Millennium Edition

remake of a famous amplifier Design by T. Giesberts In early 1984, Elektor magazine beat the com- petition hands-down by publishing the design of a then-revolutionary MOS- FET amplifier. Even now, this amplifier enjoys an enthusiastic following. In response to many requests, we have brought the design up to date and given some attention to improved reliability and operating safety. The output power is 90 watts into 8 ohms or 135 watts into 4 ohms, which should leave little to be desired for most users. 36 Elektor Electronics 4/2001 Measured results (power supply as shown in Figure 3; quiescent current 200 mA) – input sensitivity: 1 Vrms – input impedance: 45 kΩ – sine-wave power (0.1 % THD): 90 W/8 Ω, 137 W/4 Ω – power bandwidth (80 W/8 Ω): 1.5 Hz – 300 kHz – slew rate: 60 V/µs (rise time = 1µs) – signal/noise ratio: 104 dB (A–weighted) (with respect to 1 W/8 Ω) 96 dB (BW = 22 kHz, linear)

AUDIO Crescendo Millennium Edition remake of a famous amplifier Design by T. Giesberts In early 1984, Elektor magazine beat the com- petition hands-down by publishing the design of a then-revolutionary MOS- FET amplifier. Even now, this amplifier enjoys an enthusiastic following. In response to many requests, we have brought the design up to date and given some attention to improved reliability and operating safety. The output power is 90 watts into 8 ohms or 135 watts into 4 ohms, which should leave little to be desired for most users. 36 Elektor Electronics 4/2001 AUDIO Measured results (power supply as shown in Figure 3; quiescent current 200 mA) – input sensitivity: 1 Vrms – input impedance: 45 kΩ – sine-wave power (0.1 % THD): 90 W/8 Ω, 137 W/4 Ω – power bandwidth (80 W/8 Ω): 1.5 Hz – 300 kHz – slew rate: 60 V/µs (rise time = 1µs) – signal/noise ratio: 104 dB (A–weighted) (with respect to 1 W/8 Ω) 96 dB (BW = 22 kHz, linear) – harmonic distortion at 8 Ω: at 4 Ω: (bandwidth 80 kHz): at 1 kHz: 0.002 % (1 W) 0.0026 % (1 W) 0.0017 (40 W) 0.004 % (80 W) at 20 kHz: 0.028 % (40 W) 0.04 % (80 W) – intermodulation distortion: 0.0017 % (1 W) 0.003 % (1 W) (50 Hz : 7 kHz = 4 : 1) 0.004 %…