Hi Mojo and all,

We've got a new spec to post on the A1400-8 amplifier from Axiom's R&D engineer, Tom Cumberland. The spec is called "DC Offset," which many manufacturers simply won't post on their amplifiers because the DC offset may be excessive.

For the Axiom A1400-8, the DC offset is truly tiny, approximately 0.0001 volt--that's one-ten-thousandth of a volt, a fraction of the value that many conventional amplifiers often exhibit.

What's DC offset? It's really interesting. The power supply of any amplifier has to deliver a positive voltage and a negative voltage from the power-supply rails, but often the voltage is offset a bit to one side or the other--too much negative voltage or too much positive voltage. In theory, the power supply should deliver equal amounts of positive and negative voltages; in reality, there may be more negative (or positive voltage) from the supply rails. When this happens, and you have your speakers connected but there is no audio signal, the offset voltage will force the driver's voice coil either slightly outwards or inwards, away from the center of the magnetic flux from the speaker magnet. When this DC offset goes uncorrected, this means that the excursion of the voice coil will be non-linear. When high-amplitude audio signals come along, this may mean the voice coil is forced out of the magnetic flux because it's already offset from the excessive amounts of DC offset, so the motion of the voice coil and diaphragm becomes very non-linear.

The great thing about the Axiom A1400-8 is that the DC offset is 1) extremely low in value (other amps may exhibit ten to 20 times as much DC offset as the A1400-8) and 2) the A1400-8's DC offset is dynamically self-correcting so that no matter what the value of the incoming audio signals, the DC offset will be minimized to an insignificant value at all times, thus assuring the linear motion of all the drivers' voice coils driven by the A1400-8 amplifier.

We'll have some more charts and specs next week.

Regards,


Alan Lofft,
Axiom Resident Expert (Retired)