The bandwidth of a 192kHz/24 bit system is 96kHz, and the bandwidth of SACD is 100 kHz. This matches well with the bandwidth of the GamuT D200, which is -3dB at 96kHz using the direct output and -6dB gain, which is the normal use. The bandwidth is reduced to about 75kHz in other cases like using the normal output or maximum gain. More importantly, the distortion at 1W at 100kHz is about 0.2%, a remarkably low level at these high frequencies. The protection circuitry will cut in at approximately 200W at 25kHz and 14W at 100kHz. We have set this cut point to protect tweeters against burnout in case of an unstable preamplifier or mixing console. The ear will not note these ultrasonic faults. So far, this has been very effective; music signals are passed through, and faults or inappropriate test signals will trigger the cut-off. Please note that the main advantage of 96kHz or 100kHz bandwidth is not the signals above 20 kHz as such, they are tiny and we cannot hear them anymore anyway. The advantage is avoiding time smearing of signals below 20 kHz caused by the steep brickwall filters needed in the CD format. This we can hear clearly when listening to a CD compared to live music. It may be that the fast rise-time of tones above 20 kHz also helps in localizing sources. Research to determine this is going on in Denmark at the moment. However, only special measuring microphones go flat above 40kHz. The SACD system does give out a high level of ultrasonic noise. The first SONY SACD player therefore has selectable filters at 50kHz and 75kHz, with a 5th order slope. Using the 50kHz filter the ultrasonic noise is -60dB down. Without these filters the noise is about -40dB down at 100 kHz. This is 0.02W ref 200W. The SACD standard demands the total energy to be -20dB ref maximum level. This is 2W in the case of a 200W power amplifier. We have tested our GamuT D200 at 100kHz and 2W for hours without any problems. The THD distortion is about 0.2%, and at lower power levels like 0.02W, the distortion disappears below the noise-floor of the amplifier. So we expect no problems with music from the SACD and GamuT D200. Some amplifier might have problems, as they use slow bipolar transistors in the output stage. Our SINGLE MOSFET is superior technology, which can work at much higher frequencies.