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Author Topic: Series-Parallel Wiring My PA  (Read 8861 times)

David Parker

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Re: Series-Parallel Wiring My PA
« Reply #10 on: December 21, 2012, 11:15:09 PM »

Are you suggesting the entire chart is wrong? The 4 ohm bridged number is twice the noted 2 ohm single channel number, and the 8 ohm bridged is twice the 4 ohm single channel number. Exactly as I would expect.

The limiting factor here is the power supply in the amp, there are quite a few amps that put out less power at 2 ohms (or 4 ohm bridged) than at 4 ohms. [I have no direct experience with the MA12K, just saying the chart looks right to me]

Simple mistake... in my greener times I used to wonder why all amplifiers didn't put out twice as much power into 4 ohms as into 8 ohms! Or for that matter 4 x as much into 2 ohms! (not suggesting you think that David)

Cheers!

the 4 ohm bridged rating is less than the 8 ohm bridged rating. That would be very strange if it were true.
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Steve Anderson

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Re: Series-Parallel Wiring My PA
« Reply #11 on: December 21, 2012, 11:37:18 PM »

the 4 ohm bridged rating is less than the 8 ohm bridged rating. That would be very strange if it were true.
Yes… you'll also notice that the individual channel into 2 ohms (3750W) is less than the individual channel into 4 ohms (4500W). Not coincidentally, these numbers are exactly half of the bridged rating into 4 and 8 ohms.

Another example of a well regarded amp showing the same "inadequacies", Lab Gruppen's PLM10000Q can deliver 2300W into 4 ohms, but only marginally more, 2350W into 2 ohms. Driving its sweet spot of 2.7 ohms, it can deliver 2700W.

When an amp is bridged, each channel's load is half the total load impedance.

[edit: corrected bridged loads from 2 and 4 ohms… typo]
« Last Edit: December 21, 2012, 11:43:26 PM by Steve Anderson »
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Mac Kerr

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Re: Series-Parallel Wiring My PA
« Reply #12 on: December 21, 2012, 11:37:45 PM »

the 4 ohm bridged rating is less than the 8 ohm bridged rating. That would be very strange if it were true.

It's not strange, it is in line with the entire iTech line. Power typically doubles when you halve the impedance because the amplifier is delivering voltage, not power. The voltage stays the same, but the current increases through a lower impedance. This holds true till the amplifier can't deliver any more current, at which point the current stays the same and the voltage sags, making less power.

Mac
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David Parker

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Re: Series-Parallel Wiring My PA
« Reply #13 on: December 21, 2012, 11:42:27 PM »

It's not strange, it is in line with the entire iTech line. Power typically doubles when you halve the impedance because the amplifier is delivering voltage, not power. The voltage stays the same, but the current increases through a lower impedance. This holds true till the amplifier can't deliver any more current, at which point the current stays the same and the voltage sags, making less power.

Mac

the oldest version of the peavey CS800 was like that. It did 400 wpc at 4ohms stereo, then dropped to 270 wpc at 2ohms. They said it was current limited. Just seemed strange to see that these days. I stand corrected. I checked the crown website and all the amps in that series were similar. Learn something every day.
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ProSoundWeb Community

Re: Series-Parallel Wiring My PA
« Reply #13 on: December 21, 2012, 11:42:27 PM »


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