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RE: Atmasphere MA-2 impedance question

At 60 ohms the MA-2 does loose some power but its not a lot. Above about 5 ohms, the amp is on a linear curve where power is decreasing very slightly as impedance is increased, such that at 16 ohms the amp makes the same power it does into 4 (we are only talking a couple of watts here). The limitation is the voltage in the power supplies of the amp, but essentially what happens is into the higher impedances the output section also gets more efficient- more power dissipated in the load and less into the power tubes. So on a Sound Lab the MA-2s (and MA-1s) tend to run with less heat, with no trouble making bass power, something that is a problem with many amps, especially transistor amps (although transformer-coupled tube amps can be challenged by the impedance curve as well).

The result is that the MA-2 can make the same volume on the speaker as transistor amps rated at 600-800 watts.

The Sound Lab mods that have been a topic on this forum seem to really help the amp out, regardless of the amplifier technology. Customers that have MA-2s and Sound Labs that have done just the resistor mod alone report that they essentially have unlimited power- its not possible to clip the MA-2s. That means that the actual panels themselves must be fairly efficient- well into the 90s by equivalent 1 watt/1 meter measurement.


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