This is a technical question so I'll try to answer it in technical terms.

As I think you're understanding it, yes.
However, "wattage on the wire" is a strange thing to say. The power drawn by the speakers when the amplifier is set to its full output is the same as the sum of the tap wattages of all the speakers, modified by the volume control(s) and gain structure to the actual wattage being output at the moment.

With exactly the same wiring and tap settings, when the volume is all the way down, NO wattage is drawn, so no "wattage on the main speaker wire" is present. When the output volume is, say, 10 dB below the power amp's maximum specified level (70 volts), then the power drawn by the speakers is 10 dB below their tap value. In the example you give, this would be 6 watts output.


Nothing rides on the line. If you had no speakers connected to the amp, and you turned up the amp, then a voltage could be measured on the line but no current would flow so no power would be output. Is that "riding on the line?" I don't know.

But you ask:

If you have 4 sats, each tapped at 15w, and you turn up the inputs to the power amplifier such that its output reaches 70 volts, at that point 60 watts would be being drawn by the speakers, so yes. (We always overlook that at lower volume control settings, there's lower or even zero output.)


What tells you that you need to add another speaker line suppressor? Could the same thing be accomplished by moving the one you have, for instance to the point where the wires leave the house?


I only see literature on one model, the 250 Watt TPD-AmpPro, at [Link: cdn-docs.av-iq.com]. Before going on about 70 volt operation, let's note that it says it is designed for

This changes how we should view these details.

A 70 volt amp reaches its maximum (clean) output level when its input level makes it output 70 volts. The amount of power drawn depends on the amount of load connected to it. Yes, the sum of the taps gives you that figure.

A power amplifier designed for use with four ohm and eight ohm loads is not designed to deliver such a high voltage. It is designed instead to output a much higher amount of current. 4 and 8 ohm loads are MUCH higher loads (lower resistance*) than most 70 volt loads!

Ohm's Law formulas are given below for reference. The lower one in pink says that voltage equals the square root of the wattage times the load. From this, we get that the output of a power amplifier that's feeding 250 watts to an 8 ohm load measures 44.7 volts. A power amplifier that's feeding 100 watts to a 4 ohm load measures 31.6 volts.

This means you're hoping to use a device the manufacturer targets for use with a maximum of 31.6 or 44.7 volts. You're going to use it with 70 volts.

Now, the sheet also says that the Maximum Operating Voltage is 100V RMS, which is more than twice the 44.7 volts of 250 watts into 8 Ohms. With a 70 volt amp, this is a lower safety margin than they design for, but it might be okay.


The amp puts out 70 volts (I hate to keep repeating, but it puts out 70 volts only when it's at full power). The 250 Watt unit lists a maximum operating voltage that is 100/44.7 times the higher voltage that it's specced to work at. If you used the unit with 1000 watt rating, that should increase your safety margin enough. I only found the data sheet on the lower power unit, so I can't come up with any actual numbers on this.

You should call the manufacturer and ask about these things.









*yeah, yeah, I know, impedance.