The damping factor was better than 275 into a 4-ohm load. Into a 1-ohm load, the damping fell to just better than 60; still acceptable.
Signal-to-noise ratio (SNR) was good at 100dB, A-weighted just below clipping; and efficiency at full power into 2 ohms was 54%, about average for a class AB amp. At 1/3 power the efficiency fell to 30%, a bit lower than we like to see.
Idle current measured only 1.1 amps, very low for this power class. At low power, the amplifier should remain at a cool operating temperature.
Finally, the input sensitivity had a nice wide range, variable from 160 mV to 4.5 volts. The CE1000M should have no problem making full power with any source unit.
Listening TestBecause this amplifier is monaural, we conducted our listening tests on our subwoofer system only. We confirmed our electrical tests, indicating that this amp should introduce no sound of its own when driving such a system; thus no coloration or distortion could be detected. The bass response was solid and reasonably accurate. There was, however, a slightly noticeable turn-on thump and a turn-off thump.
ConclusionThe CE1000M is very powerful and is cleaner then its class D counterparts. With 1,220 watts of power, a variable subsonic filter, 24dB/Octave crossover, variable bass boost and remote level controller, this amp should meet the audio enthusiast's requirements.
FeaturesFull range mono, bridgeable with a second CE1000MLow pass internal crossoverRemote gain controlBass boost controlSubsonic filter
A Word About CapacitorsIn the automotive environment where internal operating temperatures easily exceed 100 C, high quality 105C capacitors are a big plus to ensure the longevity of the amplifier. In high current areas, such as 12 volt filtering and the power supply output stages, low ESR (Equivalent Series Resistance) capacitors should be used as well. Low ESR capacitors not only do a better job of filtering, but run cooler. Capacitors have an electrolyte, and can easily be destroyed by high temperatures.
DampingDamping is simply the amplifier output resistance specified as a ratio of this resistance divided into the load resistance. For example, an amplifier that has an output resistance of .01 ohms (perfect would be zero ohms), and rated into 4 ohms, the damping would be 4/.01 = 400. The ability of an amplifier to actually dampen cone motion is degraded by the speaker's own internal DC resistance. A typical 4-ohm speaker may have 3.2 ohms of resistance. So, in this example the damping could not exceed 4/3.2 = 1.25 regardless of the amplifier's damping.
ProsHigh powerRemote level controlCan drive 1-ohm loadsBridgeable with a second CE1000M24 dB/Octave crossoverMechanically stackable
Cons85 C. capacitors in power supplyLow slew rateInternal fusesOnly fuse protection for speaker short protectSlight turn-on thumpTurn-off thump