch attenuator, where the output is shorted at full CCW, with 48 steps. At top center, the attenuation is 24 dB.
tooki:
--- Quote from: DW1961 on August 15, 2020, 05:12:44 pm ---
So, my question, again, what is the benefit of using two 3116D chips when you get the same power output as one chip at 8 ohms?
--- End quote ---
I don’t think there is one, since with the 8 ohm speakers, you’re hitting the voltage limits before you hit current limits.
TimFox:
The conflict between voltage and current limits is why vacuum tube amps use transformers with secondary taps for different load impedance, to get the same power output at different loads. From the tube’s “characteristic curves” one can determine the higher impedance load line (at the plates) that satisfies the voltage and current limits without exceeding the plate dissipation power.
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