The ATI Morris Kessler Signature 4000 Series amplifiers, available with 2 to 7 channels, share the design philosophy and circuit sophistication of ATI’s award-winning 6000 Series amps with power output reduced to 200W RMS per channel at 8 ohms and 300 W RMS at 4 ohms. Furthermore, their “signature series” designation with a facsimile of Kessler’s signature on the main panel attests the special nature of these amplifiers.
Beyond Kessler’s personal identification, these amplifiers share these key features with the 6000 Series Signature amps.
1. Fully balanced, differential amplifier design with two output stages per channel but with only a single input stage. The advantages of balanced designs are retained and noise is further reduced by 50%.
2. Current feedback instead of the more common voltage feedback. The reason: current feedback amplifiers are faster with virtually unlmited slew rate and are better able to reproduce today’s best music and film.
3. Thermaltrak output devices: Unlike traditional designs where external diodes attached to the heat sink track the amplifiers operating conditions to adjust bias, Thermaltrak devices have the diodes in the same package as the transistors so bias is optimized in real-time.
4. Dual DC servos per channel to control DC offset.
5. Dual toroidal transformers with independent secondary windings. Electrically, each amplifier channel has its own transformer.
All the amplifiers in the 4000 series are rated at 200 Watts RMS from 20 Hz to 20 kHz with no more that 0.03% THD at 8 ohms with all channels driven and 300 Watts RMS at 4 ohms under the same conditions.
Signal-to-noise ratio is typically 126 dB referenced to full output so each amplifier in the series is capable of playing back the full dynamic range available on today’s lossless recordings.
All ATI amplifiers are available in standard (17”) and rack-mount (19”) chassis with domestic (117V) of Export (220 to 240V) chassis and are covered by ATI’s 7-year transferrable warranty.